High strength and high toughness heavy haul train wheel steel and heat treatment method thereof

Abstract

Belonging to the technical field of steel for railway wheels, the invention relates to a high strength and high toughness heavy haul train wheel steel and a heat treatment method thereof. The steel comprises the following chemical components by weight percentage (wt.%): 0.75-0.85wt.% of C, 0.80-1.00wt.% of Si, 0.40-0.80wt.% of Cr, 0.30-0.50wt.% of Mn, 0.01-0.03wt.% of Nb, 0.02-0.06wt.% of V, 0.010-0.025wt.% of Al, less than 0.015wt.% of P, less than 0.015wt.% of S, and the balance Fe and unavoidable impurities. After conventional smelting, casting and forging, a wheel is subjected to a novel heat treatment process adopting tread quenching and sub-sectional cooling. After heat treatment, the structure at a standard tensile test position of a rim is a fully lamellar perlite structure, the size of a pearlite colony is 2-6microm, and the pearlite interlamellar spacing is 0.05-0.09microm. The room temperature tensile strength of the rim is 1200MPa grade, the percentage elongation after fracture is greater than 12%, and the web 20DEG C impact energy KU2 is greater than 20J. Therefore, the high strength and high toughness heavy haul train wheel steel has excellent strength and toughness matching, and can be used for heavy haul trains.

Description

technical field [0001] The invention belongs to the technical field of steel for railway wheels, and relates to a steel for heavy-duty train wheels with high strength and high toughness and a heat treatment method thereof. Background technique [0002] Wheels are an important product variety of steel for railways and rail transit vehicles. In recent years, China's rail transit industry has developed rapidly. Problems are becoming more and more serious, such as wheel peeling and wear, etc., which have highlighted that the current wheel varieties cannot meet the needs of the current railway development. Heavy-haul railways symbolize the level of freight transport in a country. A breakthrough in heavy-haul railway technology not only improves logistics efficiency, but more importantly, increases cargo transportation capacity. At present, the technical conditions of freight car wheels used in China's railway industry include TB / T 2817-1997 "Technical Conditions for Rolled Steel...

AI Technical Summary

Problems solved by technology

These patents use a single microalloying, and do not pay attention to the influence of the matching of Nb and V composite microalloys on the strength and toughness; while the US patent US7559999B2 (Railroad wheels steels having improved resistance to rolling contact fatigue) provides a high carbon wheel steel, Nb, V compound microalloying (Nb: 0.01-0.12wt.%, V: 0.10-0.30wt.%) design is adopted to improve the contact fatigue performance of the wheel

However, the disadvantage of this patent is that the design of the V content is relatively high, and VC is more precipitated at high temperature, which is not conducive to refining the austenite grains, ensuring the C content of the pearlite structure of the wheel steel and the strength of the wheel steel

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