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Preparing method for as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron

A ductile iron and matrix technology, which is applied in the field of preparation of as-cast mixed matrix QT500-14 ductile iron, can solve the problems of long melt processing process, unstable elongation of the attached cast test block, and complicated operation, and achieves the promotion of magnesium absorption. rate, good spheroidization effect, and the effect of improving fluidity

Pending Publication Date: 2020-11-20
SHANGHAI TOBACCO MACHINERY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the method disclosed in the Chinese invention patent application CN107022712A "A Manufacturing Method for Shaft Products with Thick and Large Section QT500-14", in actual production, the contents of carbon and silicon elements in molten iron after spheroidizing treatment need to be controlled respectively at C: 3.1-3.30%, Si: 3.30-3.60% can ensure the internal structure balance of thick and large section castings, and the mechanical properties of alloy materials cannot be stable to meet the requirements of EN1563:2012 standard
In the Chinese invention patent application CN108611551A "High silicon solid solution strengthened ferritic ductile iron castings and its manufacturing method", the content of carbon and silicon elements after spheroidizing treatment is controlled at C: 3.25-3.35%, Si: 3.70-3.80 %, the trace element Sb is added to the alloy composition, and the cupola furnace is used for melting, the melt processing process is long, the operation is cumbersome, and the matrix graphite structure is unstable
In the Chinese invention patent application CN103757517A "A production method of as-cast ferrite-based nodular cast iron QT500-14", among the mechanical properties tested, the elongation of the cast test block cannot be stabilized ≥ 14%
Although the high-silicon solid-solution strengthening process guarantees the complete ferrite matrix structure from the aspects of composition design and smelting process, the comprehensive mechanical properties of the ductile iron material that presents this matrix metallographic structure need to be further improved

Method used

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  • Preparing method for as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron
  • Preparing method for as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron
  • Preparing method for as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron

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Embodiment 1

[0036] The present invention provides a method for preparing a mixed matrix QT500-14 cast ductile iron, comprising the steps of:

[0037] Sl, raw material input mass percentage is as follows: iron: 60 ~ 80%, scrap: 5 to 20%, return scrap: 5 to 20% of electrolytic copper plate: 0.1 to 0.2%, of pure nickel plate: 0.3 to 0.4%. In particular, the use of pig iron Q10 ductile iron pig iron, comprising the following mass percent composition: C: 4.3 ~ 4.5%, Si: 0.8 ~ 0.9%, Mn <0.1%, P <0.04%, S <0.02%; the scrap quality carbon steel scrap, comprising the following mass percent composition: C: 0.1 ~ 0.15%, Si: 0.2 ~ 0.4%, Mn: 1 ~ 1.3%, P <0.03%, S <0.02%. Pig iron and steel scrap prior to use after blasting treatment required surface rust and other impurities.

[0038] S2, molten iron smelting: first package added in the molten scrap, pig iron and return scrap, to be added to the electrolytic copper sheet after scrap, pig iron and return scrap completely melted, the temperature control in ...

Embodiment 2

[0047] Example 2 relates to a method of preparing a mixed matrix QT500-14 ductile cast, this embodiment differs from embodiment 1 in that the embodiment: Example 2 mass% of Cu element in the embodiment of the control range of 0.05 to 0.1%. The present embodiment, after the end of the ball of the reaction, the sample is detected, the control ball after molten iron components: C: 3.5 ~ 3.8%, Si: 2.5 ~ 2.8%, Mn <0.3%, Cu: 0.05 ~ 0.1%, Ni: 0.3 ~ 0.4%, P <0.02%, S <0.02%, Mg: 0.04 ~ 0.07%, Re: 0.01 ~ 0.02%, the balance being Fe and unavoidable impurities.

[0048] Single cast test piece prepared above chemical analysis results shown in Table 1, cast metallographic examination of Table 2, binding figure 2 Understood that ball at Level 2, the size of the graphite balls 7 (viewed under 100 ×, graphite length> 1.5 ~ 3mm), spheroidization ratio ≥90% pearlite matrix 5 to 15% ferrite 75 to 90%. Preparation when the present embodiment is one kind of cast ductile iron mix matrix QT500-14 perfor...

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Abstract

The invention provides a preparing method for as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron. The preparing method includes the steps of raw material selecting and furnace burden matching, alloy component designing, smelting technology controlling, and melt treating and purifying of nucleating agents, spheroidizing agents, metal-stream inoculation agents, foamed ceramic filters and the like; and under the assistance of corresponding melt inoculation and spheroidizing treatment technologies, a good-performance as-cast-condition mixed matrix spheroidal graphite cast iron material is obtained. According to the as-cast-condition mixed matrix QT500-14 spheroidal graphite cast iron material, the content range of pearlite in a matrix structure is 5%-20%, the content range of ferrite in the matrix structure is 75%-90%, the spheroidizing grade is 2, the size of graphite nodules ranges from 6 grades to 7 grades, and the spheroidizing rate of the graphite nodules is largerthan or equal to 90%. The mechanical property of a separated test bar of casting reaches Rm>=500 MPa, Rp0.2>=380 MPa, and A>=14%. Combined with a furan self-hardened resin sand casting technology, thepreparing method can meet the requirement for large spheroidal graphite cast iron part production and technology development, spheroidal graphite cast iron parts high in strength and high in ductility are produced, and the requirements for prolonging the fatigue service life and achieving light design of high-grade parts are met.

Description

Technical field [0001] The present invention relates to the field of high performance metallic material, in particular preparation method of mixing a matrix QT500-14 relates to a cast ductile iron. Background technique [0002] In recent years, we can see the development trend of energy from chemical, automotive lightweight, high-end machine tools, rail transportation and other industries, equipment and technology and device structure gradually to complex, high-precision in the direction of development, which is no doubt the mechanical properties of the material presented higher requirements, particularly requirements for performance and high-end equipment used in large strength ductile iron materials, elongation higher and higher, and therefore need to continue to improve the strength and toughness of ductile materials such as overall performance, meet market demand . QT500-7 traditional technology and QT600-3 ductile iron casting, the matrix structure which contains 30% -60% pe...

Claims

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Application Information

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IPC IPC(8): C22C37/04C22C37/10C22C33/10
CPCC22C33/10C22C37/04C22C37/10
Inventor 李艳磊张辉赵龙耿鹏鹏褚玮李瑞吴国
Owner SHANGHAI TOBACCO MACHINERY
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