Nb、Ni元素对沉淀强化型高强钢高温塑性的影响

Effects of Nb and Ni on high temperature plasticity of precipitation strengthened high strength steel

在Gleeble-3800热模拟试验机上对添加不同合金元素的沉淀强化型高强钢进行高温拉伸试验,分析了断面收缩率和抗拉强度随温度的变化情况,利用扫描电镜观察断口形貌。结果表明：在850~1300℃范围内含Ni钢、不含Nb和Ni钢及含Nb钢均存在高塑性区到低塑性区间明显的温度转折区,转折温度点分别为1000、1050和1150℃;含Nb试验钢的抗拉强度最高;3种试验钢的断口以韧性断裂为主,韧窝形状及尺寸是影响试验钢性能的主要因素。

High temperature tensile tests were conducted to the precipitation strengthened high strength steel with different alloying elements on the Gleeble-3800 thermal simulation test machine. The change of tensile strength with temperature was analyzed, and the macro and micro fracture morphology of the samples were observed on SEM. The results show that at the range of 850-1300 ℃, the Ni contained steel, without Ni and Nb added steel and Nb contained steel are found high plasticity regions, and the turning points are 1000 ℃ , 1050 ℃ and 1150 ℃ respectively. The tensile strength of Nb contained steel is the highest. The fracture morphologies of the three tested steels are mainly ductile fracture, and the properties of the tested steels are mainly affected by the shape and size of the fracture.