CA2131652C - Sulfur-containing powder-metallurgy tool steel article - Google Patents
Sulfur-containing powder-metallurgy tool steel article Download PDFInfo
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- CA2131652C CA2131652C CA002131652A CA2131652A CA2131652C CA 2131652 C CA2131652 C CA 2131652C CA 002131652 A CA002131652 A CA 002131652A CA 2131652 A CA2131652 A CA 2131652A CA 2131652 C CA2131652 C CA 2131652C
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- sulfur
- tool steel
- nitrogen
- prealloyed particles
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- 229910052717 sulfur Inorganic materials 0.000 title claims abstract description 63
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 239000011593 sulfur Substances 0.000 title claims abstract description 60
- 229910001315 Tool steel Inorganic materials 0.000 title claims abstract description 44
- 238000004663 powder metallurgy Methods 0.000 title claims abstract description 29
- 239000002245 particle Substances 0.000 claims abstract description 20
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 14
- 239000000956 alloy Substances 0.000 claims abstract description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 37
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 18
- 238000004519 manufacturing process Methods 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 11
- 229910052750 molybdenum Inorganic materials 0.000 claims description 11
- 239000011733 molybdenum Substances 0.000 claims description 11
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 11
- 229910052721 tungsten Inorganic materials 0.000 claims description 11
- 239000010937 tungsten Substances 0.000 claims description 11
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 10
- 229910052804 chromium Inorganic materials 0.000 claims description 10
- 239000011651 chromium Substances 0.000 claims description 10
- 229910052720 vanadium Inorganic materials 0.000 claims description 10
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 229910052710 silicon Inorganic materials 0.000 claims description 9
- 239000010703 silicon Substances 0.000 claims description 9
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 239000011574 phosphorus Substances 0.000 claims description 6
- 239000010941 cobalt Substances 0.000 claims description 5
- 229910017052 cobalt Inorganic materials 0.000 claims description 5
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 4
- 238000009689 gas atomisation Methods 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 description 57
- 239000010959 steel Substances 0.000 description 57
- 150000004763 sulfides Chemical class 0.000 description 21
- 229960005419 nitrogen Drugs 0.000 description 12
- 239000000203 mixture Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 230000002411 adverse Effects 0.000 description 6
- 238000009826 distribution Methods 0.000 description 4
- 150000001247 metal acetylides Chemical class 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 229910000822 Cold-work tool steel Inorganic materials 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 238000007596 consolidation process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910019582 Cr V Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001513 hot isostatic pressing Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- VCTOKJRTAUILIH-UHFFFAOYSA-N manganese(2+);sulfide Chemical class [S-2].[Mn+2] VCTOKJRTAUILIH-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000012926 reference standard material Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
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- A63B21/00—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices
- A63B21/00178—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices for active exercising, the apparatus being also usable for passive exercising
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- A63B21/40—Interfaces with the user related to strength training; Details thereof
- A63B21/4041—Interfaces with the user related to strength training; Details thereof characterised by the movements of the interface
- A63B21/4047—Pivoting movement
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- A63B22/00—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements
- A63B22/0002—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements involving an exercising of arms
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- A63B22/00—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements
- A63B22/20—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements using rollers, wheels, castors or the like, e.g. gliding means, to be moved over the floor or other surface, e.g. guide tracks, during exercising
- A63B22/201—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements using rollers, wheels, castors or the like, e.g. gliding means, to be moved over the floor or other surface, e.g. guide tracks, during exercising for moving a support element in reciprocating translation, i.e. for sliding back and forth on a guide track
- A63B22/203—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements using rollers, wheels, castors or the like, e.g. gliding means, to be moved over the floor or other surface, e.g. guide tracks, during exercising for moving a support element in reciprocating translation, i.e. for sliding back and forth on a guide track in a horizontal plane
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- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B23/00—Exercising apparatus specially adapted for particular parts of the body
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
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- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B22/00—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements
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- A63B22/201—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements using rollers, wheels, castors or the like, e.g. gliding means, to be moved over the floor or other surface, e.g. guide tracks, during exercising for moving a support element in reciprocating translation, i.e. for sliding back and forth on a guide track
- A63B2022/206—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements using rollers, wheels, castors or the like, e.g. gliding means, to be moved over the floor or other surface, e.g. guide tracks, during exercising for moving a support element in reciprocating translation, i.e. for sliding back and forth on a guide track on a curved path
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- A63B71/00—Games or sports accessories not covered in groups A63B1/00 - A63B69/00
- A63B71/02—Games or sports accessories not covered in groups A63B1/00 - A63B69/00 for large-room or outdoor sporting games
- A63B71/023—Supports, e.g. poles
- A63B2071/025—Supports, e.g. poles on rollers or wheels
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- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B21/00—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices
- A63B21/005—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices using electromagnetic or electric force-resisters
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- A63B22/00—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements
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- A63B22/0023—Exercising apparatus specially adapted for conditioning the cardio-vascular system, for training agility or co-ordination of movements with an adjustable movement path of the support elements the inclination of the main axis of the movement path being adjustable, e.g. the inclination of an endless band
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- A—HUMAN NECESSITIES
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- A63B23/00—Exercising apparatus specially adapted for particular parts of the body
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- B22F2201/00—Treatment under specific atmosphere
- B22F2201/02—Nitrogen
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
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Abstract
A powder-metallurgy produced tool steel article of a hot worked, fully dense, consolidated mass of prealloyed particles of a tool steel alloy having a sulfur content within the range of 0.10 to 0.30 weight percent and a maximum sulfide size below about 15 microns.
Description
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a tool steel article made of a hot worked powder metallurgy tool steel having higher than conventional sulfur content and a method for producing the same.
Description of the Prior Art Tool steels are used conventionally in the manufacture of tooling articles employed in both cutting and noncutting tooling applications. This includes the manufacture of broaches and hobs, as well as of rolls, punches and mold components. In these tooling applications, it is necessary that the tool steel have sufficient strength, toughness, and wear resistance to withstand the service conditions encountered in these typical applications. In addition, they must have adequate machinability and grindability to facilitate production of the desired tooling components.
It is known that the presence of sulfur in tool steels improves their machinability and grindability by forming sulfides that act as a lubricant between the cutting tools used to form the tool component and the chips removed from the steel during this operation. The sulfides also promote chip breaking during the cutting operation incident to tool manufacture to thereby further facilitate this operation.
The use of sulfur in amounts over about 0.10% is known to reduce the hot workability of conventional ingot-cast tool steels and adversely affect their mechanical properties, 21316 S~
particularly their toughness. In conventional high sulfur containing tool steels, the sulfides are typically larger and elongated in the direction of hot working. Likewise, with conventional wrought tool steels, the primary carbides in the steel are strung out during hot working to form carbide stringers in the direction or working. The carbide stringers in these steels adversely affect mechanical properties, and their negative effects are so pronounced that they generally overshadow any adverse effects of the sulfides in this regard.
On the other hand, during the manufacture of high sulfur containing tool steel articles by a powder metallurgy practice wherein prealloyed particles of the steel are consolidated to achieve a fully dense article, the carbides are relatively small and well distributed compared to those in conventional tool steels. Because of the favorable size and distribution of the carbides achieved in these tool steels, the adverse effects of the carbide stringers encountered in conventional wrought steel are avoided. The properties of the powder metallurgy produced tool steels are therefore more sensitive to changes in sulfur content and to the size and distribution of the sulfides introduced for the purpose of improving their machinability or grindability.
For this reason, sulfur in amounts greater than about 0.07%, are generally not used in powder metallurgy produced tool steels because of the adverse effects of the sulfides on their mechanical properties, for example, as indicated by a 2j3~s~z decrease in the bend fracture strength of the steel. Powder metallurgy tool steel articles with higher sulfur contents would be more widely used, if the detrimental effects of sulfur on their mechanical properties could be avoided.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to provide a tool steel article produced from a hot worked powder metallurgy produced high sulfur tool steel wherein the presence of sulfur and resulting sulfides does not significantly adversely affect the mechanical properties while providing the beneficial effect of improved machinability and grindability. ' A more specific object of the invention is to provide a tool steel article made from a hot worked high sulfur containing powder metallurgy produced tool steel wherein the presence of sulfur and resulting sulfides does not significantly degrade toughness, as exhibited by the bend fracture strength.
Broadly, in accordance with the invention, there is provided a machinable powder-metallurgy produced sulfur-containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen-gas atomized, prealloyed particles of a tool steel alloy having a sulfur content of 0.10 to 0.30 weight percent with a maximum sulfide size below about 15 microns.
The tool steel alloy of the hot worked article may have a composition of a wrought high speed tool steel or of a r r v wrought cold work tool steel to which sulfur has been intentionally added within a range of 0.10 to 0.30 weight percent. Broadly, the tool steel of the hot worked article may have in weight percent 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3.00 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, and balance iron and incidental impurities. Tungsten may be substituted for molybdenum in the stoichiometric ratio of 2:1.
The machinable powder-metallurgy produced sulfur-containing tool steel article may have a minimum transverse bend fracture strength of 500 ksi when heat treated to a hardness of 64 to 66 HItC. The article comprises a hot-worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy of, in Weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorous, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.50 to 4.50 vanadium, 4.0 to 6.5 tungsten, up to 0.025 oxygen, up to 0.10 nitrogen and balance iron and incidental impurities.
The article has a maximum sulfide size below about 15 microns.
Preferably, the sulfur content of the articles in accordance with the invention may be within the range of 0.14 to 0.26%.
The invention includes a method for manufacturing a powder-metallurgy sulfur-containing tool steel article of a hot worked, fully dense, consolidated mass of nitrogen atomized, prealloyed particles of a tool steel alloy having a sulfur content of 0.10 to 0.30 weight percent with a maximum sulfide size of about 15 microns. In accordance With the method, prealloyed particles are produced by nitrogen gas atomization and are hot isostatically compacted to full density at a temperature of 2165°F and a pressure of 15 ksi.
The resulting compact is hot worked to a desired article shape at a temperature of 2050°F and the article is then annealed.
The method in the invention may also be applied to prealloyed particles of a tool steel alloy of the composition, in weight percent, 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.14 to 0.30 sulfur, up to 0.04 phosphorous, 0.20 to 1.50 silicon, 3.0 to 12.0 chromium, 0.25 to 10.0 vanadium, up to 11.0 molybdenum, up to 18.0 tungsten, up to 10.0 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities.
The method of the invention may likewise be used with prealloyed particles of a tool steel alloy of the composition, in weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorous, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.50 to 4.50 vanadium, 4.0 to 6.5 tungsten, up t 0.025 oxygen, up to 0.10 nitrogen, balance iron and incidental impurities.
Preferably, the sulfur content may be within the range of 0.14 to 0.26 weight percent.
In accordance with the invention, the carbon present in the alloy combines with chromium, vanadium, molybdenum and tungsten to form the desired dispersion of wear resistant carbides and to promote secondary hardening. Sufficient carbon is also present to provide for strengthening of the matrix of the steel. The sulfur present in the steel combines primarily with the manganese to produce manganese sulfides or manganese-rich sulfides which facilitate the machinability and grindability of the steel.
To achieve the properties needed in the powder metallurgy produced tool steel articles of this invention, it is essential that the high sulfur powder metallurgy produced tool steels used in their construction be hot worked after consolidation to achieve the high mechanical strength needed for tooling components. It is also essential that the production and processing conditions for the powder metallurgy produced tool steels used in the articles of this invention be controlled so that the sizes and distribution of the sulfides introduced by the sulfur additions do not significantly degrade mechanical properties. In the powder metallurgy produced tool steel used in the tool steel articles of this invention, this is achieved by maintaining the maximum size of the sulfides below about 15 um in their longest dimension.
In another aspect, the present invention resides in a machinable powder metallurgy produced sulfur containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy comprising in weight percent 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3.0 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities, with a maximum sulfide size below about 15 Vim.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
By way of demonstration of the invention, a series of experimental tool steels were made with varying sulfur contents and subjected to various mechanical property and machinability tests. Samples of several commercial powder metallurgy produced high speed tool steels were also subjected to the same tests for comparison. Except for sulfur, the commercial powder metallurgy tool steels generally have the same nominal composition as the experimental tool steels. The actual chemical compositions of the experimental tool steels and of the commercially produced tool steels are given in Tables I and II.
TAME I
CNEIIICAL CO~POSITI011 Of EIO~fItIlEifTAI IOIAQ lETKlURIV TOOI STEELf BarNeat MwiDarNwDerC !~ P S S1 Cr V w tb 11 0 Nt A1 92-17518-66t1.4t0.300.0010.0040.51 3.894.045.665.28 0.0340.008 - O.Ot 9t-I8518-6511.450.340.0060.050.54 5.003.775.144.90 0.0350.005 - -92-19511-6591.4t0.16- 0.140.54 3.863.805.414.90 0.0210.008 - -9t-20511-431.390.640.0050.260.57 3.863.915.795.05 0.0280.013 - -- 7a -~ CA 02131652 2003-11-13 Ta~l~ II
CHEMICAL COMPOSITION OF CO!lERCIAL HIGH SULFUR TOOL STEELS
Bar NmoarC M~ 1 S S1 H1 Cr V W Mo Co H 0 92-T91.410.690.02!0.2300.520.207.d83.915.115.270.370.030.013 92-dl1.t20.17O.OId0.2100.550.223. L995.27S.ld0.330.050.014 d9 92-T71.410.140.0220.2200.540.163. 4.015.415.130.340.050.014 d9 92-T81.400.6d0.0180.2400.550.11L903.905.405.130.130.060.011 92-TI1. 0.870.0160.2300.540.173.8I3.875.425.150.270.050.016 t5 92-T41.410.85O.O2Z0.2100.550.173.d93.94S.tb5.140.260.040.012 The production conditions for the experimental tool-steels were designed to minimize the size of the sulfides in the microstructure. They were produced from nitrogen gas atomized prealloyed powders produced from 300-pound induction melted heats. About 200 pounds of powder from each heat Were screened to -16 mesh (U. S. Standard) and loaded into 8-inch diameter, low carbon steel containers which were hot outgassed at 400°F and then sealed by welding. The containers were then heated to 2165°F and isostatically compacted at this temperature for four hours at a pressure of 15 ksi and then slowly cooled to ambient temperature. The resulting compacts were then heated to a temperature of 2050°F, hot worked to 3-inch diameter bars, and finally ~I 3i ~5z annealed using a conventional high speed tool steel annealing cycle.
The commercial powder metallurgy tool steels were produced from -16 mesh nitrogen atomized powders and are representative of materials receiving different amounts of hot reduction after consolidation by hot isostatic pressing.
No special measures were used in production of these steels to control sulfide size.
Several tests were conducted to compare the properties of the tool steel articles of the invention to those of articles made from high sulfur containing powder metallurgy tool steels of different manufacture. Tests were made to demonstrate the effects of composition and the methods of manufacture on sulfide size, bend fracture strength, impact strength, and machinability. The machinability tests were conducted on specimens in the fully annealed condition, whereas the bend fracture and impact tests were conducted on specimens in the hardened and tempered condition. The heat treatment for the latter specimens involved austenitizing for four minutes in molten salt at 2200°F, oil quenching to room temperature, and triple tempering in molten salt for 2 hours plus 2 hours plus 2 hours at 1025°F. After this heat treatment, the hardness of the specimens ranged between 64 and 66 Rockwell C.
The sizes and distribution of the sulfides in the experimental and commercial tool steels are shown in Figures 1 and 2, respectively. As expected, the number of sulfides _ g _ in experimental tool steels increase with sulfur content, as can be seen by comparing the microstructures for steels 92-17, 92-18, 92-19 and 92-20 in Figure 1. It is also clear that in accord with this invention all the sulfides in the experimental tool steels, regardless of sulfur content, are less than about 15 ~m in their longest dimension. Further, it is clear that the size of the sulfides in the experimental tool steels are considerably smaller in their largest dimensions than the sulfides in the commercial tool steels of similar composition. As shown in Figure 2, the size of the sulfides in these latter steels range from about 20 to 30 ~m in length, depending on the amount of hot reduction received in production.
The Charpy C-notch impact properties and bead fracture strengths of the experimental and commercial tool steels are given in Tables III and Iv, respectively. Comparison of the results for the experimental tool steels shows that by keeping the maximum sulfide size below 15 gym, it is possible to increase sulfur content for the purpose of improving machinability without sacrificing toughness. This is indicated by the fact that the impact and bend fracture strengths of the experimental steels in both the longitudinal and transverse directions are essentially equivalent for sulfur contents ranging between 0.005 and 0.26%, y, TaDie III
CNotcA StnnqtABend StrengtANaxfaw Iepact Fracture BerSulfurslot (ft-1b ) (ksf ) Sulfide CodeContentReductionHardnessLoneltudlnaltransverseLon9ltudinelTransverseSlze Alcrons 92-170.00485 68.5 24.0 9 757 517 d 92-180.0585 66.0 25.5 11.5 753 507 8 92-190.1485 66.0 T3.0 11 739 547 12 92-200.2685 65.0 24.0 11 711 561 15 Table IY
tHPACT ANO BEND FRACTURE STREN6Til5 OF CCI~ERCIAL TOOL STEELS1 C-NotchIapact Bend StrenqtAMexls~ur , StrenptA Fracture BarHot Hardness (ft-1D) (ks1) Sulfide CodeReductionNRC Lonvitudinel LonottudfnelTransverseSize nicrons ~ Transverse 92-T460.5 65.0 9.0 4.5 411 369 28 92-8160.5 64.5 10.0 6.0 559 389 20 92-T785.0 65.0 l8.5 5.5 672 421 T4 92-1885.0 65.0 19.0 5.3 651 383 32 927!94.0 66.0 7.0 655 397 30 92-7t99 66 lf.s 8.0 695 4x7 30 . .
O o 1 Austenlttzed at 2200'F for 4 ntnutas, 011 QuencMd, and trlpie teepend et lOZS'F for 2 plus 2 plus 2 Aoors.
Comparison of the mechanical properties for the commercial tool steels given in Table IV shows that their impact and bend fracture strengths are generally improved by increasing the amounts of hot reduction, even though it results in some elongation of the sulfides. However, because of the larger size of the sulfides in these steels, their mechanical properties are significantly lower than those of the experimental tool steels having essentially the same composition and amount of hot reduction. Compare, for example, the mechanical properties of Steel 92-20 (0.26% S) which has a maximum sulfide size of about 15 ~m and longitudinal and transverse bend fracture strengths of 771 and 561 ksi, respectively, with those of Steel 92-78 (0.24% S) with a maximum sulfide size of about 30 pm and longitudinal and transverse bend fracture strengths of 651 and 383 ksi, respectively.
The results of the drill machinability tests conducted on the experimental tool steels in the annealed condition are given in Table V. The drill machinability indexes in this table were obtained by comparing the times required to drill holes of the same size and depth in these steels and by multiplying the ratios of the times for each steel to that for the experimental steel with 0.005% sulfur by 100.
Indexes greater than 100 indicate that the drill machinability of the steel being tested is greater than that of the experimental tool steel article containing 0.005%
sulfur (Steel 91-60). The results show that increasing sulfur from 0.005 to 0-~6% improves machinability of the experimental tool steels and that the greater improvement is achieved at sulfur contents at or above about 0.14%.
Table V
EFFECT OF SULFUR CONTENT ON THE DRILL
MACHINAHILITY OF EXPERIMENTAL TOOL STEELS
Har Hardness Drill Machinabilitv Index-MI1 dumber % S HRC Test Values' Avct.
91-17 0.005 21 100, 100, I00 100 91-18 0.05 21 104, 104, 109 106 91-19 0.14 22 117, 116, 127 120 91-20 0.26 21 140, 134, 150 141 Drill Time to Drill Test Material Machinability - x 100 Index Time to Drill Reference Standard Material It may be seen from the above that by reducing the size of the sulfides in articles made from hot worked powder metallurgy tool steels, it is possible to substantially negate the negative effects of high sulfur contents on their properties. Hence, with the invention it is possible to produce powder metallurgy tool steel articles with sulfur contents higher than conventionally permitted to achieve improved machinability without significant degradation of the mechanical properties, particularly as exhibited by the bend fracture strength of the steel.
The term "sulfur containing tool steel article" is restricted to cold work tool steels and high speed tool steels.
Field of the Invention This invention relates to a tool steel article made of a hot worked powder metallurgy tool steel having higher than conventional sulfur content and a method for producing the same.
Description of the Prior Art Tool steels are used conventionally in the manufacture of tooling articles employed in both cutting and noncutting tooling applications. This includes the manufacture of broaches and hobs, as well as of rolls, punches and mold components. In these tooling applications, it is necessary that the tool steel have sufficient strength, toughness, and wear resistance to withstand the service conditions encountered in these typical applications. In addition, they must have adequate machinability and grindability to facilitate production of the desired tooling components.
It is known that the presence of sulfur in tool steels improves their machinability and grindability by forming sulfides that act as a lubricant between the cutting tools used to form the tool component and the chips removed from the steel during this operation. The sulfides also promote chip breaking during the cutting operation incident to tool manufacture to thereby further facilitate this operation.
The use of sulfur in amounts over about 0.10% is known to reduce the hot workability of conventional ingot-cast tool steels and adversely affect their mechanical properties, 21316 S~
particularly their toughness. In conventional high sulfur containing tool steels, the sulfides are typically larger and elongated in the direction of hot working. Likewise, with conventional wrought tool steels, the primary carbides in the steel are strung out during hot working to form carbide stringers in the direction or working. The carbide stringers in these steels adversely affect mechanical properties, and their negative effects are so pronounced that they generally overshadow any adverse effects of the sulfides in this regard.
On the other hand, during the manufacture of high sulfur containing tool steel articles by a powder metallurgy practice wherein prealloyed particles of the steel are consolidated to achieve a fully dense article, the carbides are relatively small and well distributed compared to those in conventional tool steels. Because of the favorable size and distribution of the carbides achieved in these tool steels, the adverse effects of the carbide stringers encountered in conventional wrought steel are avoided. The properties of the powder metallurgy produced tool steels are therefore more sensitive to changes in sulfur content and to the size and distribution of the sulfides introduced for the purpose of improving their machinability or grindability.
For this reason, sulfur in amounts greater than about 0.07%, are generally not used in powder metallurgy produced tool steels because of the adverse effects of the sulfides on their mechanical properties, for example, as indicated by a 2j3~s~z decrease in the bend fracture strength of the steel. Powder metallurgy tool steel articles with higher sulfur contents would be more widely used, if the detrimental effects of sulfur on their mechanical properties could be avoided.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to provide a tool steel article produced from a hot worked powder metallurgy produced high sulfur tool steel wherein the presence of sulfur and resulting sulfides does not significantly adversely affect the mechanical properties while providing the beneficial effect of improved machinability and grindability. ' A more specific object of the invention is to provide a tool steel article made from a hot worked high sulfur containing powder metallurgy produced tool steel wherein the presence of sulfur and resulting sulfides does not significantly degrade toughness, as exhibited by the bend fracture strength.
Broadly, in accordance with the invention, there is provided a machinable powder-metallurgy produced sulfur-containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen-gas atomized, prealloyed particles of a tool steel alloy having a sulfur content of 0.10 to 0.30 weight percent with a maximum sulfide size below about 15 microns.
The tool steel alloy of the hot worked article may have a composition of a wrought high speed tool steel or of a r r v wrought cold work tool steel to which sulfur has been intentionally added within a range of 0.10 to 0.30 weight percent. Broadly, the tool steel of the hot worked article may have in weight percent 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3.00 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, and balance iron and incidental impurities. Tungsten may be substituted for molybdenum in the stoichiometric ratio of 2:1.
The machinable powder-metallurgy produced sulfur-containing tool steel article may have a minimum transverse bend fracture strength of 500 ksi when heat treated to a hardness of 64 to 66 HItC. The article comprises a hot-worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy of, in Weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorous, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.50 to 4.50 vanadium, 4.0 to 6.5 tungsten, up to 0.025 oxygen, up to 0.10 nitrogen and balance iron and incidental impurities.
The article has a maximum sulfide size below about 15 microns.
Preferably, the sulfur content of the articles in accordance with the invention may be within the range of 0.14 to 0.26%.
The invention includes a method for manufacturing a powder-metallurgy sulfur-containing tool steel article of a hot worked, fully dense, consolidated mass of nitrogen atomized, prealloyed particles of a tool steel alloy having a sulfur content of 0.10 to 0.30 weight percent with a maximum sulfide size of about 15 microns. In accordance With the method, prealloyed particles are produced by nitrogen gas atomization and are hot isostatically compacted to full density at a temperature of 2165°F and a pressure of 15 ksi.
The resulting compact is hot worked to a desired article shape at a temperature of 2050°F and the article is then annealed.
The method in the invention may also be applied to prealloyed particles of a tool steel alloy of the composition, in weight percent, 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.14 to 0.30 sulfur, up to 0.04 phosphorous, 0.20 to 1.50 silicon, 3.0 to 12.0 chromium, 0.25 to 10.0 vanadium, up to 11.0 molybdenum, up to 18.0 tungsten, up to 10.0 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities.
The method of the invention may likewise be used with prealloyed particles of a tool steel alloy of the composition, in weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorous, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.50 to 4.50 vanadium, 4.0 to 6.5 tungsten, up t 0.025 oxygen, up to 0.10 nitrogen, balance iron and incidental impurities.
Preferably, the sulfur content may be within the range of 0.14 to 0.26 weight percent.
In accordance with the invention, the carbon present in the alloy combines with chromium, vanadium, molybdenum and tungsten to form the desired dispersion of wear resistant carbides and to promote secondary hardening. Sufficient carbon is also present to provide for strengthening of the matrix of the steel. The sulfur present in the steel combines primarily with the manganese to produce manganese sulfides or manganese-rich sulfides which facilitate the machinability and grindability of the steel.
To achieve the properties needed in the powder metallurgy produced tool steel articles of this invention, it is essential that the high sulfur powder metallurgy produced tool steels used in their construction be hot worked after consolidation to achieve the high mechanical strength needed for tooling components. It is also essential that the production and processing conditions for the powder metallurgy produced tool steels used in the articles of this invention be controlled so that the sizes and distribution of the sulfides introduced by the sulfur additions do not significantly degrade mechanical properties. In the powder metallurgy produced tool steel used in the tool steel articles of this invention, this is achieved by maintaining the maximum size of the sulfides below about 15 um in their longest dimension.
In another aspect, the present invention resides in a machinable powder metallurgy produced sulfur containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy comprising in weight percent 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3.0 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities, with a maximum sulfide size below about 15 Vim.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
By way of demonstration of the invention, a series of experimental tool steels were made with varying sulfur contents and subjected to various mechanical property and machinability tests. Samples of several commercial powder metallurgy produced high speed tool steels were also subjected to the same tests for comparison. Except for sulfur, the commercial powder metallurgy tool steels generally have the same nominal composition as the experimental tool steels. The actual chemical compositions of the experimental tool steels and of the commercially produced tool steels are given in Tables I and II.
TAME I
CNEIIICAL CO~POSITI011 Of EIO~fItIlEifTAI IOIAQ lETKlURIV TOOI STEELf BarNeat MwiDarNwDerC !~ P S S1 Cr V w tb 11 0 Nt A1 92-17518-66t1.4t0.300.0010.0040.51 3.894.045.665.28 0.0340.008 - O.Ot 9t-I8518-6511.450.340.0060.050.54 5.003.775.144.90 0.0350.005 - -92-19511-6591.4t0.16- 0.140.54 3.863.805.414.90 0.0210.008 - -9t-20511-431.390.640.0050.260.57 3.863.915.795.05 0.0280.013 - -- 7a -~ CA 02131652 2003-11-13 Ta~l~ II
CHEMICAL COMPOSITION OF CO!lERCIAL HIGH SULFUR TOOL STEELS
Bar NmoarC M~ 1 S S1 H1 Cr V W Mo Co H 0 92-T91.410.690.02!0.2300.520.207.d83.915.115.270.370.030.013 92-dl1.t20.17O.OId0.2100.550.223. L995.27S.ld0.330.050.014 d9 92-T71.410.140.0220.2200.540.163. 4.015.415.130.340.050.014 d9 92-T81.400.6d0.0180.2400.550.11L903.905.405.130.130.060.011 92-TI1. 0.870.0160.2300.540.173.8I3.875.425.150.270.050.016 t5 92-T41.410.85O.O2Z0.2100.550.173.d93.94S.tb5.140.260.040.012 The production conditions for the experimental tool-steels were designed to minimize the size of the sulfides in the microstructure. They were produced from nitrogen gas atomized prealloyed powders produced from 300-pound induction melted heats. About 200 pounds of powder from each heat Were screened to -16 mesh (U. S. Standard) and loaded into 8-inch diameter, low carbon steel containers which were hot outgassed at 400°F and then sealed by welding. The containers were then heated to 2165°F and isostatically compacted at this temperature for four hours at a pressure of 15 ksi and then slowly cooled to ambient temperature. The resulting compacts were then heated to a temperature of 2050°F, hot worked to 3-inch diameter bars, and finally ~I 3i ~5z annealed using a conventional high speed tool steel annealing cycle.
The commercial powder metallurgy tool steels were produced from -16 mesh nitrogen atomized powders and are representative of materials receiving different amounts of hot reduction after consolidation by hot isostatic pressing.
No special measures were used in production of these steels to control sulfide size.
Several tests were conducted to compare the properties of the tool steel articles of the invention to those of articles made from high sulfur containing powder metallurgy tool steels of different manufacture. Tests were made to demonstrate the effects of composition and the methods of manufacture on sulfide size, bend fracture strength, impact strength, and machinability. The machinability tests were conducted on specimens in the fully annealed condition, whereas the bend fracture and impact tests were conducted on specimens in the hardened and tempered condition. The heat treatment for the latter specimens involved austenitizing for four minutes in molten salt at 2200°F, oil quenching to room temperature, and triple tempering in molten salt for 2 hours plus 2 hours plus 2 hours at 1025°F. After this heat treatment, the hardness of the specimens ranged between 64 and 66 Rockwell C.
The sizes and distribution of the sulfides in the experimental and commercial tool steels are shown in Figures 1 and 2, respectively. As expected, the number of sulfides _ g _ in experimental tool steels increase with sulfur content, as can be seen by comparing the microstructures for steels 92-17, 92-18, 92-19 and 92-20 in Figure 1. It is also clear that in accord with this invention all the sulfides in the experimental tool steels, regardless of sulfur content, are less than about 15 ~m in their longest dimension. Further, it is clear that the size of the sulfides in the experimental tool steels are considerably smaller in their largest dimensions than the sulfides in the commercial tool steels of similar composition. As shown in Figure 2, the size of the sulfides in these latter steels range from about 20 to 30 ~m in length, depending on the amount of hot reduction received in production.
The Charpy C-notch impact properties and bead fracture strengths of the experimental and commercial tool steels are given in Tables III and Iv, respectively. Comparison of the results for the experimental tool steels shows that by keeping the maximum sulfide size below 15 gym, it is possible to increase sulfur content for the purpose of improving machinability without sacrificing toughness. This is indicated by the fact that the impact and bend fracture strengths of the experimental steels in both the longitudinal and transverse directions are essentially equivalent for sulfur contents ranging between 0.005 and 0.26%, y, TaDie III
CNotcA StnnqtABend StrengtANaxfaw Iepact Fracture BerSulfurslot (ft-1b ) (ksf ) Sulfide CodeContentReductionHardnessLoneltudlnaltransverseLon9ltudinelTransverseSlze Alcrons 92-170.00485 68.5 24.0 9 757 517 d 92-180.0585 66.0 25.5 11.5 753 507 8 92-190.1485 66.0 T3.0 11 739 547 12 92-200.2685 65.0 24.0 11 711 561 15 Table IY
tHPACT ANO BEND FRACTURE STREN6Til5 OF CCI~ERCIAL TOOL STEELS1 C-NotchIapact Bend StrenqtAMexls~ur , StrenptA Fracture BarHot Hardness (ft-1D) (ks1) Sulfide CodeReductionNRC Lonvitudinel LonottudfnelTransverseSize nicrons ~ Transverse 92-T460.5 65.0 9.0 4.5 411 369 28 92-8160.5 64.5 10.0 6.0 559 389 20 92-T785.0 65.0 l8.5 5.5 672 421 T4 92-1885.0 65.0 19.0 5.3 651 383 32 927!94.0 66.0 7.0 655 397 30 92-7t99 66 lf.s 8.0 695 4x7 30 . .
O o 1 Austenlttzed at 2200'F for 4 ntnutas, 011 QuencMd, and trlpie teepend et lOZS'F for 2 plus 2 plus 2 Aoors.
Comparison of the mechanical properties for the commercial tool steels given in Table IV shows that their impact and bend fracture strengths are generally improved by increasing the amounts of hot reduction, even though it results in some elongation of the sulfides. However, because of the larger size of the sulfides in these steels, their mechanical properties are significantly lower than those of the experimental tool steels having essentially the same composition and amount of hot reduction. Compare, for example, the mechanical properties of Steel 92-20 (0.26% S) which has a maximum sulfide size of about 15 ~m and longitudinal and transverse bend fracture strengths of 771 and 561 ksi, respectively, with those of Steel 92-78 (0.24% S) with a maximum sulfide size of about 30 pm and longitudinal and transverse bend fracture strengths of 651 and 383 ksi, respectively.
The results of the drill machinability tests conducted on the experimental tool steels in the annealed condition are given in Table V. The drill machinability indexes in this table were obtained by comparing the times required to drill holes of the same size and depth in these steels and by multiplying the ratios of the times for each steel to that for the experimental steel with 0.005% sulfur by 100.
Indexes greater than 100 indicate that the drill machinability of the steel being tested is greater than that of the experimental tool steel article containing 0.005%
sulfur (Steel 91-60). The results show that increasing sulfur from 0.005 to 0-~6% improves machinability of the experimental tool steels and that the greater improvement is achieved at sulfur contents at or above about 0.14%.
Table V
EFFECT OF SULFUR CONTENT ON THE DRILL
MACHINAHILITY OF EXPERIMENTAL TOOL STEELS
Har Hardness Drill Machinabilitv Index-MI1 dumber % S HRC Test Values' Avct.
91-17 0.005 21 100, 100, I00 100 91-18 0.05 21 104, 104, 109 106 91-19 0.14 22 117, 116, 127 120 91-20 0.26 21 140, 134, 150 141 Drill Time to Drill Test Material Machinability - x 100 Index Time to Drill Reference Standard Material It may be seen from the above that by reducing the size of the sulfides in articles made from hot worked powder metallurgy tool steels, it is possible to substantially negate the negative effects of high sulfur contents on their properties. Hence, with the invention it is possible to produce powder metallurgy tool steel articles with sulfur contents higher than conventionally permitted to achieve improved machinability without significant degradation of the mechanical properties, particularly as exhibited by the bend fracture strength of the steel.
The term "sulfur containing tool steel article" is restricted to cold work tool steels and high speed tool steels.
Claims (7)
1. A machinable powder metallurgy produced sulfur containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy comprising in weight percent 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3.0 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities, with a maximum sulfide size below about 15 µm.
2. A machinable powder metallurgy produced sulfur containing tool steel article having a minimum transverse bend fracture strength of 500 ksi when heat treated to a hardness of 64 to 66 HRC, said article comprising a hot worked, fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy consisting essentially of, in weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorus, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.50 to 4.50 vanadium, 4.0 to 6.5 tungsten, up to 0.025 oxygen, up to 0.10 nitrogen, balance iron and incidental impurities, and said article having a maximum sulfide size below about 15 µm.
3. A powder metallurgy produced sulfur bearing tool steel article of claims 1, or 2 in which the sulfur content is within the range of 0.14 to 0.26 percent.
4. A method for manufacturing a powder metallurgy sulfur containing tool steel article comprising a hot worked, fully dense, consolidated mass of nitrogen atomized, prealloyed particles of a tool steel alloy having a sulfur content of 0.10 to 0.30 weight percent with a maximum sulfide size of about 15 µm; said method comprising producing said prealloyed particles by nitrogen gas atomization, hot isostatically compacting the prealloyed particles to full density at a temperature of 2165°F. and at a pressure of 15 ksi, hot working the resulting compact to a desired shape of the article at a temperature of 2050°F., and annealing said article.
5. A method for manufacturing a powder metallurgy sulfur containing tool steel article, comprising a hot worked fully dense, consolidated mass of nitrogen gas atomized, prealloyed particles of a tool steel alloy comprising, in weight percent, 0.80 to 3.00 carbon, 0.20 to 2.00 manganese, 0.10 to 0.30 sulfur, up to 0.04 phosphorus, 0.20 to 1.50 silicon, 3 to 12.00 chromium, 0.25 to 10.00 vanadium, up to 11.00 molybdenum, up to 18.00 tungsten, up to 10.00 cobalt, up to 0.10 nitrogen, up to 0.025 oxygen, balance iron and incidental impurities and with a maximum sulfide size of 15 µm, said method comprising producing said prealloyed particles by nitrogen gas atomization, hot isostatically compacting the prealloyed particles to full density at a temperature of 2165°F. and a pressure of 15 ksi, hot working the resulting compact to a desired shape of the article at a temperature of 2050°F., and annealing said article.
6. A method for manufacturing a powder metallurgy sulfur containing tool steel article having a minimum transverse bend fracture strength of 500 ksi when heat treated to a hardness of 64 to 66 HRC, said article comprising a hot worked, fully dense, consolidated mass of nitrogen atomized, prealloyed particles of a tool steel alloy consisting essentially of, in weight percent, 1.25 to 1.50 carbon, 0.20 to 1.00 manganese, 0.10 to 0.26 sulfur, up to 0.04 phosphorus, up to 1.00 silicon, 3.0 to 6.0 chromium, 4.0 to 6.0 molybdenum, 3.5 to 4.50 vanadium, 4.0 to 6.5 tungsten, up to 0.025 oxygen, up to 0.10 nitrogen, balance iron and incidental impurities with a maximum sulfide size of about 15 µm, said method producing said prealloyed particles by nitrogen gas atomization, compacting the prealloyed particles to full density at 2165°F., and at a pressure of 15 ksi, hot working the compact to a desired shape of the article at 2050°F. and annealing said article.
7. The method of claims 4, 5 or 6 in which the sulfur content is within the range of 0.14 to 0.26 weight percent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12656293A | 1993-09-27 | 1993-09-27 | |
| US08/126,562 | 1993-09-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2131652A1 CA2131652A1 (en) | 1995-03-28 |
| CA2131652C true CA2131652C (en) | 2004-06-01 |
Family
ID=22425515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002131652A Expired - Fee Related CA2131652C (en) | 1993-09-27 | 1994-09-08 | Sulfur-containing powder-metallurgy tool steel article |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0648851B1 (en) |
| JP (1) | JPH07179908A (en) |
| AT (1) | ATE182183T1 (en) |
| CA (1) | CA2131652C (en) |
| DE (1) | DE69419474T2 (en) |
| DK (1) | DK0648851T3 (en) |
| ES (1) | ES2135544T3 (en) |
| GR (1) | GR3031225T3 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5679908A (en) * | 1995-11-08 | 1997-10-21 | Crucible Materials Corporation | Corrosion resistant, high vanadium, powder metallurgy tool steel articles with improved metal to metal wear resistance and a method for producing the same |
| SE508872C2 (en) * | 1997-03-11 | 1998-11-09 | Erasteel Kloster Ab | Powder metallurgically made steel for tools, tools made therefrom, process for making steel and tools and use of steel |
| AT411580B (en) * | 2001-04-11 | 2004-03-25 | Boehler Edelstahl | METHOD FOR THE POWDER METALLURGICAL PRODUCTION OF OBJECTS |
| AT412000B (en) * | 2003-04-24 | 2004-08-26 | Boehler Edelstahl Gmbh & Co Kg | Cold-worked steel with greater strength and increased ductility, used for, e.g., pressing tools and forgings, has specified composition |
| GB0912669D0 (en) * | 2009-07-21 | 2009-08-26 | Skf Publ Ab | Bearing steels |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3598567A (en) * | 1968-07-01 | 1971-08-10 | Nicholas J Grant | Stainless steel powder product |
| JPS5817802B2 (en) * | 1980-03-03 | 1983-04-09 | 株式会社神戸製鋼所 | Hot working method for powder high speed steel |
| SE445715B (en) * | 1984-11-30 | 1986-07-14 | Hoeganaes Ab | MANGANESULPHIDIC IRON POWDER MIXTURE |
| JPS63149707A (en) * | 1986-12-15 | 1988-06-22 | Fujitsu Ltd | Method for forming speed command of robot |
| JPH02232302A (en) * | 1989-03-04 | 1990-09-14 | Daido Steel Co Ltd | Manufacture of powder high alloy steel rolled material |
| CH680137A5 (en) * | 1989-12-22 | 1992-06-30 | Htm Ag | |
| JPH03247743A (en) * | 1990-02-26 | 1991-11-05 | Kawasaki Steel Corp | Sintered alloy steel excellent in corrosion resistance, machinability and mirror finishing property and its manufacture |
| JPH0480305A (en) * | 1990-07-24 | 1992-03-13 | Daido Steel Co Ltd | Manufacture of powder high speed steel product |
| US5238482A (en) * | 1991-05-22 | 1993-08-24 | Crucible Materials Corporation | Prealloyed high-vanadium, cold work tool steel particles and methods for producing the same |
-
1994
- 1994-09-08 CA CA002131652A patent/CA2131652C/en not_active Expired - Fee Related
- 1994-09-09 ES ES94306632T patent/ES2135544T3/en not_active Expired - Lifetime
- 1994-09-09 DK DK94306632T patent/DK0648851T3/en active
- 1994-09-09 EP EP94306632A patent/EP0648851B1/en not_active Revoked
- 1994-09-09 DE DE69419474T patent/DE69419474T2/en not_active Expired - Fee Related
- 1994-09-09 AT AT94306632T patent/ATE182183T1/en not_active IP Right Cessation
- 1994-09-26 JP JP6254124A patent/JPH07179908A/en active Pending
-
1999
- 1999-09-16 GR GR990402316T patent/GR3031225T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DK0648851T3 (en) | 1999-11-29 |
| ES2135544T3 (en) | 1999-11-01 |
| DE69419474T2 (en) | 2000-03-16 |
| ATE182183T1 (en) | 1999-07-15 |
| GR3031225T3 (en) | 1999-12-31 |
| DE69419474D1 (en) | 1999-08-19 |
| EP0648851B1 (en) | 1999-07-14 |
| EP0648851A1 (en) | 1995-04-19 |
| CA2131652A1 (en) | 1995-03-28 |
| JPH07179908A (en) | 1995-07-18 |
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