两相区退火温度对TRIP钢组织性能的影响

Effect of intercritical annealing temperature on microstructure and properties of TRIP steel

针对600 MPa级别TRIP钢,进行了760、780、800、820、840、860℃两相区退火温度试验,利用扫描电镜和拉伸试验机等设备,分析了其对应的组织比例和力学性能检验结果,得出结论：随着两相区退火温度的升高,铁素体体积分数逐渐减少,钢板的抗拉强度值不断增加,但伸长率值却先下降再升高,在820℃伸长率有最大值,这与820℃时较高残余奥氏体体积分数和最大残奥中碳质量分数相对应,说明TRIP效应可以改善钢板的塑性指标,获得最佳强塑组合;在800~820℃的两相区转变温度范围内,强塑积可以达到2.17×104MPa·%,为600 MPa级TRIP钢退火工艺提供了实际指导。

Aiming at 600 MPa TRIP steel, the experiments of intercritical annealing at 760, 780, 800, 820, 840, 860 ℃, respectively, were carried out. By means of scanning electron microscopy and tensile test, the phase proportion and the mechanical property were measured and analyzed. It was found that with the increase of intercritical annealing temperature, the ferrite content gradually reduced, the tensile strength gradually increased, while the tensile elongation first decreased and then increased with a maximum value at 820 ℃. This maximum elongation was attributed to the best combination of austenitic volume fraction and carbon content, indicating that the TRIP effect can improve the plasticity and thus results in a best combination of strength and plasticity. In the annealing temperature range at 800-820 ℃, a maximum value of the product of strength to ductility about 2.17 × 10^4 MPa .% was obtained, which was useful to the design of annealing process of the 600 MPa TRIP steel.