Abstract: Based on the hot ductility curves at 600～1400 ℃ tested by Cleeble1500 thermal/strain simulation machine for 0.16~0.20C,0.020~0.060Al_t,Q235B steel 70 mm x 1500 mm thin slab produced by compact strip production (CSP)process,the third brittle zone of cast slab was between 700~900 ℃.Therefore the crack of cast slab easily forms as straightening in this temperature range. With fracture morphology analysis by scanning electron microscope and composition analysis by electron probe micro analyzer, it is obtained that the deformation-induced ferrite network precipitation and AlN precipitated at lower temperature austenitic range lead to cast slab embritlement.

Key words: CSP Process, Q235B Steel, Thin Slab, Hot Ductility, Crack

摘要： 根据Gleeble1500热/应变模拟试验机测试的CSP薄板坯连铸工艺生产的成分(%)为0.16~0.20C,0.020~0.060Al_t Q235B钢的70 mm ×1 500 mm薄板坯600~1400℃热塑性曲线,得出连铸坯第Ⅲ脆性区为700~900℃,如在此温度范围矫直,铸坯易产生裂纹。通过扫描电镜分析断口形貌和电子探针的成分分析,得出形变诱导铁素体呈网状析出和奥氏体在低温区域析出氮化物(AlN)导致铸坯脆化。

关键词: CSP工艺, Q235B钢, 薄板坯, 高温塑性, 裂纹