针对欧洲高速动车使用的DB920车轮进行了工艺实验和实验室实验。结果表明，DB920车轮轮辋部位组织主要为少量铁素体和细珠光体，当组织中的铁素体比例较高且呈网状分布时，在进行断裂韧性评价实验时易出现撕裂状断口，在撕裂带侧面有大量韧窝，断裂韧性值（KQ）较高；相反，当铁素体比例较低时，断面相对平整，断裂方式以沿晶断裂和解理断裂为主，断裂韧性较差。组织分析和有限元模拟分析结果表明：喷水冷却时，轮辋处的冷却速度自踏面向内不断降低，冷速越慢，相变后生成铁素体比例就越高，断裂韧性也就越好。结合连续冷却实验的结果估算，对此成分车轮钢而言，当冷速大于1℃／s时，相变后不能获得足够的铁素体以保证此区域的断裂韧性。
European high speed railway wheels DB920 were employed to investigate the processing-microstructure-property relations of the wheel steel by experiments and simulation. Effect of microstructure of the wheel steel on fracture toughness of high-speed railway wheel was examined. The results show that the mierostrueture of rim consists of small amount of ferrite and fine pearlite. As the proportion of ferrite increases, it is prone to tearing fracture with a large number of dimples for fracture toughness tests and the fracture toughness can be improved. On the other hand, with the proportion of ferrite reduction, smooth fracture of the sample was observed with lower fracture toughness by cleavage crack and intergranular fracture. Based on the microstrueture observation and finite element analysis, it suggested that the cooling rate of rim decreased from tread to center and the proportion of ferrite increased. For this railway wheel steel, the cooling rate should be controlled at 1 ℃/s to guarantee the toughness of railway wheels.
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