铸坯差温预压下处理工艺研究

由于对高性能钢的需求越来越广,进而对其连铸坯的质量要求不断提高,而铸坯中又以疏松缺陷最难消除。因此,对表面950℃、中心1 300℃以上的差温条件下的铸锭进行预压下试验,在铸锭大变形量部分,由于芯部处于高温奥氏体脆性区,塑性较差从而出现热裂;而小变形量部分,在差温作用下,铸锭内部优先变形,疏松和微观空洞被明显压合,又由于一定范围内的再结晶,减轻了铸锭内部的晶界偏析。试验结果表明,小变形量的差温预压下技术可以显著提高铸坯质量,具有进一步研究和在连铸坯生产中应用的重要价值。

Investigation of deformation pretreatment with temperature gradient of casting billet

The quality requirements for continuous casting billet have been increased with the development of high performance steel,but it is difficult to eliminate the shrinkage defect.The deformation pretreatment of casting billet was investigated with the temperature gradient of 950 ℃ in the surface and 1 300 ℃in the core.The results show that the center of casting billet appear the thermal crack due to brittleness of high temperature austenite under the condition of large reduction.However,under the condition of small deformation,the shrinkage and the micro- pore are closed and the degree of segregation decreased owing to the priority deformation and the re- crystallization in the center.That means the small deformation pretreatment with temperature gradient for continuous casting billet is wealth to be further researched and practiced in production.