Smelting method of axle steel for high-speed motor car

Abstract

The invention relates to a smelting method of axle steel for a high-speed motor car, which comprises the following steps of: I. smelting in an electric furnace, firstly adding steel scraps into the electric furnace and adding pretreated molten iron, wherein the weight proportion of the pretreated molten iron is 80% to 95%, and in the steel scraps, P is less than or equal to 0.015% and S is less than or equal to 0.010%; blowing oxygen and adding lime, and tapping from the electric furnace after P is less than or equal to 0.008%; adding slagging materials, iron alloys and metals into steel ladles according to the types of steel; II. adopting slag systems with high alkalinity and high Al2O3 content for ladle furnace refining, controlling the alkalinity R of molten slag, wherein R is equal to 4.0 to 6.0; the molten steel comprises following components in percent by weight: 0.26 to 0.31% of C, 0.20 to 0.35% of Si, 0.55 to 0.70% of Mn, less than or equal to 0.005% of S, less than or equal to 0.015% of P, 0.75 to 0.90% of Cr, 2.90 to 3.30% of Ni, 0.45 to 0.55% of Mo and 0.08 to 0.13% of V; and III. feeding Si and Ca into the molten steel and blowing argon from the bottom after carrying out VD (Vacuum Distillation) and the vacuum refining. Inclusions of the steel rolled axle smelted by the smelting method of axle steel for the high-speed motor car meet the using requirements on the high-speed axle.

Description

Technical field [0001] The invention relates to a method for smelting axle steel for high-speed trains, in particular to a method for smelting 30NiCrMoV12 steel for axles of high-speed trains. Background technique [0002] Axle is an important running component of railway train, and its quality directly affects the safety of railway operation. At present, all high-speed EMU axles in my country are imported, which is still blank in China. The failure mode of the axle is mainly fatigue fracture, which is a process in which cracks occur and propagate to cause fracture. The harm of non-metallic inclusions is mainly to promote the generation of fatigue cracks, and under certain conditions, accelerate the crack propagation, thereby accelerating the fatigue failure, and the location of the inclusions is often the source of fatigue cracks. Therefore, axle steel has very strict requirements for inclusion levels, especially for high-speed EMU axles with a speed of more than 200 kilometer...

AI Technical Summary

Problems solved by technology

Dissect the imported 30NiCrMoV12 steel axle, and the inclusions of A, B, C, and D in the steel are not more than 0.5 grades. Foreign steel companies keep the smelting technology of 30NiCrMoV12 steel secret to the outside world. The known smelting technology is like the domestic conventional smelting method For the produced axle steel, it is difficult to control the inclusions of Type A, Type B, Type C, and Type D to be less than Level 1, and the level of inclusion control cannot meet the requirements for high-speed axles

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