CN114369756B - 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 PDF

Info

Publication number
CN114369756B
CN114369756B CN202210038784.1A CN202210038784A CN114369756B CN 114369756 B CN114369756 B CN 114369756B CN 202210038784 A CN202210038784 A CN 202210038784A CN 114369756 B CN114369756 B CN 114369756B
Authority
CN
China
Prior art keywords
cast
iron
content
molten iron
silicon
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210038784.1A
Other languages
Chinese (zh)
Other versions
CN114369756A (en
Inventor
袁福安
康明
金通
霍卯田
涂欣达
晏克春
郭冷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dongfeng Commercial Vehicle Co Ltd
Original Assignee
Dongfeng Commercial Vehicle Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dongfeng Commercial Vehicle Co Ltd filed Critical Dongfeng Commercial Vehicle Co Ltd
Priority to CN202210038784.1A priority Critical patent/CN114369756B/en
Publication of CN114369756A publication Critical patent/CN114369756A/en
Application granted granted Critical
Publication of CN114369756B publication Critical patent/CN114369756B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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

Landscapes

  • 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:0.2wt% to 0.4wt%, cu:0.4wt% -0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, re:0.01wt% -0.03wt%; controlling the furnace temperature to 1480-1520 ℃, tapping the molten iron, spheroidizing inoculation, and stream inoculation during pouring to obtain a cast QT700-8 material. The casting process provided by the invention is simple, has lower cost and better consistency of the performance of parts, and solves the problem that the strength and the elongation of the nodular cast iron are difficult to consider at the same time.

Description

As-cast QT700-8 material and casting method and application thereof
Technical Field
The invention relates to the technical field of manufacturing of chassis parts of commercial vehicles, 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. Spheroidal graphite cast iron cannot have both strength and toughness to some extent. And often have higher requirements on the strength and the 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 with application number 201710003893.9 discloses a production method of high-strength and high-toughness as-cast QT700-10, which comprises the following steps: the method comprises the following steps of (1) electric furnace smelting (2), spheroidizing inoculation (3), secondary inoculation (4) pouring, and the obtained chemical components in percentage by mass: c3.6-3.8 wt%, si 2.1-2.7 wt%, P is less than or equal to 0.04wt%, and the carbon equivalent CE = C +1/3 (Si + P) = 4.3-4.6 wt%, mn 0.2-0.4 wt%, cu 0.3-0.5 wt%, cr is less than or equal to 0.05wt%, sn 0.013-0.02 wt%, AF = Mn +2.4Cu 3.2Cr +20Sn =1.56wt% -2.0 wt%, S0.006wt% -0.015 wt%, mg0.025wt% -0.05wt%, RE is less than or equal to 0.02wt%, and the balance is Fe as-cast QT700-10. The method has the disadvantages of complex process, difficulty in preparing complex castings with uneven wall thickness and 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 are met under the as-cast condition that the tensile strength Rm is more than or equal to 700MPa, and the elongation A after fracture is more than or equal to 10wt%; the material consists of the following elements in percentage by mass: c:3.5wt% -3.7 wt%, si: 2.9-3.3 wt%, mn less than or equal to 0.2wt%, P less than or equal to 0.035wt%, S less than or equal to 0.02wt%, cu:0.5wt% -0.7 wt%, ni: 0.55-0.75 wt%, mg:0.030wt% -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 molten raw iron 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:3.3wt%, si:2.2wt%, mn:0.30wt%, P is less than or equal to 0.070wt%, S is less than or equal to 0.030wt%, re:0.055wt%, mg:0.050wt%, cu:0.5wt%, sb:0.03wt%, and the balance 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 ductile iron castings with high strength and toughness are prepared in the prior art, the performance index of the ductile iron castings is the performance of a single casting block (refer to GB/T1348-2009), and the ductile iron castings cannot represent the performance of the casting body. 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 ductile 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: 0.2-0.4 wt%, cu:0.4wt% -0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, re:0.01wt% to 0.03wt%, 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 the bottom of a spheroidizing ladle according to 0.7-1.0 wt% of each type of molten iron, then adding a silicon-zirconium inoculant to the bottom of the spheroidizing ladle according to 0.25-0.35 wt% of each type of molten iron, then covering press 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 7wt% -9wt%, the content of Si element is 35wt% -44wt%, the content of Ca element is less than 2.5wt%, the content of Re is 4wt% -6wt%, 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-3mm.
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-0.7mm.
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: 0.2-0.4 wt%, cu:0.4wt% -0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, re:0.01wt% to 0.03wt%, 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 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 making any creative effort based on the embodiments in the present invention, belong to the protection 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 chemical elements of raw materials, a smelting process, a spheroidizing process, pouring conditions and the like as follows:
1. chemical elements:
c element:
in order to improve the fluidity of the ductile cast iron liquid and reduce the shrinkage 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. The content of the C element is increased to be within the range of 3.5wt% -3.9wt%, and further, the content of the C element is controlled to be within the range of 3.5wt% -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 improves 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 2.2wt% -2.8wt%, 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 0.03wt%, 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 eutectoid, 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, can reduce the tendency to white peeling, and functions as 1/3 to 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 be caused 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 0.02wt% -0.05wt%, and the rare earth element content is strictly controlled to be 0.01wt% -0.03 wt%.
2. And (3) a 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 the graphite quantity. By adopting the secondary inoculation process, the supercooling tendency can be effectively eliminated, the spherical graphite is refined and increased, and the strength and the plasticity of the spherical graphite are 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 recarburizer can improve the content of C in molten iron, and can be one or more of recarburized 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 to crush an inoculant 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: 0.2-0.4 wt%, cu:0.4wt% -0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, re:0.01wt% to 0.03wt%, 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 7wt% -9wt%, the Si content is 35wt% -44wt%, the Ca content is less than 2.5wt%, the Re content is 4wt% -6wt%, 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-3mm.
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-0.7mm.
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:0.2wt% to 0.4wt%, cu:0.4wt% to 0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, re:0.01wt% to 0.03wt%, 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 4wt% 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: 10wt% of foundry returns, 80wt% of pig iron and 10wt% 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: 3.54wt% of C, 2.74wt% of Si, 0.2wt% of Mn, 0.56wt% of Cu, 0.4wt% of Ni, 0.025wt% of P, 0.005wt% of S, 0.029wt% of Mg, 0.022wt% of Re, and the balance of Fe; 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 0.7wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.25wt% of each type of molten iron, then covering pressing ladle scrap iron on the inoculant according to 0.5wt% 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 the temperature of 1420 ℃, and adding an aluminum-silicon-calcium inoculant into the molten iron according to 0.15wt% of each type of molten iron for stream inoculation during 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 grade 1, the graphite size is kept at grade 6, the tensile strength is 720MPa, and the elongation is 11wt%. 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: 15wt% of foundry returns, 70wt% of pig iron and 15wt% 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: 3.70wt% of C, 2.28wt% of Si, 0.31wt% of Mn, 0.49wt% of Cu, 0.8wt% of Ni, 0.015wt% of P, 0.015wt% of S, 0.036wt% of Mg, 0.015wt% 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 0.9wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.30wt% of each type of molten iron, then covering press-coating scrap iron on the inoculant according to 0.7wt% 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 0.10wt% 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-casting Y-shaped test block (II type test block in GB/T1384-2009) of a thrust rod support casting is 774MPa, and the elongation is 13%.
Example 3
The embodiment provides a casting method of a fixed end bracket, which comprises the following steps:
(1) Preparing raw materials according to the following weight percentages: 20wt% of foundry returns, 60wt% of pig iron and 20wt% 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: 3.78wt% of C, 2.34wt% of Si, 0.33wt% of Mn, 0.45wt% of Cu, 0.78wt% of Ni, 0.022wt% of P, 0.008wt% of S, 0.048wt% of Mg, 0.014wt% of Re and the balance of iron; controlling the tapping temperature to be 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 1.0wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.35wt% of each type of molten iron, then covering press-ladle scrap iron on the inoculant according to 0.8wt% 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 molten iron at the same time of pouring according to 0.05wt% of each type of molten iron for stream inoculation.
(6) And after natural cooling, taking the die to obtain a fixed end bracket casting.
The spheroidization grade of the support at the fixed end of the automobile chassis reaches 2 grades, the size of graphite is kept 8 grades, the tensile strength is 754MPa, and the elongation is 10 percent. The tensile strength of a single-casting Y-shaped test block (II type test block in GB/T1384-2009) of the fixed end support casting is 761MPa, and the elongation is 14%.
Table 1 bulk chemical composition and part properties of parts prepared in examples 1-3
Figure BDA0003469266760000151
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 percentage: 10wt% of foundry returns, 80wt% of pig iron and 10wt% 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: 3.52wt% of C, 2.72wt% of Si, 0.25wt% of Mn, 0.59wt% of Cu, 0.11wt% of Ni, 0.028wt% of P, 0.006wt% of S, 0.039wt% of Mg, 0.011wt% of Re and the balance of iron; controlling the tapping temperature to 1520 ℃, tapping the molten iron.
(4) Spheroidizing inoculation: firstly adding rare earth magnesium silicon nodulizer to the bottom of a spheroidizing ladle according to 0.7wt% of each type of molten iron, then adding silicon zirconium inoculant according to 0.25wt% of each type of molten iron, then covering press ladle scrap iron on the inoculant according to 0.5wt% of each type of molten iron, then discharging the molten iron for spheroidizing, and after discharging, scattering a slag collecting agent into the 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 0.15wt% 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: 15wt% of foundry returns, 70wt% of pig iron and 15wt% 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 foundry returns 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: 3.60wt% of C, 2.38wt% of Si, 0.25wt% of Mn, 0.52wt% of Cu, 0.98wt% of Ni, 0.016wt% of P, 0.012wt% of S, 0.026wt% of Mg, 0.024wt% 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 0.9wt% of each type of molten iron, then adding a silicon-zirconium inoculant according to 0.30wt% of each type of molten iron, then covering press-ladle scrap iron on the inoculant according to 0.7wt% 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 molten iron according to 0.10wt% of each type for stream inoculation during pouring.
(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 9wt%, 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 casting method of a fixed end bracket, which comprises the following steps:
(1) Preparing raw materials according to the following weight percentages: 20wt% of foundry returns, 60wt% of pig iron and 20wt% 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 3.72wt% of C, 2.40wt% of Si, 0.31wt% of Mn, 0.47wt% of Cu, 0.75wt% of Ni, 0.021wt% of P, 0.008wt% of S, 0.041wt% of Mg, 0.018wt% of Re and the balance of iron; controlling the tapping temperature to be 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 1.0wt% of each type of molten iron, then adding a common FeSi75 inoculant according to 0.35wt% of each type of molten iron, then covering pressing scrap iron on the inoculant according to 0.8wt% 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 0.05wt% 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 the example 3, the inoculant in the spheroidizing inoculation step of the preparation method of the comparative example is the common FeSi75 inoculant in an adding amount of 0.35wt% of each type of molten iron, the stream inoculation in the pouring step is the common FeSi75 inoculant in an adding amount of 0.05wt% of each type of molten iron, and other preparation steps are carried out according to the example 3. The spheroidization grade of the obtained fixed end bracket material reaches 3 grades, the graphite size keeps 6 grades, the tensile strength of the body is 685MPa, the elongation is 4wt%, and the performance requirements of the invention on the material are not met. The strength and toughness of the parts are improved by using the inoculant combination of example 3.
Table 2 bulk chemical composition and part properties of parts prepared in comparative examples 1-3
Figure BDA0003469266760000191
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 (8)

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:0.2wt% to 0.4wt%, cu:0.4wt% to 0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, RE:0.01wt% to 0.03wt%, 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; 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;
pouring spheroidized iron liquid into a green sand mold at 1390-1420 ℃, adding an aluminum-silicon-calcium inoculant in an amount of 0.08-0.15 wt% of each type of iron liquid for stream inoculation, and naturally cooling to obtain a cast QT700-8 material; 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%.
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 7wt% -9wt%, the content of Si element is 35wt% -44wt%, the content of Ca element is less than 2.5wt%, the content of RE element is 4wt% -6wt%, and the balance is Fe.
3. The casting process of an as-cast QT700-8 material according to claim 1, characterized in that: the particle size of the silicon-zirconium inoculant is 0.7mm-3mm.
4. Casting process of as-cast QT700-8 material according to claim 1, characterized in that: the granularity of the aluminum-silicon-calcium inoculant is 0.2mm-0.7mm.
5. 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.
6. The casting process of an as-cast QT700-8 material according to claim 1, characterized in that: the slag collecting agent is perlite.
7. The use of the method for casting as-cast QT700-8 material of any of claims 1 to 6 on castings of automotive chassis, 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.
8. An as-cast QT700-8 material prepared by a casting method of the as-cast QT700-8 material as claimed in any of claims 1 to 6, characterized in that the as-cast QT700-8 material comprises the following chemical components: c: 3.5-3.9 wt%, si: 2.2-2.8 wt%, mn:0.2wt% to 0.4wt%, cu:0.4wt% -0.6wt%, ni: 0.4-0.8 wt%, S is less than or equal to 0.015wt%, P is less than 0.03wt%, mg:0.02wt% -0.05wt%, RE:0.01wt% to 0.03wt%, and the balance of Fe and unavoidable impurities.
CN202210038784.1A 2022-01-13 2022-01-13 As-cast QT700-8 material and casting method and application thereof Active CN114369756B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210038784.1A CN114369756B (en) 2022-01-13 2022-01-13 As-cast QT700-8 material and casting method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210038784.1A CN114369756B (en) 2022-01-13 2022-01-13 As-cast QT700-8 material and casting method and application thereof

Publications (2)

Publication Number Publication Date
CN114369756A CN114369756A (en) 2022-04-19
CN114369756B true CN114369756B (en) 2023-01-24

Family

ID=81143298

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210038784.1A Active CN114369756B (en) 2022-01-13 2022-01-13 As-cast QT700-8 material and casting method and application thereof

Country Status (1)

Country Link
CN (1) CN114369756B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115287524A (en) * 2022-07-08 2022-11-04 东风商用车有限公司 Heavy-duty commercial vehicle diesel engine rocker arm and manufacturing method and application thereof

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4835424B2 (en) * 2006-12-22 2011-12-14 Ｊｆｅスチール株式会社 High strength spheroidal graphite cast iron
CN103343279B (en) * 2013-06-28 2015-11-18 上海圣德曼铸造有限公司 A kind of bent axle as-cast pearlitic ductile iron material and preparation method thereof
CN103981434B (en) * 2014-05-28 2015-12-02 河南理工大学 A kind of preparation method of high tough spheroidal graphite cast iron
NO20172065A1 (en) * 2017-12-29 2019-07-01 Elkem Materials Cast iron inoculant and method for production of cast iron inoculant
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

Also Published As

Publication number Publication date
CN114369756A (en) 2022-04-19

Similar Documents

Publication Publication Date Title
CN101660097B (en) Wear-resisting alloy steel with high boron, high chrome and low carbon and preparation method thereof
CN109371315B (en) High-strength vermicular graphite cast iron and preparation method thereof
CN101942619B (en) Glass mould material of alloy cast iron and preparation method thereof
CN102747268B (en) High-strength high-ductility nodular cast iron and manufacturing method thereof
CN102071351B (en) Vermicularizing treatment process of vanadium-titanium vermicular graphite cast iron
CN102383027B (en) Preparation method of nodular cast iron
CN103320680A (en) Nodular cast iron and preparation method thereof
CN102400032B (en) Large-cross-section nodular cast iron
CN112853025A (en) Casting process of nodular iron casting for wind power
CN102071352A (en) Vanadium-titanium vermicular cast iron brake drum and preparation method thereof
CN104233052A (en) Chromium, molybdenum and copper alloy cast iron braking drum and preparation method thereof
CN105316563A (en) Inoculants, preparation method thereof and application in smelting of nodular cast iron
CN114381649B (en) High-strength high-toughness nodular cast iron material and casting method thereof
CN102382924B (en) Preparation method of nodulizing agent for nodular cast iron
CN111961954A (en) Preparation method of as-cast mixed matrix QT500-14 nodular cast iron
CN102392094B (en) Spheroidizing agent for spheroidal graphite cast iron, and preparation method thereof
CN114369756B (en) As-cast QT700-8 material and casting method and application thereof
CN110129665A (en) A kind of as cast condition sand casting niobium-containing high-strength high-ductility ductile cast iron material and preparation method thereof
CN110066959B (en) High-strength low-sulfur high-manganese inoculated gray cast iron material and smelting and pouring process thereof
CN111455263A (en) Environment-friendly low-temperature nodular cast iron produced by using low-rare earth alloy and production process thereof
CN102373365B (en) Large-section nodular cast iron
CN113088804A (en) Cast high-strength ductile iron and manufacturing method thereof
CN107723582B (en) High-aluminum high-temperature-resistant nodular cast iron containing molybdenum and chromium elements and preparation method thereof
CN105349878B (en) Antimony-bearing spheroidal graphite cast iron and production method thereof
CN110551937B (en) Casting method of large-cylinder-diameter cylinder sleeve for marine low-speed diesel engine

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant