Alloy forged steel and production method and application thereof

Abstract

The invention relates to alloy forged steel and a production method thereof. The production method comprises the following steps: alloy smelting, wherein the alloy comprises the following components by weight percent: 0.24 percent to 0.31 percent of carbon, 0.20 percent to 0.50 percent of silicon, 0.50 percent to 0.90 percent of manganese, 1.10 percent to 1.50 percent of chromium, 0.50 percent to 0.89 percent of molybdenum, 0.20 percent to 0.40 percent of vanadium, less than or equal to 0.015 percent of phosphorus, less than or equal to 0.012 percent of sulfur, the balance of iron and unavoidable impurities; pouring a steel ingot; diffusion annealing, warming the steel ingot, heat preservation, furnace cooling, and then drawing a charge and wind cooling; forging blank; annealing after forging, warming the blank, heat preservation, furnace cooling, and then drawing a charge and wind cooling; heat treatment, quenching and then tempering. The production method of the alloy forged steel is relatively simple, can produce the alloy forged steel with fine comprehensive mechanical property and higher coefficient of thermal conductivity in the ordinary temperature state and the high temperature state.

Description

technical field [0001] The invention relates to a forged steel and a production process of the forged steel, in particular to a chemical composition and a heat treatment method of an alloy forged steel used for a brake disc of a high-speed train. Background technique [0002] The brake disc is an important part of the EMU braking system, especially for 250Km / h and higher-speed EMUs. The quality and performance of the brake disc directly affect the various performance indicators of the EMU, and the impact on the quality and performance of the brake disc The biggest is the various mechanical performance indicators of the alloy forged steel material used for the brake disc. Since the brake disc will generate a large amount of frictional heat during the braking process, the temperature of the disc body will rise (the surface temperature of the friction disc can reach above 500°C), and the brake disc is subjected to alternating thermal stress during operation. The material of th...

AI Technical Summary

Problems solved by technology

For example, Chinese patent document CN1385628 discloses a material for high-speed train brake discs. In order to meet the performance requirements of high-speed train brake disc materials, alloy components such as chromium, nickel, molybdenum, and vanadium are added. While increasing the strength of the material, it brings about a significant decrease in the plasticity and toughness of the material; although the addition of nickel can improve the low-temperature plasticity and toughness of the material to a certain extent, the addition of nickel will form retained austenite, which has a negative impact on the material's high temperature. Creep resistance (long-term stress at high temperature, deformation, called creep) performance not only does not promote, but has a negative impact on the high temperature performance of the material

For another example, the alloy forged steel with the material grade of 25Cr2Mo1VA has a tensile strength of 837MPa and a yield strength of 782MPa at 500°C. The margin of tensile strength is insufficient (the technical requirement for train brake discs is ≥800MPa), and the yield strength is slightly lower. Safety performance is difficult to guarantee

[0004] (2) The thermal conductivity of the existing alloy forged steel is low

[0005] (3) The heat treatment method of quenching and tempering for the existing alloy forged steel is unreasonable, and the performance of the material cannot be fully further optimized and improved; the resulting brake disc is prone to deformation and cracks, which affects braking Disk life

[0006] Therefore, the alloy forged steel used for forged steel brake discs of high-speed trains in my country mainly relies on imports and is expensive. In order to meet the needs of the development of high-speed railways in my country, a high-speed train with excellent comprehensive mechanical properties, easy manufacturing, and high cost performance should be developed. Materials for brake discs are particularly urgent

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