CN109609836B - Production method of as-cast thick large-section nodular cast iron and cast product thereof - Google Patents
Production method of as-cast thick large-section nodular cast iron and cast product thereof Download PDFInfo
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- 229910001141 Ductile iron Inorganic materials 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 238000005266 casting Methods 0.000 claims abstract description 34
- 238000000034 method Methods 0.000 claims abstract description 20
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 20
- 239000010703 silicon Substances 0.000 claims abstract description 20
- 239000002054 inoculum Substances 0.000 claims abstract description 19
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 18
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 16
- 239000011593 sulfur Substances 0.000 claims abstract description 16
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000011574 phosphorus Substances 0.000 claims abstract description 14
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 14
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 11
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 9
- 239000011572 manganese Substances 0.000 claims abstract description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 8
- OOJQNBIDYDPHHE-UHFFFAOYSA-N barium silicon Chemical compound [Si].[Ba] OOJQNBIDYDPHHE-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 239000011651 chromium Substances 0.000 claims abstract description 8
- 229910052802 copper Inorganic materials 0.000 claims abstract description 8
- 239000010949 copper Substances 0.000 claims abstract description 8
- 229910052742 iron Inorganic materials 0.000 claims abstract description 8
- 239000000126 substance Substances 0.000 claims abstract description 8
- 229910000805 Pig iron Inorganic materials 0.000 claims abstract description 7
- 239000013078 crystal Substances 0.000 claims abstract description 6
- 230000005496 eutectics Effects 0.000 claims abstract description 6
- 229910001562 pearlite Inorganic materials 0.000 claims abstract description 6
- 229910000975 Carbon steel Inorganic materials 0.000 claims abstract description 5
- 239000010962 carbon steel Substances 0.000 claims abstract description 5
- 239000004615 ingredient Substances 0.000 claims abstract description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 16
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 238000005422 blasting Methods 0.000 claims description 6
- 229910052791 calcium Inorganic materials 0.000 claims description 6
- 239000011575 calcium Substances 0.000 claims description 6
- 229910052788 barium Inorganic materials 0.000 claims description 5
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 5
- 229910000976 Electrical steel Inorganic materials 0.000 claims description 4
- 238000011081 inoculation Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 claims description 3
- 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 3
- 239000003110 molding sand Substances 0.000 claims description 3
- 238000001514 detection method Methods 0.000 description 12
- 238000012360 testing method Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229910001018 Cast iron Inorganic materials 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000005555 metalworking Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Images
Classifications
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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
- C22C33/08—Making cast-iron alloys
- C22C33/10—Making cast-iron alloys including procedures for adding magnesium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/04—Cast-iron alloys containing spheroidal graphite
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention relates to a production method of as-cast thick large-section nodular cast iron, which comprises the following steps: the ingredients comprise: benxi pig iron Q10; the carbon steel scrap is spheroidized by adopting a three-Ming-technology method at 1500 +/-20 ℃ after molten iron is prepared: adding a rare earth nodulizer, a silicon-barium inoculant and a covering agent, wherein the nodulizing time is 65-80 seconds, the nodulizing rate is more than 85 percent, and the rare earth inoculant is added, so that the prepared molded casting comprises the following chemical components: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent. The tensile strength of the invention is more than or equal to 600Mpa, the yield strength is more than or equal to 450Mpa, the elongation is more than or equal to 12 percent, the spheroidization rate is more than or equal to 85 percent, the pearlite content is 2 to 5 percent, and free carbide and phosphorus eutectic crystal are not generated.
Description
Technical Field
The invention relates to the field of casting processing, in particular to a production method of as-cast thick large-section nodular cast iron and a casting product prepared by the method.
Background
The ductile iron is a high-strength cast iron material developed in the 20 th century and the fifties, the comprehensive performance of the ductile iron is close to that of steel, and the ductile iron is successfully used for casting parts which are complex in stress and high in requirements on strength, toughness and wear resistance based on the excellent performance of the ductile iron. Nodular cast iron has rapidly evolved to a very widely used cast iron material second only to gray cast iron. The nodular cast iron is spheroidized and inoculated to obtain spheroidal graphite, so that the mechanical properties of the cast iron are effectively improved, and particularly, the plasticity and toughness are improved, so that the strength of the cast iron is higher than that of carbon steel.
The nodular cast iron with the mark QT600-10 has higher tensile strength and higher elongation. At present, the national standard does not aim at QT 600-10. At present, the requirements of thick and large section nodular cast iron QT600-10 of manufacturers in China that the tensile strength is more than or equal to 600, the yield strength is more than or equal to 370 and the elongation is more than or equal to 10 can be met by performing a heat treatment process. The heat treatment is a metal hot working process which obtains expected structure and performance by means of heating, heat preservation and cooling in a solid state, and is an indispensable step in the metal working process.
Disclosure of Invention
The invention aims to provide a production method of as-cast thick and large section nodular cast iron, in particular to a QT600-10 production method of as-cast thick and large section high-strength high-elongation nodular cast iron.
In order to achieve the purpose, the invention adopts the technical scheme that:
a production method of as-cast heavy section nodular cast iron comprises the following steps:
(1) the ingredients comprise:
pig iron: benxi pig iron Q10;
scrap steel: carbon steel scrap, wherein: less than or equal to 0.4 percent of manganese,
(2) and spheroidizing: spheroidizing by adopting a Sanming method at 1500 +/-20 ℃ after molten iron is prepared: adding 1.2-1.4% of rare earth nodulizer, 0.6-0.8% of silicon-barium inoculant and 1.0-1.2% of covering agent, wherein the nodulizing time is 65-80 seconds, the nodulizing rate is more than 85%,
(3) and casting: adopting stream inoculation of 0.2-0.4% rare earth inoculant, wherein the pouring temperature of a first box is 1390-,
(4) and the chemical component content of the formed casting is as follows: carbon: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent.
Preferably, wherein: nodulizing agent: the granularity is 5-20mm, and the silicon content is 44-46%; 0.50 to 0.60 percent of rare earth; the magnesium content is 5-7%; 0.5 to 1.5 percent of calcium; 0.70 to 0.80 percent of aluminum;
silicon-barium inoculant: the grain size of the agent is 1-3mm, the silicon content is 70-75%, and the barium content is 1-3%;
rare earth inoculant: the particle size of the stream inoculant is 0.2-0.6mm, and the silicon content is 70-75%; 2.0 to 2.5 percent of barium; calcium content is 1.50-1.60%; 1.2 to 1.6 percent of aluminum; 1.3 to 1.7 percent of rare earth;
covering agent: a silicon steel sheet;
casting molding sand: the granularity is 57-63.
Preferably, the following requirements are met by carrying out one-time chemical component detection before tapping:
carbon: 3.10 to 3.30 percent; silicon: 2.80-3.0%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent.
Further preferably, a carburant is selected to adjust the carbon content, the carburant: the low-sulfur carburant contains less than or equal to 0.05% of sulfur and less than or equal to 300ppm of N gas.
Preferably, the tail box of each ladle is poured to manufacture a rapid metallographic test block and a spectrum test block, and the detection spheroidization rate is not lower than 90%.
Preferably, the casting is offline after the casting is finished for 2 hours, the casting body is detected, and the detection requirement is as follows: the spheroidization rate is not less than 85 percent, the pearlite content is not more than 5 percent, and free carbides and phosphorus eutectic are not generated.
Preferably, the casting is off-line after being poured for 2 hours, shot blasting is carried out, and the tail box of each furnace is removed after the shot blasting is finished to detect the mechanical property and the metallographic property of the casting.
Preferably, a return material is added into the ingredients, and the ratio of the return material to the scrap steel is 6: 4.
Preferably, the method does not comprise a heat treatment process.
The invention also aims to provide a casting product prepared by the production method of the as-cast thick large-section ductile iron.
In order to achieve the purpose, the invention adopts the technical scheme that:
a casting product prepared by a production method of as-cast thick and large-section nodular cast iron comprises the following chemical components: carbon: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent; the balance being iron.
Preferably, the casting product is an engineering machinery hub casting.
The inventive principle of the present application:
spheroidization rate: ensuring that the content is more than 85 percent, and controlling the method: the low rare earth nodulizer with the granularity of 5-20mm is adopted to reduce gaps among particles, the silicon barium inoculant with the granularity of 1-3mm is used for filling, so that the filling of the whole nodulizing chamber is more compact, and then the silicon steel sheet covering agent is used for covering, so that the nodulizer is layered, detonated and nodulized during nodulizing, the nodulizing time is prolonged, and the nodulizing efficiency is improved; a funnel directional feeding mode is used, so that the spheroidization control of each package is in a stable state; three layers of fast metallographic test block, attached test block and spheroidizing reaction timer are used for closing.
Yield strength: 370 MPa.
Tensile strength: 600 Mpa; the control means is as follows: the main elements are controlled to form a metallographic matrix with ferrite as a main element, the tensile strength and the yield strength are improved by utilizing the solid solution strengthening effect of silicon, the control range is narrowed, the control on the tensile yield strength is more accurate, the error of the tensile strength is controlled to be 30Mpa, and the error of the yield strength is controlled to be 15 Mpa; the silicon content is improved, and the solid solution strengthening effect of the silicon is enhanced. In actual production, the tensile strength is 620 +/-15 MPa, and the yield strength is 500 +/-10 MPa.
Free carbide content, phosphorus eutectic crystal and elongation percentage of 10 percent are avoided; the control means is as follows: the spheroidization rate is controlled to be more than 85 percent, the silicon content is controlled to be 3.80-4.10 percent, the low alloying is adopted, 3 times of inoculation is adopted, the number of graphite cores is increased, the graphite is refined, and meanwhile, the cold iron is matched with the thick and large hot junctions to accelerate the solidification and the refinement of crystal grains, so that the generation of blocky graphite is prevented, the interior of a product is more compact, the graphite form is more complete, the spheroidization rate and the elongation rate are effectively improved, the method is used for controlling, and the actual elongation rate is controlled to be 15-20 percent.
The shrinkage porosity defect cannot be caused: the control means is as follows: low shrinkage tendency: the sequential solidification pouring process design improves the temperature difference and feeding capacity of the casting adjustment of the process, prevents shrinkage porosity and reduces the potential safety hazard of products; a high-heating heat-insulating riser is additionally adopted at a proper position, so that enough liquid shrinkage is provided for the casting, and the inside of the casting is guaranteed to be compact.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages and effects:
in the invention: the tensile strength is more than or equal to 600Mpa, the yield strength is more than or equal to 450Mpa, the elongation is more than or equal to 12 percent, the spheroidization rate is more than or equal to 85 percent, the pearlite content is 2 to 5 percent, and free carbide content and phosphorus eutectic crystal are avoided.
Drawings
FIG. 1 is a schematic diagram of the product of this example.
Detailed Description
The invention is further described below with reference to the accompanying drawings and embodiments:
processing the hub casting of the engineering machinery shown in figure 1, wherein a: 273mm, b: 95mm, c, 74mm, d: 540 mm. For c is the sample position. The method comprises the following steps:
preparing ingredients:
pig iron: benxi pig iron Q10;
scrap steel, foundry returns, scrap steel: carbon steel scrap, wherein: manganese is less than or equal to 0.4 percent, and the proportion of the returned material to the scrap steel is 6: 4;
nodulizing agent: french iron alloy ZM-N5701 nodulizer with granularity of 5-20mm and silicon content of 45%; 0.55 percent of rare earth; the magnesium content is 6 percent; 1.0 percent of calcium; 0.75 percent of aluminum;
inoculant: the spheroidizing inoculant adopts a silicon-barium inoculant with the granularity of 1-3mm, the stream-following inoculant adopts a French iron alloy 65260 stream-following inoculant with the granularity of 0.2-0.6mm and contains 72% of silicon; 2.3 percent of barium; 1.53 percent of calcium; 1.4 percent of aluminum; 1.5 percent of rare earth;
covering agent: a silicon steel sheet;
carburant: the sulfur content of the low-sulfur carburant is less than or equal to 0.05 percent, and the N gas content is less than or equal to 300 ppm;
casting molding sand: the granularity is 57-63.
The following requirements are met by carrying out one-time chemical component detection before tapping, wherein: the carbon and sulfur detection uses a German Bruk carbon and sulfur instrument, and the other components are detected by adopting a German Bruk spectrometer:
carbon: 3.10 to 3.30 percent; silicon: 2.80-3.0%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent.
Spheroidizing by adopting a Sanming method at 1500 +/-20 ℃ after molten iron is prepared: adding 1.3% of rare earth nodulizer, 0.7% of silicon-barium inoculant and 1.1% of covering agent, directionally adding by using a charging hopper during charging, timing by using a digital display timer, wherein the nodulizing time is 65-80 seconds, the nodulizing rate is more than 85%, and the nodulizing is qualified and can be cast.
The casting process adopts the stream inoculation of 0.3 percent rare earth stream inoculant, the casting temperature of a first box is 1390-1380 ℃, the temperature of the first box is measured when the temperature is lower than 1380 ℃, the temperature of a last box is not lower than 1350 ℃, a rapid metallographic test block and a spectrum test block are manufactured by a tail box of each package, the nodularity is not lower than 90 percent through the detection of a metallographic microscope, and the chemical components of the hub casting are controlled as follows:
carbon: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent.
If the composition range is not met, the composition is isolated, and the performance and the metallographic phase of the body are detected.
Off-line 2 hours after the product is poured, detecting the hub casting, and meeting the detection requirements of the body test block: the spheroidization rate is not lower than 85 percent, and the pearlite content is not higher than 5 percent.
And performing shot blasting treatment immediately after offline, removing the mechanical property and the metallographic phase of the tail box detection body in each furnace after shot blasting is completed, wherein the mechanical property detection is performed through a 10T tensile testing machine, and the metallographic phase is detected through a metallographic microscope.
Through detection: the tensile strength is more than or equal to 600Mpa, the yield strength is more than or equal to 450Mpa, the elongation is more than or equal to 12 percent, the spheroidization rate is more than or equal to 85 percent, the pearlite content is 2 to 5 percent, and free carbide content and phosphorus eutectic crystal are avoided.
The defects of shrinkage porosity and shrinkage cavity cannot be generated at any position. If one of the items fails to meet the above requirements, the product is discarded.
Cleaning and polishing: the casting flash is not more than 1.0mm, and the residue of a casting head is not more than 1.0 mm.
And (3) appearance detection: no obvious defects such as sand holes, air holes, cracks and the like.
Audio detection: and detecting by an audio detector, wherein the requirement is more than or equal to 3560, and if the requirement is not met, discarding.
And when the work is completely finished and qualified, boxing and shipping.
Compared with the conventional production method in the prior art, the method is characterized in that the method comprises the following steps of: the tensile strength is more than or equal to 600, the yield strength is more than or equal to 370, and the elongation is more than or equal to 10. Obviously, the method and the device not only omit the process steps, but also obtain better product performance.
The percentages in the present application are all mass percentages unless otherwise indicated.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (5)
1. A production method of as-cast thick large-section nodular cast iron is characterized by comprising the following steps: the method comprises the following steps:
(1) the ingredients comprise:
pig iron: benxi pig iron Q10;
scrap steel: carbon steel scrap, wherein: less than or equal to 0.4 percent of manganese,
(2) and spheroidizing: spheroidizing by adopting a Sanming method at 1500 +/-20 ℃ after molten iron is prepared: adding 1.2-1.4% of low rare earth nodulizer, 0.6-0.8% of silicon-barium inoculant and 1.0-1.2% of covering agent, wherein the nodulizing time is 65-80 seconds, the nodulizing rate is more than 85%,
(3) and casting: adopting stream inoculation of 0.2-0.4% rare earth inoculant, wherein the pouring temperature of a first box is 1390-,
wherein:
low rare earth nodulizer: the granularity is 5-20mm, and the silicon content is 44-46%; 0.50 to 0.60 percent of rare earth; the magnesium content is 5-7%; 0.5 to 1.5 percent of calcium; 0.70 to 0.80 percent of aluminum;
silicon-barium inoculant: the granularity is 1-3mm, the silicon content is 70-75 percent, and the barium content is 1-3 percent;
rare earth inoculant: the granularity is 0.2-0.6mm, and the silicon content is 70-75%; 2.0 to 2.5 percent of barium; calcium content is 1.50-1.60%; 1.2 to 1.6 percent of aluminum; 1.3 to 1.7 percent of rare earth;
covering agent: silicon steel sheets;
casting molding sand: the granularity of the mixture is 57-63,
(4) and the chemical component content of the formed casting is as follows: carbon: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent, and the balance of iron,
and (3) taking off the line after the casting is poured for 2 hours, performing shot blasting, removing a tail box in each furnace after completing shot blasting to detect the mechanical property and the metallographic property of the casting, and detecting: the tensile strength is more than or equal to 600Mpa, the yield strength is more than or equal to 450Mpa, the elongation is more than or equal to 12 percent, the spheroidization rate is more than or equal to 85 percent, the pearlite content is 2 to 5 percent, and free carbide content and phosphorus eutectic crystal are avoided.
2. The method for producing as-cast thick large-section spheroidal graphite cast iron according to claim 1, characterized in that: selecting a carburant to adjust the carbon content, wherein the carburant comprises the following steps: the low-sulfur carburant contains less than or equal to 0.05% of sulfur and less than or equal to 300ppm of N gas.
3. The method for producing as-cast thick large-section spheroidal graphite cast iron according to claim 1, characterized in that: adding a scrap returns into the mixture, wherein the ratio of the scrap returns to the scrap steel is 6: 4.
4. A cast product produced by the method for producing as-cast heavy and large section spheroidal graphite cast iron according to any one of the preceding claims, characterized in that: the chemical components of the product are as follows:
carbon: 3.00-3.20%; silicon: 3.80-4.20%; manganese: 0.20-0.30%; phosphorus: less than or equal to 0.05 percent; sulfur: 0.006-0.02%; tin: less than or equal to 0.01 percent; copper: less than or equal to 0.15 percent; chromium: less than or equal to 0.05 percent; the balance being iron.
5. The cast product of claim 4, wherein: the casting product is an engineering machinery hub casting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811621574.5A CN109609836B (en) | 2018-12-28 | 2018-12-28 | Production method of as-cast thick large-section nodular cast iron and cast product thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811621574.5A CN109609836B (en) | 2018-12-28 | 2018-12-28 | Production method of as-cast thick large-section nodular cast iron and cast product thereof |
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