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利用Gleeble3500热模拟试验机对双相钢连铸坯的高温力学性能进行了研究,并通过Thermo-Calc热力学计算、差示扫描量热法(DSC)以及断口形貌与组织观察的方法,分析了其脆性区间产生的原因。研究表明,实验用钢的零强度温度(ZST)和零塑性温度(ZDT)分别为1450和1440℃,凝固前沿脆化温度区间较小,具有较好的抗高温裂纹特性。高温脆性区为1415~1440℃,其脆化的原因是晶界熔化,导致实验钢在应力作用下沿晶界开裂;低温脆性区为690~870℃,其脆化的原因是α-铁素体沿奥氏体晶界析出,导致实验钢在应力作用下沿晶界断裂。
The high-temperature mechanical properties of dual-phase steel billet were studied by Gleeble3500 thermal simulation test machine. The effects of heat treatment on the mechanical properties of dual-phase steel billets were analyzed by Thermo-Calc thermodynamics, differential scanning calorimetry (DSC) and fracture morphology and microstructure observation The reason for its brittle interval. The results show that the zero strength temperature (ZST) and zero plastic temperature (ZDT) of the experimental steel are 1450 and 1440 ℃, respectively, and the frontier embrittlement temperature range is smaller, which has better characteristics of high temperature cracking resistance. The high temperature brittle zone is 1415-1440 ℃. The reason of its embrittlement is that the grain boundary melts, which leads to the cracking of the experimental steel along the grain boundary under the stress. The low temperature brittle zone is 690-870 ℃. The reason of its embrittlement is α-ferrite Body along austenite grain boundary precipitation, resulting in experimental steel along the grain boundary fracture under stress.