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A kind of high-strength vermicular graphite cast iron and preparation method thereof

A vermicular graphite cast iron, high-strength technology, applied in the field of high-strength vermicular graphite cast iron and its preparation, can solve the problems of low creep rate, unstable creep rate, low mechanical properties, etc., and achieve high-temperature and high-temperature mechanical properties. Effect

Active Publication Date: 2020-01-07
DONGFENG COMML VEHICLE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the problems of low creep rate, unstable creep rate and low mechanical properties of existing vermicular graphite cast iron, and provide a kind of high creep rate, good mechanical properties at room temperature and high temperature, and simple process operation. Vermicular graphite cast iron and its preparation method

Method used

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Examples

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Effect test

preparation example Construction

[0025] The preparation method of described a kind of high-strength compacted graphite cast iron, comprises the steps:

[0026] (1) Raw material ratio: The raw materials are mixed according to the following weight percentages: 30%-40% of the returned material, 50%-60% of the pig iron, and 0%-20% of the scrap steel;

[0027] (2) Smelting: Pour the mixed raw materials into the melting furnace, smelt to a molten state, add recarburizer and ferroniobium, copper, ferrochrome and other alloys according to the chemical composition test results to adjust the chemical composition of molten iron;

[0028] (3) Vermative treatment: according to the content of S in the molten iron, accurately weigh 0.25%-0.45% of the amount of vermicular agent poured into the molten iron and put it into the bottom of the ladle, and then pour 0.35%-0.45% of the molten iron into the The inoculant and molten iron are poured into 0.4%-0.5% steel shot to cover and compact the creeping agent; when the temperature...

Embodiment 1

[0052] A kind of high-strength vermicular graphite cast iron, its chemical composition by weight percentage is:

[0053] C: 3.65%; Si: 1.95%; Mn: 0.58%; P: 0.036%; S: 0.012%; Cu: 0.58%; The balance is iron and unavoidable impurities.

[0054] A high-strength vermicular graphite cast iron has a vermicular rate of 80%, a tensile strength of 577MPa, a high temperature strength of 300°C of 533MPa, a high temperature strength of 500°C of 428MPa, and a hardness of 252HBW.

[0055] A preparation method of high-strength vermicular graphite cast iron, comprising the following steps:

[0056] (1) Raw material ratio: The raw materials are mixed according to the following weight percentages: 35% of recycled material, 57% of pig iron, and 8% of steel scrap. Scrap steel adopts ordinary carbon non-alloy steel;

[0057] (2) Smelting: Use a 6t intermediate frequency furnace for molten iron smelting, smelt the returned materials, pig iron and scrap steel to a molten state, and add low S, low...

Embodiment 2

[0061] A kind of high-strength vermicular graphite cast iron, its chemical composition by weight percentage is:

[0062] C: 3.75%; Si: 1.77%; Mn: 0.45%; P: 0.030%; S: 0.015%; Cu: 0.48; Cr: 0.16%; The amount is iron and unavoidable impurities.

[0063] A high-strength vermicular graphite cast iron has a vermicular rate of 85%, a tensile strength of 530MPa, a high temperature strength of 300°C of 492MPa, a high temperature strength of 500°C of 404MPa, and a hardness of 249HBW.

[0064] A preparation method of high-strength vermicular graphite cast iron, comprising the following steps:

[0065] (1) Raw material ratio: The raw materials are mixed according to the following weight percentages: 30% of the recycled material, 50% of the pig iron, and 20% of the scrap steel. The recycled material is made of ductile iron and vermicular iron. Carbon non-alloy steel;

[0066] (2) Smelting: Use a 6t intermediate frequency furnace for molten iron smelting, smelt the returned materials, p...

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Abstract

The invention discloses high-strength vermicular graphite cast iron. The high-strength vermicular graphite cast iron is composed of the following components of, in percentage by weight, 3.6%-4.0% of C, 1.7%-2.2% of Si, 0.4%-0.6% of Mn, less than or equal to 0.04% of P, less than or equal to 0.02% of S, 0.40%-0.60% of Cu, 0.1%-0.3% of Cr, 0.005%-0.025% of Mg, 0.005%-0.025% of Re, 0.05%-0.2% of Nb,and the balance iron and inevitable impurities. The preparation method is divided into 4 steps, namely, raw material proportioning, smelting, vermicularizing treatment and pouring. According to the method, the operation is simple, vermicular graphite cast iron material with high vermicularizing rate and good performance at normal temperature and high temperature is obtained, and the problem that the strength of the vermicular graphite cast iron with the high vermicularizing rate is low is solved.

Description

technical field [0001] The invention relates to a cast iron material and a manufacturing method thereof, in particular to a high-strength vermicular graphite cast iron and a manufacturing method thereof. Background technique [0002] The characteristics of modern engines, such as high power per liter, compact structure, complex casting shape, high thermal load and mechanical load, not only put forward higher requirements for its design technology, but also for the materials and manufacturing technology of key components such as engine block and cylinder head. The material not only has high mechanical properties, excellent shock absorption performance and thermal fatigue performance, but also requires high compactness, uniformity and reliability. Among them, vermicular graphite cast iron has the properties of both nodular cast iron and gray cast iron, and is very suitable for manufacturing cylinder blocks, cylinder heads, brake drums and other parts that require high strength...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C37/10C22C37/06C22C33/10
CPCC22C33/10C22C37/06C22C37/10
Inventor 袁福安康明金通涂欣达霍卯田王林晏克春
Owner DONGFENG COMML VEHICLE CO LTD