论文部分内容阅读
利用Gleeble-1500热模拟机进行热拉伸实验,研究了变形温度800~1200℃和应变速率0.002~20 s-1范围内23CrNi3Mo钢热塑性行为及断裂机理。结果表明:23CrNi3Mo钢具有优异的高温塑性。不同的变形温度下,峰值应力随温度线性降低,而随应变速率的增加峰值应力升高。应变速率2 s-1时,热拉伸过程中,高温断裂机制为韧性断裂,断口呈韧窝形貌。随着温度的升高,韧窝直径变小而深度增加。变形温度1050℃时,随应变速率的降低,断裂机制由韧性断裂转变为脆性断裂。应变速率高于0.2 s-1时,断口呈韧窝形貌;而应变速率低于0.2 s-1时,断口呈沿晶断裂形貌。高温拉伸断裂过程中,夹杂物的存在对裂纹的萌生与扩展有一定的影响作用。
The hot tensile test was carried out on a Gleeble-1500 thermal simulator to study the thermoplastic behavior and fracture mechanism of 23CrNi3Mo steel at a strain rate of 800-1200 ℃ and a strain rate of 0.002-20 s-1. The results show that: 23CrNi3Mo steel has excellent high temperature plasticity. At different deformation temperatures, the peak stress decreases linearly with temperature, whereas the peak stress increases with increasing strain rate. When the strain rate is 2 s-1, the high-temperature fracture mechanism is ductile fracture and the fracture is ductile in the hot drawing process. As the temperature increases, dimples become smaller in diameter and deeper in depth. When the deformation temperature is 1050 ℃, the fracture mechanism changes from ductile fracture to brittle fracture with the decrease of strain rate. When the strain rate is higher than 0.2 s-1, the fracture is ductile; while the strain rate is lower than 0.2 s-1, the fracture is along the intergranular fracture morphology. In the process of tensile fracture at high temperature, the existence of inclusions has a certain influence on the initiation and propagation of cracks.