Bainite steel wheel for rail traffic heavy-duty freight car and manufacturing method thereof

Abstract

The invention discloses a Bainite steel wheel for rail traffic heavy-duty freight car and a manufacturing method thereof. The Bainite steel wheel comprises the chemical components of 0.10-0.40% of C,0.40-2.10% of Ni, 0.25-1.50% of Cr, 0.70-2.10% of Mn, 0.20-1.00% of Si, 0.01-1.00% of W, 0.05-0.60% of Mo, 0.01-0.80% of Cu, 0.01-0.20% of V, 0.001-0.20% of Nb, 0.0001-0.0350% of B, 0.001-0.040% of RE, less than or equal to 0.020% of P, less than or equal to 0.020% of S, and the balance Fe and inevitable residual elements, specifically, the sum of Mn and Cr is larger than or equal to 2.0% and smaller than or equal to 3.0%. By adoption of a novel alloy design system and alloying principle of C-Ni-Mn-Cr-Mo, after the wheel is formed, a rim is of a carbide-free Bainite tissue structure after advanced thermal treatment, and the wheel has excellent comprehensive mechanical properties, corrosion resistance and service performance, and particularly has the characteristics of high strength, hardness and toughness, high wheel track rolling contact fatigue (RCF) performance and hot crack resistance, and the like.

Description

technical field [0001] The invention belongs to the technical field of rail transit, and relates to a bainite steel wheel for rail transit heavy-duty trucks and a manufacturing method thereof, in particular to a heavy-duty truck with an axle load of 30 to 45 tons and a running speed of ≤160km / h. Carbide-free bainitic steel wheels for trucks and methods of manufacturing the same. Background technique [0002] "High speed, heavy load and low noise" is the main development direction of rail transit in the world. Wheels are the "shoes" of rail transit and one of the most important walking parts, which directly affects the safety of operation. During the normal operation of the train, the wheel bears the full load of the vehicle and is damaged by wear and rolling contact fatigue (RCF). It has a very complex relationship and is in a dynamic and alternating stress state, especially the wheels and rails, wheels and brake shoes (except for disc brakes) are two pairs of friction pair...

AI Technical Summary

Problems solved by technology

[0011] (1) The yield strength of the wheel rim is low, generally around 700MPa. Because the rolling contact stress between the wheel and the rail is large during the operation of the wheel, sometimes exceeding the yield strength of the wheel steel, the wheel is plastically deformed during operation, resulting in the subsurface of the tread Plastic deformation occurs, and because there are brittle phases such as inclusions and cementite in the steel, it is easy to cause micro-cracks on the rim, and these micro-cracks will produce defects such as peeling and rim cracking under the action of rolling contact fatigue of the wheel.

[0012] (2) The carbon content in the steel is high and the thermal damage resistance is poor

[0013] (3) Poor hardenability of wheel steel

There is a certain hardness gradient in the rim of the wheel, and the hardness is uneven, which is prone to defects such as rim wear and out-of-roundness

[0014] (4) It does not contain corrosion-resistant alloy elements, the oxide scale on the surface of the wheel has poor ability to resist damp heat and corrosive environments, and the chemical electrode potential difference between ferrite and cementite is large, which is easy to generate corrosion micro-batteries, resulting in the overall corrosion resistance of the wheel Difference

[0015] (5) Under low temperature conditions, the toughness of the wheel drops significantly. Once a crack source is generated, it will expand rapidly and eventually form a crack and break

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