CN114369756A - As-cast QT700-8 material and casting method and application thereof - Google Patents
As-cast QT700-8 material and casting method and application thereof Download PDFInfo
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- CN114369756A CN114369756A CN202210038784.1A CN202210038784A CN114369756A CN 114369756 A CN114369756 A CN 114369756A CN 202210038784 A CN202210038784 A CN 202210038784A CN 114369756 A CN114369756 A CN 114369756A
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- 238000005266 casting Methods 0.000 title claims abstract description 87
- 239000000463 material Substances 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 48
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 275
- 229910052742 iron Inorganic materials 0.000 claims abstract description 129
- 238000011081 inoculation Methods 0.000 claims abstract description 37
- 239000000126 substance Substances 0.000 claims abstract description 29
- 239000002994 raw material Substances 0.000 claims abstract description 17
- 238000010079 rubber tapping Methods 0.000 claims abstract description 16
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 12
- 239000000956 alloy Substances 0.000 claims abstract description 12
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 11
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 11
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 11
- 229910052802 copper Inorganic materials 0.000 claims abstract description 10
- 238000001514 detection method Methods 0.000 claims abstract description 10
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 10
- 229910052702 rhenium Inorganic materials 0.000 claims abstract description 10
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 8
- 238000002844 melting Methods 0.000 claims abstract description 4
- 230000008018 melting Effects 0.000 claims abstract description 4
- 239000002054 inoculum Substances 0.000 claims description 55
- 229910000805 Pig iron Inorganic materials 0.000 claims description 37
- 239000007788 liquid Substances 0.000 claims description 29
- 239000011777 magnesium Substances 0.000 claims description 27
- 239000004576 sand Substances 0.000 claims description 27
- UVGLBOPDEUYYCS-UHFFFAOYSA-N silicon zirconium Chemical compound [Si].[Zr] UVGLBOPDEUYYCS-UHFFFAOYSA-N 0.000 claims description 23
- -1 aluminum-silicon-calcium Chemical compound 0.000 claims description 21
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 19
- 239000003795 chemical substances by application Substances 0.000 claims description 18
- 239000002893 slag Substances 0.000 claims description 18
- 229910000831 Steel Inorganic materials 0.000 claims description 17
- 239000010959 steel Substances 0.000 claims description 17
- 150000002910 rare earth metals Chemical class 0.000 claims description 14
- MKPXGEVFQSIKGE-UHFFFAOYSA-N [Mg].[Si] Chemical compound [Mg].[Si] MKPXGEVFQSIKGE-UHFFFAOYSA-N 0.000 claims description 13
- 230000001681 protective effect Effects 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 10
- 238000007599 discharging Methods 0.000 claims description 10
- 239000011575 calcium Substances 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 5
- 239000010451 perlite Substances 0.000 claims description 4
- 235000019362 perlite Nutrition 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 3
- 229910001141 Ductile iron Inorganic materials 0.000 abstract description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 23
- 238000003723 Smelting Methods 0.000 description 21
- 229910002804 graphite Inorganic materials 0.000 description 19
- 239000010439 graphite Substances 0.000 description 19
- 230000008569 process Effects 0.000 description 14
- 239000000843 powder Substances 0.000 description 9
- 239000000440 bentonite Substances 0.000 description 7
- 229910000278 bentonite Inorganic materials 0.000 description 7
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 7
- 239000003245 coal Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000003110 molding sand Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 229910001018 Cast iron Inorganic materials 0.000 description 5
- 229910001562 pearlite Inorganic materials 0.000 description 5
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052729 chemical element Inorganic materials 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000005496 eutectics Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000005087 graphitization Methods 0.000 description 2
- 235000000396 iron Nutrition 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005562 fading Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002006 petroleum coke Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 230000002087 whitening effect Effects 0.000 description 1
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/22—Moulds for peculiarly-shaped castings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/10—Making spheroidal graphite cast-iron
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/10—Making spheroidal graphite cast-iron
- C21C1/105—Nodularising additive agents
-
- 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
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention relates to an as-cast QT700-8 material, a casting method and application thereof, and relates to the technical field of casting processes. Melting the raw materials into molten iron, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% -0.03 wt%; controlling the furnace temperature to 1480-1520 ℃, tapping the molten iron, spheroidizing inoculation, and stream inoculation during casting to obtain the as-cast QT700-8 material. The casting process provided by the invention is simple, the cost is lower, the consistency of the performance of the parts is better, and the problem that the strength and the elongation of the nodular cast iron are difficult to be considered at the same time is solved.
Description
Technical Field
The invention relates to the technical field of commercial vehicle chassis part manufacturing, in particular to an as-cast QT700-8 material and a casting method and application thereof.
Background
Automobile chassis parts and security parts are main components of automobile running, and the parts need to bear heavy load, so that the running safety of the automobile is guaranteed anytime and anywhere. In order to meet the requirements of load-carrying vehicles and passenger vehicles, the material quality of castings is gradually changed from original QT400-15 and QT450-10 ferrite ductile irons to mixed matrixes such as QT500-7 and QT600-3 and pearlite ductile irons with higher marks.
The strength and plasticity of the ductile iron material have great influence on the service life of the casting, the high cycle fatigue failure of the casting mainly depends on the strength of the casting, and the low cycle fatigue failure mainly depends on the plasticity of the casting. Ductile iron cannot have both strength and toughness to some extent. And often have higher requirements on the strength and elongation of the material when the part is used. Therefore, the key point is how to improve the elongation of the cast material of the casting under the condition of ensuring high strength, which is the difficulty of expanding the application range of the cast nodular cast iron. At present, in the prior art, the performance of nodular cast iron is further improved mainly by adding alloy elements into the traditional nodular cast iron material, but the mechanical property is improved to a limited extent, the strength and the toughness cannot be both achieved to a certain extent, and particularly, the higher the strength is, the harder the toughness is to be improved.
Chinese patent document No. 201710003893.9 discloses a production method of high-strength and high-toughness as-cast QT700-10, which comprises the following steps: (1) electric furnace smelting (2), spheroidizing inoculation (3), secondary inoculation (4) and pouring, and the obtained chemical components are as follows by mass percent: c3.6-3.8 wt%, Si 2.1-2.7 wt%, P not more than 0.04 wt%, C +1/3(Si + P) 4.3-4.6 wt%, Mn 0.2-0.4 wt%, Cu 0.3-0.5 wt%, Cr not more than 0.05 wt%, Sn 0.013-0.02 wt%, AF Mn +2.4Cu +3.2Cr +20Sn 1.56-2.0 wt%, S0.0060.015 wt%, Mg0.025wt% 0.05 wt%, RE not more than 0.02 wt%, and the balance of Fe in-cast QT 700-10. The method has complex process, is difficult to prepare castings with complex and uneven wall thickness, and has poor consistency of part performance.
Chinese patent document with application number 201911245407.X discloses an as-cast high-strength high-elongation synthetic nodular cast iron and a preparation method thereof, wherein the performance requirements of the as-cast high-strength high-elongation synthetic nodular cast iron under the as-cast condition are that the tensile strength Rm is more than or equal to 700MPa, and the elongation A after fracture is more than or equal to 10 wt%; the material consists of the following elements in percentage by mass: c: 3.5 wt% -3.7 wt%, Si: 2.9-3.3 wt%, Mn less than or equal to 0.2 wt%, P less than or equal to 0.035 wt%, S less than or equal to 0.02 wt%, Cu: 0.5 wt% -0.7 wt%, Ni: 0.55-0.75 wt%, Mg: 0.030 wt% -0.065 wt%, and the balance of Fe and trace elements. The specific preparation method comprises the following steps: scrap steel and raw material pure iron are carburized to smelt a raw iron liquid in a medium-frequency induction furnace, then pretreatment, spheroidization and inoculation are carried out, and finally, casting is carried out, so that QT700-10 is realized under the as-cast condition. The method adopts a cast iron synthesis process, the addition of scrap steel is high, so that impurity elements are more, and the stability and consistency of mass production castings are difficult to ensure. The silicon element is added more, so that low-temperature brittleness is easy to occur, and the problem of part failure is easy to occur in a cold environment.
Chinese patent document with application number 201811389930.5 discloses a low-cost high-toughness as-cast QT700-10 and a preparation method thereof, wherein the as-cast QT700-10 comprises the following chemical elements in percentage by mass: c: 3.3 wt%, Si: 2.2 wt%, Mn: 0.30 wt%, P is less than or equal to 0.070 wt%, S is less than or equal to 0.030 wt%, Re: 0.055 wt%, Mg: 0.050 wt%, Cu: 0.5 wt%, Sb: 0.03 wt%, the balance being Fe. The preparation method comprises the steps of furnace burden proportioning, smelting process control, spheroidization, inoculation and the like. The method has narrow chemical components, is difficult to accurately control and is difficult to apply in large batch.
In addition, although the nodular cast iron casting with high strength and toughness is prepared in the prior art, the performance index of the nodular cast iron casting is the performance of a single casting test block (refer to GB/T1348-. Because the casting body does not have good cooling conditions and large risers for feeding, the material structure and compactness of the casting body are not superior to those of a single casting test block, and the performance of the casting body is lower than that of the single casting test block.
Disclosure of Invention
In order to improve the effective utilization rate of raw materials and simultaneously obtain a nodular cast iron casting with high strength and high toughness, the invention provides the following technical scheme:
in a first aspect, there is provided a method of casting an as-cast QT700-8 material, comprising the steps of:
melting the raw materials into molten iron, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities;
controlling the furnace temperature to 1480-1520 ℃, tapping molten iron, spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to a spheroidizing ladle bottom according to 0.7-1.0 wt% of each type of molten iron, then adding a silicon-zirconium inoculant to the spheroidizing ladle bottom according to 0.25-0.35 wt% of each type of molten iron, then covering pressing ladle scrap iron on the silicon-zirconium inoculant according to 0.5-0.8 wt% of each type of molten iron, then discharging molten iron for spheroidizing, scattering a slag collecting agent into the discharged molten iron for slagging off, and then covering a layer of slag collecting agent;
pouring the spheroidized iron liquid into a green sand mold at 1390-1420 ℃, adding an aluminum-silicon-calcium inoculant into the iron liquid of each mold according to 0.08-0.15 wt% of the iron liquid for stream inoculation, and naturally cooling to obtain the cast QT700-8 material.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the rare earth magnesium silicon nodulizer, the content of Mg element is 7-9 wt%, the content of Si element is 35-44 wt%, the content of Ca element is less than 2.5 wt%, the content of Re is 4-6 wt%, and the balance is Fe.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the silicon-zirconium inoculant, the content of Si element is 65-75 wt%, the content of Al element is 0.5-1.5 wt%, the content of Zr element is 3.0-7.0 wt%, and the balance is Fe.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the particle size of the silicon-zirconium inoculant is 0.7mm-3 mm.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the aluminum-silicon-calcium inoculant, the content of Si element is 45-55 wt%, the content of Al element is 4-6 wt%, and the content of Ca element is 1-2 wt%.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the granularity of the aluminum-silicon-calcium inoculant is 0.2mm-0.7 mm.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the raw materials comprise: 10-20 wt% of foundry returns, 60-80 wt% of pig iron and 10-20 wt% of scrap steel; the pig iron is Q10 pig iron or Q12 pig iron, and the scrap steel is briquetting scrap steel.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the slag collecting agent is perlite.
In a second aspect, the invention provides an application of the casting method of the as-cast QT700-8 material in an automobile chassis casting, wherein the automobile chassis casting is one or more of a fixed end bracket, a lifting lug end bracket, a supporting arm beam, a front lower protective bracket, a thrust rod bracket, a steering gear bracket, a balance shaft bracket and a balance bearing hub.
In a third aspect, the invention provides an as-cast QT700-8 material, which comprises the following chemical components: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities.
The invention has the following advantages and beneficial effects:
1. the invention refines graphite and strengthens a matrix by silicon-zirconium inoculation, silicon-aluminum-calcium inoculation and secondary inoculation and adjustment of alloy components, the spheroidization grade reaches 1-2 grade, and the graphite size keeps 6-8 grade; the tensile strength of the cast-state casting body can reach more than 700MPa, the elongation rate can reach more than 10%, and the problem that the strength and the toughness of the nodular cast iron cannot be improved simultaneously is solved.
2. According to the casting method of the as-cast QT700-8 material, provided by the invention, the strength and the elongation rate of the as-cast product can meet requirements without further heat treatment, so that the production efficiency is greatly improved, and the production cost is reduced.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to data in the embodiments of the present invention, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In order to realize the effects of stable and consistent mass production performance of castings and small quality fluctuation of the castings, the invention controls the chemical elements, the smelting process, the spheroidizing process, the pouring conditions and the like of raw materials as follows:
1. chemical elements:
c element:
in order to improve the fluidity of the ductile cast iron liquid and reduce the shrinkage cavity defect of the casting, and ensure the quantity and the shape of graphite nodules to be round, the content of the C element of the ductile cast iron should be kept within a certain range. The content of C is high, the graphite in the cast iron becomes coarse and the quantity is increased, and the mechanical property is reduced; the C element content is less, so that the contraction tendency of the casting is increased, and the compactness of the casting is influenced. In the invention, the content of the C element is increased to be within the range of 3.5-3.9 wt%, and further, the content of the C element is controlled to be within the range of 3.5-3.8 wt%.
Si element:
generally, in order to improve the tensile strength of the material, the content of Si element needs to be increased for solid solution strengthening; as the content of the Si element increases, the content of pearlite in the matrix is gradually reduced, the content of ferrite is increased, and the brittle transition temperature of the casting is increased due to the excessively high content of the Si element. In order to ensure that the metallographic structure of the cast iron has ideal graphite quantity and ferrite content, the invention increases the content of the Si element as much as possible, but the content of the Si element is controlled not to be too high. In the invention, the content of the Si element is controlled within the range of 2.2 wt% -2.8 wt%, and the content of the Si element in the thick and large casting is limited.
Mn element:
the element can promote the formation of pearlite, thereby improving the mechanical property of the material. The content of Mn element is low, and the content of ferrite in the matrix is high; the content of Mn element is high, spherical graphite appears in the structure, and carbide is increased. In the invention, in order to obtain higher strength and elongation, the content range of Mn element is selected to be 0.2-0.4 wt%.
And (2) element S:
the S element and spheroidizing elements (mainly Mg and Re) have great affinity, and the more the original molten iron contains S, the more spheroidizing agent is consumed, and the generation tendency of scum is increased. The content of the S element is controlled within 0.015wt percent.
P element:
the P element is generally considered as a harmful element, and too much P element can form phosphorus eutectic, reduce the toughness of the material and make castings easy to have phenomena of shrinkage porosity and cold cracking, so the content of the P element is generally controlled within 0.03 wt%, and further the content of the P element is generally controlled within 0.025 wt%.
Cu element:
the Cu element promotes graphitization in cast iron eutectic solidification, and can reduce the tendency of whitening. The formation of pearlite is promoted during the eutectoid process, and the section sensitivity can be reduced. In order to ensure that the casting has good strength and elongation, the content of the Cu element is controlled within 0.4-0.6 wt%.
Ni element:
ni element, which is a graphitization element, reduces the tendency to white peeling, and functions as 1/3-1/4 of Si element. The Ni element is soluble in ferrite to perform solid solution strengthening, and increases and refines pearlite. Within a certain content range, the Ni element can improve the mechanical property of the nodular cast iron and has small influence on the elongation. The Ni content of the invention is controlled within the range of 0.4wt percent to 0.8wt percent.
Mg element, rare earth element Re:
mg and rare earth elements can inhibit the formation of flake graphite, poor spheroidization can occur when the content is low, the chilling tendency and the shrinkage tendency can be increased when the content is higher, and the production cost is increased. Mg can improve the roundness of graphite, and rare earth elements can eliminate the influence of impurity elements. The addition of Mg element and rare earth element is related to chemical components (especially S element content and impurity element content), spheroidizing process and inoculation process. According to the characteristics of the raw material control, spheroidizing process and inoculation process, the Mg content is strictly controlled to be 0.02 wt% -0.05 wt%, and the rare earth element content is strictly controlled to be 0.01 wt% -0.03 wt%.
2. And (3) spheroidizing process:
inoculation treatment: by adopting the mode of silicon-zirconium inoculation and silicon-aluminum-calcium inoculation, the silicon-zirconium inoculant has stronger anti-fading capability and is beneficial to graphite spheroidization, and the silicon-aluminum-calcium inoculant can increase the graphite core and increase the graphite quantity. By adopting the secondary inoculation process, the supercooling tendency can be effectively eliminated, the spherical graphite can be refined and increased, and the strength and the plasticity of the spherical graphite can be improved. The adding amount of the silicon-zirconium inoculant is 0.25-0.35 wt% of each type of molten iron, and the adding amount of the silicon-aluminum-calcium inoculant is 0.05-0.15 wt% of each type of molten iron.
Spheroidizing: mg and Re are spheroidizing elements in the spheroidizing process, the spheroidizing process of Mg is suitable for casting with wider range of wall thickness and carbon equivalent, but elements in cast iron such as Ti, B and the like can block the spheroidizing effect of Mg, and the spheroidizing effect can be neutralized by adding a small amount of rare earth with magnesium. The spheroidizing treatment of the invention takes Mg as the main component and a small amount of Re as the auxiliary component.
The carburant can increase the content of C in molten iron, and can be one or more of carburant pig iron, graphite, electrode powder, petroleum coke powder, charcoal powder and coke powder.
The slag collecting agent can collect and precipitate the slag, and only needs to be spread on the surface of molten iron, and specifically adopts perlite.
The stream inoculation is that the inoculant is crushed into fine particles, and the fine particles enter molten iron along with the flow of the molten iron to perform the inoculation effect in the process of pouring the molten iron into a ladle through a feeding device. In the invention, the stream inoculant is an aluminum-silicon-calcium inoculant with the granularity of 0.2-0.7mm, and the stream inoculant comprises the following chemical compositions: si: 45-55 wt%, Al: 4-6 wt%, Ca: 1 to 2 weight percent.
The green sand mold comprises the components of silica sand, coal powder, bentonite and the like, wherein the sand core of the green sand mold is coated sand, and the components of the green sand mold are silica sand and resin.
Based on the above inventive concept, the invention provides the following technical scheme:
in a first aspect, there is provided a method of casting an as-cast QT700-8 material, comprising the steps of:
melting the raw materials into molten iron, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities;
controlling the furnace temperature to 1480-1520 ℃, tapping molten iron, spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to a spheroidizing ladle bottom according to 0.7-1.0 wt% of each type of molten iron, then adding a silicon-zirconium inoculant to the spheroidizing ladle bottom according to 0.25-0.35 wt% of each type of molten iron, then covering pressing ladle scrap iron on the silicon-zirconium inoculant according to 0.5-0.8 wt% of each type of molten iron, then discharging molten iron for spheroidizing, scattering a slag collecting agent into the discharged molten iron for slagging off, and then covering a layer of slag collecting agent;
pouring the spheroidized iron liquid into a green sand mold at 1390-1420 ℃, adding an aluminum-silicon-calcium inoculant into the iron liquid of each mold according to 0.08-0.15 wt% of the iron liquid for stream inoculation, and naturally cooling to obtain the cast QT700-8 material.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the rare earth magnesium silicon nodulizer, the Mg content is 7 wt% -9 wt%, the Si content is 35 wt% -44 wt%, the Ca content is less than 2.5 wt%, the Re content is 4 wt% -6 wt%, and the balance is Fe.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the silicon-zirconium inoculant, the content of Si element is 65-75 wt%, the content of Al element is 0.5-1.5 wt%, the content of Zr element is 3.0-7.0 wt%, and the balance is Fe.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the particle size of the silicon-zirconium inoculant is 0.7mm-3 mm.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: in the aluminum-silicon-calcium inoculant, the content of Si element is 45-55 wt%, the content of Al element is 4-6 wt%, and the content of Ca element is 1-2 wt%.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the granularity of the aluminum-silicon-calcium inoculant is 0.2mm-0.7 mm.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the raw materials comprise: 10-20 wt% of foundry returns, 60-80 wt% of pig iron and 10-20 wt% of scrap steel; the pig iron is Q10 pig iron or Q12 pig iron, and the scrap steel is briquetting scrap steel.
On the basis of the casting method of the as-cast QT700-8 material, which is provided by the invention, the preferable technical scheme of the invention is as follows: the slag collecting agent is perlite.
In a second aspect, the invention provides an application of the casting method of the as-cast QT700-8 material in an automobile chassis casting, wherein the automobile chassis casting is one or more of a fixed end bracket, a lifting lug end bracket, a supporting arm beam, a front lower protective bracket, a thrust rod bracket, a steering gear bracket, a balance shaft bracket and a balance bearing hub.
In a third aspect, the invention provides an as-cast QT700-8 material, which comprises the following chemical components: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities.
The technical solutions of the present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited thereto. The rare earth magnesium silicon nodulizer adopted in the following examples has the following components of 7-9 wt% of Mg, 35-44 wt% of Si, less than or equal to 4 wt% of Ca, 6-8 wt% of Re and the balance of Fe; in the adopted silicon-zirconium inoculant, the content of Si element is 65-75 wt%, the content of Al element is 0.5-1.5 wt%, the content of Zr element is 3.0-7.0 wt%, and the balance is Fe, and the granularity of the silicon-zirconium inoculant is 0.7-3 mm; in the adopted aluminum-silicon-calcium inoculant, the content of Si element is 45-55 wt%, the content of Al element is 4-6 wt%, the content of Ca element is 1-2 wt%, and the granularity of the aluminum-silicon-calcium inoculant is 0.2-0.7 mm.
Example 1
The embodiment provides a front lower protective bracket casting method, which comprises the following steps:
(1) preparing raw materials according to the following weight percentages: 10 wt% of scrap returns, 80 wt% of pig iron and 10 wt% of scrap steel, wherein the pig iron is Q10 pig iron.
(2) Providing a green sand mold suitable for a front lower protective bracket of an automobile chassis: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a returned material and pig iron to a molten state, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: 3.54 wt% of C, 2.74 wt% of Si, 0.2 wt% of Mn, 0.56 wt% of Cu, 0.4 wt% of Ni, 0.025 wt% of P, 0.005 wt% of S, 0.029 wt% of Mg, 0.022 wt% of Re, and the balance of iron; controlling the tapping temperature to 1520 ℃, tapping the molten iron.
(4) Spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer with the grain diameter of 4-8mm into the bottom of a nodulizing ladle according to 0.7 wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.25 wt% of each type of molten iron, then covering pressing ladle scrap iron on the inoculant according to 0.5 wt% of each type of molten iron, then discharging the molten iron for nodulizing, after discharging, scattering a slag collecting agent into the molten iron for slagging off, and finally scattering a slag collecting agent for covering.
(5) Pouring: pouring the spheroidized iron liquid at 1420 ℃, and adding an aluminum-silicon-calcium inoculant into the iron liquid according to 0.15 wt% of each type of iron liquid for stream inoculation while pouring.
(6) And after natural cooling, taking the mold to obtain a front lower protective bracket casting.
The spheroidization grade of the front lower protective bracket body reaches 1 grade, the graphite size keeps 6 grades, the tensile strength is 720MPa, and the elongation is 11 wt%. The tensile strength of a single-cast Y-shaped test block (II-type test block in the standard GB/T1384-2009) of the front lower protective bracket is 731MPa, and the elongation is 15%.
Example 2
The embodiment provides a casting method of a thrust rod bracket, which comprises the following steps:
(1) preparing raw materials according to the following weight percentages: 15 wt% of foundry returns, 70 wt% of pig iron and 15 wt% of scrap steel, wherein the pig iron is Q12 pig iron;
(2) providing a green sand mold suitable for the automobile chassis thrust rod support: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a returned material and pig iron to a molten state, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: 3.70 wt% of C, 2.28 wt% of Si, 0.31 wt% of Mn, 0.49 wt% of Cu, 0.8 wt% of Ni, 0.015 wt% of P, 0.015 wt% of S, 0.036 wt% of Mg, 0.015 wt% of Re and the balance of iron; controlling the tapping temperature to be 1500 ℃, and tapping the molten iron.
(4) Spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to the bottom of a nodulizing ladle according to 0.9 wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.30 wt% of each type of molten iron, then covering press-coating scrap iron on the inoculant according to 0.7 wt% of each type of molten iron, then discharging the molten iron for nodulizing, and scattering a slag collecting agent into the discharged molten iron for covering.
(5) Pouring: pouring the spheroidized iron liquid at the temperature of 1400 ℃, and adding an aluminum-silicon-calcium inoculant into the iron liquid according to 0.10 wt% of each type of iron liquid during pouring to perform stream inoculation.
(6) And after natural cooling, taking the die to obtain a thrust rod bracket casting.
The spheroidization grade of the thrust rod support casting body reaches 2 grades, the graphite size keeps 7 grades, the tensile strength is 786MPa, and the elongation is 10%. The tensile strength of a single-cast Y-shaped test block (a type II test block in the standard GB/T1384-2009) of the thrust rod bracket casting is 774MPa, and the elongation is 13%.
Example 3
The embodiment provides a fixed end bracket casting method, which comprises the following steps:
(1) preparing raw materials according to the following weight percentages: 20 wt% of scrap returns, 60 wt% of pig iron and 20 wt% of scrap steel, wherein the pig iron is Q10 pig iron.
(2) Providing a green sand mold suitable for a front lower protective bracket of an automobile chassis: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a returned material and pig iron to a molten state, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: 3.78 wt% of C, 2.34 wt% of Si, 0.33 wt% of Mn, 0.45 wt% of Cu, 0.78 wt% of Ni, 0.022 wt% of P, 0.008 wt% of S, 0.048 wt% of Mg, 0.014 wt% of Re and the balance of iron; controlling the tapping temperature to 1480 ℃, and tapping the molten iron.
(4) Spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to the bottom of a nodulizing ladle according to 1.0 wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.35 wt% of each type of molten iron, then covering press-ladle scrap iron on the inoculant according to 0.8 wt% of each type of molten iron, then discharging the molten iron for nodulizing, and scattering a slag collecting agent into the discharged molten iron for covering.
(5) Pouring: pouring the spheroidized iron liquid at the temperature of 1390 ℃, and adding an aluminum-silicon-calcium inoculant into the iron liquid according to 0.05 wt% of each type of iron liquid during pouring to perform stream inoculation.
(6) And after natural cooling, taking the die to obtain a fixed end bracket casting.
The spheroidization grade of the bracket at the fixed end of the automobile chassis reaches 2 grades, the size of graphite keeps 8 grades, the tensile strength is 754MPa, and the elongation is 10%. The tensile strength of the fixed end bracket casting single-casting Y-shaped test block (II type test block in the standard GB/T1384-2009) is 761MPa, and the elongation is 14 percent.
TABLE 1 parts bulk chemistry and part Properties prepared in examples 1-3
Comparative example 1
The present comparative example provides a method of casting a front lower shield support, comprising the steps of:
(1) preparing raw materials according to the following weight percentages: 10 wt% of scrap returns, 80 wt% of pig iron and 10 wt% of scrap steel, wherein the pig iron is Q10 pig iron.
(2) Providing a green sand mold suitable for a front lower protective bracket of an automobile chassis: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a returned material and pig iron to a molten state, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: 3.52 wt% of C, 2.72 wt% of Si, 0.25 wt% of Mn, 0.59 wt% of Cu, 0.11 wt% of Ni, 0.028 wt% of P, 0.006 wt% of S, 0.039 wt% of Mg, 0.011 wt% of Re and the balance of iron; controlling the tapping temperature to 1520 ℃, tapping the molten iron.
(4) Spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to the bottom of a nodulizing ladle according to 0.7 wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.25 wt% of each type of molten iron, then covering press-coating scrap iron on the inoculant according to 0.5 wt% of each type of molten iron, then discharging the molten iron for nodulizing, and scattering a slag collecting agent into the discharged molten iron for covering.
(5) Pouring: pouring the spheroidized iron liquid at 1420 ℃, and adding an aluminum-silicon-calcium inoculant into the iron liquid according to 0.15 wt% of each type of iron liquid for stream inoculation while pouring.
(6) And after natural cooling, taking the mold to obtain a front lower protective bracket casting.
Compared with example 1, the chemical composition of the iron liquid is different: the addition amount of Ni in the lower protective bracket before the comparison is lower, the spheroidization grade of the material reaches 2 grade, the graphite size keeps 6 grade, the tensile strength of the body is 798MPa, the elongation is 6 percent, and the performance requirements of the material are not met.
Comparative example 2
The embodiment provides a thrust rod bracket casting method, which comprises the following steps:
(1) preparing raw materials according to the following weight percentages: 15 wt% of scrap returns, 70 wt% of pig iron and 15 wt% of scrap steel, wherein the pig iron is Q12 pig iron.
(2) Providing a green sand mold suitable for the automobile chassis thrust rod support: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a returned material and pig iron to a molten state, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: 3.60 wt% of C, 2.38 wt% of Si, 0.25 wt% of Mn, 0.52 wt% of Cu, 0.98 wt% of Ni, 0.016 wt% of P, 0.012 wt% of S, 0.026 wt% of Mg, 0.024 wt% of Re and the balance of iron. Controlling the tapping temperature to be 1500 ℃, and tapping the molten iron.
(4) Spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer into a nodulizing ladle bottom according to 0.9 wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.30 wt% of each type of molten iron, then covering press-ladle scrap iron on the inoculant according to 0.7 wt% of each type of molten iron, then discharging the molten iron for nodulizing, and scattering a slag collecting agent into the discharged molten iron for covering.
(5) Pouring: pouring the spheroidized iron liquid at the temperature of 1400 ℃, and adding an aluminum-silicon-calcium inoculant into the iron liquid according to 0.10 wt% of each type of iron liquid during pouring to perform stream inoculation.
(6) And after natural cooling, taking the die to obtain a thrust rod bracket casting.
Compared with the embodiment 2, the Ni element addition amount in the thrust rod bracket casting material of the comparative example is higher, the material spheroidization grade reaches grade 2, the graphite size keeps grade 7, the tensile strength of the body is 783MPa, the elongation is 9 wt%, but the mechanical property is not effectively improved. It is demonstrated that increased Ni content does not improve the performance of the inventive part and increases cost.
Comparative example 3
The embodiment provides a fixed end bracket casting method, which comprises the following steps:
(1) preparing raw materials according to the following weight percentages: 20 wt% of scrap returns, 60 wt% of pig iron and 20 wt% of scrap steel, wherein the pig iron is Q10 pig iron.
(2) Providing a green sand mold suitable for a front lower protective bracket of an automobile chassis: the molding sand is prepared from new sand, old sand, bentonite and coal powder.
(3) Smelting: smelting molten iron by using an intermediate frequency furnace, smelting a foundry returns and pig iron to a molten state, adding a carburant and an alloy according to a detection result of chemical components, and adjusting the chemical components of the molten iron to be 3.72 wt% of C, 2.40 wt% of Si, 0.31 wt% of Mn, 0.47 wt% of Cu, 0.75 wt% of Ni, 0.021 wt% of P, 0.008 wt% of S, 0.041 wt% of Mg, 0.018 wt% of Re and the balance of iron; controlling the tapping temperature to 1480 ℃, and tapping the molten iron.
(4) Spheroidizing inoculation: firstly adding a rare earth magnesium silicon nodulizer to the bottom of a nodulizing ladle according to 1.0 wt% of each type of molten iron, then adding a common FeSi75 inoculant according to 0.35 wt% of each type of molten iron, then covering pressing scrap iron on the inoculant according to 0.8 wt% of each type of molten iron, then discharging the molten iron for nodulizing, and finally spraying a slag collecting agent to cover the discharged molten iron.
(5) Pouring: pouring the spheroidized iron liquid at the temperature of 1390 ℃, and adding a common FeSi75 inoculant in an amount of 0.05 wt% of each type of iron liquid for stream inoculation.
(6) And after natural cooling, taking the die to obtain a fixed end bracket casting.
Compared with example 3, the inoculant in the spheroidizing inoculation step of the preparation method of the comparative example is the common FeSi75 inoculant added in an amount of 0.35 wt% of each type of molten iron, the stream inoculation in the pouring step is the common FeSi75 inoculant added in an amount of 0.05 wt% of each type of molten iron, and other preparation steps are carried out according to example 3. The spheroidization grade of the obtained fixed end bracket material reaches 3 grades, the graphite size is kept 6 grades, the tensile strength of the body is 685MPa, the elongation is 4 wt%, and the performance requirements of the invention on the material are not met. It is demonstrated that the strength and toughness of the part can be improved with the inoculant combination of example 3.
TABLE 2 parts prepared in comparative examples 1-3 have bulk chemical composition and part properties
The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A casting method of an as-cast QT700-8 material is characterized by comprising the following steps:
melting the raw materials into molten iron, adding a carburant and an alloy according to a chemical component detection result, and adjusting the chemical components of the molten iron as follows: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities;
controlling the furnace temperature to 1480-1520 ℃, tapping molten iron, spheroidizing inoculation: firstly, adding a rare earth magnesium silicon nodulizer to a spheroidizing ladle bottom according to 0.7-1.0 wt% of each type of molten iron, then adding a silicon-zirconium inoculant to the spheroidizing ladle bottom according to 0.25-0.35 wt% of each type of molten iron, then covering pressing ladle scrap iron on the silicon-zirconium inoculant according to 0.5-0.8 wt% of each type of molten iron, then discharging molten iron for spheroidizing, scattering a slag collecting agent into the discharged molten iron for slagging off, and then covering a layer of slag collecting agent;
pouring the spheroidized iron liquid into a green sand mold at 1390-1420 ℃, adding an aluminum-silicon-calcium inoculant into the iron liquid of each mold according to 0.08-0.15 wt% of the iron liquid for stream inoculation, and naturally cooling to obtain the cast QT700-8 material.
2. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: in the rare earth magnesium silicon nodulizer, the content of Mg element is 7-9 wt%, the content of Si element is 35-44 wt%, the content of Ca element is less than 2.5 wt%, the content of Re is 4-6 wt%, and the balance is Fe.
3. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: in the silicon-zirconium inoculant, the content of Si element is 65-75 wt%, the content of Al element is 0.5-1.5 wt%, the content of Zr element is 3.0-7.0 wt%, and the balance is Fe.
4. Casting process of as-cast QT700-8 material according to claim 1 or 3, characterized in that: the particle size of the silicon-zirconium inoculant is 0.7mm-3 mm.
5. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: in the aluminum-silicon-calcium inoculant, the content of Si element is 45-55 wt%, the content of Al element is 4-6 wt%, and the content of Ca element is 1-2 wt%.
6. Casting process of as-cast QT700-8 material according to claim 1 or 5, characterized in that: the granularity of the aluminum-silicon-calcium inoculant is 0.2mm-0.7 mm.
7. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: the raw materials comprise: 10-20 wt% of foundry returns, 60-80 wt% of pig iron and 10-20 wt% of scrap steel; the pig iron is Q10 pig iron or Q12 pig iron, and the scrap steel is briquetting scrap steel.
8. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: the slag collecting agent is perlite.
9. The application of the casting method of the as-cast QT700-8 material as claimed in any of claims 1 to 8 to automobile chassis castings is characterized in that: the automobile chassis casting is one or more of a fixed end support, a lifting lug end support, a supporting arm beam, a front lower protective support, a thrust rod support, a steering engine support, a balance shaft support and a balance bearing hub.
10. An as-cast QT700-8 material is characterized by comprising the following chemical components: c: 3.5-3.9 wt%, Si: 2.2-2.8 wt%, Mn: 0.2 wt% to 0.4 wt%, Cu: 0.4 wt% -0.6 wt%, Ni: 0.4-0.8 wt%, S is less than or equal to 0.015 wt%, P is less than 0.03 wt%, Mg: 0.02 wt% -0.05 wt%, Re: 0.01 wt% to 0.03 wt%, the balance being Fe and unavoidable impurities.
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| CN110964974A (en) * | 2019-12-07 | 2020-04-07 | 湖北三环铸造股份有限公司 | As-cast high-strength high-elongation synthetic nodular cast iron and preparation method thereof |
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| JP2008156688A (en) * | 2006-12-22 | 2008-07-10 | Jfe Steel Kk | High strength spheroidal graphite cast iron |
| CN103343279A (en) * | 2013-06-28 | 2013-10-09 | 上海圣德曼铸造有限公司 | As-cast pearlite ductile iron material for crankshaft, and preparation method of the same |
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| CN111771002A (en) * | 2017-12-29 | 2020-10-13 | 埃尔凯姆公司 | Cast iron inoculant and method for producing a cast iron inoculant |
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