中文摘要：

研究了轮箍钢低倍组织和连铸温度对白点敏感性、断裂韧性的影响．结果表明，连铸温度对白点敏感性有影响，低温铸坯（尾坯）的白点敏感性略高于高温铸坯（头坯）．低倍组织对白点敏感性影响显著，柱状晶区的白点敏感性最低，等轴晶区的白点敏感性最高．但是，低倍组织和连铸温度对氢扩散和条件断裂韧性KIQ均没有影响．

英文摘要：

The effects of the macrostructure of tyre steel and continuous-casting temperature on hydrogen flaking and fracture toughness, KIQ, have been investigated. The results show that the continuous-casting temperature can influence the susceptibility to hydrogen flaking, for example, the susceptibility of the low temperature billet （end billet） is higher than that of the high temperature billet （head billet）. In addition, there is an evident effect of macrostructure on the susceptibility to hydrogen flaking, which is the highest in the columnar grain zone and the lowest in the equiaxed grain zone. However, the hydrogen diffusivity, Da, and fracture toughness, KIQ, are almost independent upon the macrostructure of tyre steel and also continuous-casting temperature.