结晶器振动对连铸坯初始裂纹形成影响

摘要 简要分析了振动结晶器内弯月面坯壳受力研究现状，归纳了坯壳初始裂纹的形成原因.在此基础上提出描述伴随结晶器振动的弯月面坯壳受力模型，阐述振动周期内初凝坯壳力学状态.分析表明，振动特定时段内，结晶器振动引起施加于弯月面处初凝坯壳上的机械应力为148.4kPa，而该温度下坯壳高温临界断裂强度仅为119.1kPa，结晶器振动产生的机械应力超过临界断裂强度时极易引发初始裂纹的形成.当结晶器振动速度大于1.61m·min-1时弯月面处坯壳初始裂纹开始形成，且产生于钢水自由液面以下2.15~5.4mm位置范围.
Abstract：The previous researches on the stress state of initial solidifying shell in oscillation mold and the detailed reasons to clarify the crack formation process were summarized. The mechanical stress caused by mold oscillation has a dominant contribution to the initial cracks formation as a nonnegligible factor， so a new model was proposed to shed light on the influence of mold oscillation on the initial cracks formation. The stress states of the shell were analyzed for an oscillation cycle. The results showed that the mold oscillation plays an important role on the cracks formation because the maximum bending stress in initial solidifying shell can reach to 148.4kPa and the critical fracture strength of the shell is only 119.1kPa. The initial crack will form when the oscillation velocity is higher than 1.61m·min-1， which is located in the region of 2.15~5.4mm under the free surface of steel in the mold because the critical fracture strength at a certain temperature is exceeded.