晶粒尺寸对车轮钢解理断裂韧性的影响

Effects of grain size on the cleavage fracture toughness of a wheel steel

摘要: 通过紧凑拉伸试验研究了碳的质量分数约为0.5%的C50车轮钢解理断裂韧性K_IC(即条件断裂韧性K_Q)与晶粒尺寸的关系.结果表明,晶粒尺寸对试样的断裂韧性有明显的影响,但决定车轮钢解理断裂韧性的是组织中最大的晶粒尺寸,而不是平均晶粒尺寸,最大晶粒尺寸越大,断裂韧性越低.对于C50车轮钢,当前5%的最大晶粒平均尺寸为30~73μm时,车轮钢的条件断裂韧性K_Q与晶粒平均尺寸的对数呈线性关系.

Abstract: The relationship between grain size and cleavage fracture toughness K_IC, i.e., conditional fracture toughness K_Q, was investigated for a high speed wheel steel with 0.5% C by compact tension testing. It is indicated that the grain size has an evident effect on the fracture toughness. The fracture toughness is more dependent on the largest grain size than the average grain size of the C50 wheel steel. When the average size of the 5% largest grains is in the range of 30 to 73 μm, the cleavage fracture toughness K_Q decreases linearly with the logarithm of average size of these largest grains increasing.