含钛高强钢板坯的火焰切割裂纹

钛高强钢具有成本优势，得到了广泛的应用，但添加钛易诱发板坯裂纹缺陷。针对wTi=0.1%的高强钢板坯火焰切割裂纹问题，采用ANSYS模拟了板坯火焰切割的过程及随后的温度变化，用光学显微镜分析了板坯裂纹形貌及组织、用热膨胀仪测定了wTi=0.1%的高强钢的温度-膨胀曲线，从板坯火焰切割后相变的角度探讨了裂纹形成原因。结果表明, wTi=0.1%的高强钢板坯火焰切割后，距切割面30mm以内冷却速度可达10℃/s以上，冷却速度快使板坯产生贝氏体和马氏体相变，导致了板坯火焰切割裂纹的产生。

Torch cutting crack of Ti bearing high strength slab

Ti alloyed high strength steel had gained wide spread application because micro- alloying element Ti was cheaper compared with other micro- alloying elements. But addition of Ti was prone to cause crack defect on slab. Aiming at the torch cutting crack on high strength slab bearing wTi=0.1%, the temperature variation during and after torch cutting was simulated by ANSYS software, the morphology of crack and microstructure of slab were examined and the temperature- dilatation curve of the steel was tested, which elucidated the the reasons for the crack from the perspective of phase transformation during and after torch cutting. The results showed that cooling rate of the high strength slab bearing wTi=0.1% could reach as high as 10℃/s within the range of 30mm from torch cutting plane after torch cutting. High cooling rate made the Beinatic and Martensitic phase transformation, which caused the torch cutting cracks on the slab.