1000MPa级TRIP钢的组织性能及强化机理

鉴于热镀锌TRIP钢在成分和工艺上的特殊性,试验采用低Si含P以及V微合金化的成分设计思路,并进行镀锌连续退火工艺模拟,分析其微观组织和性能。探讨了残余奥氏体稳定性的影响因素及强化机理。结果表明,添加P和采取较高的冷轧变形量均有利于提高残余奥氏体量及其稳定性。在残余奥氏体的形变诱导马氏体相变、贝氏体和V析出的强化作用以及铁素体晶粒细化的共同作用下,抗拉强度和强塑积分别达到1 035 MPa和25 875 MPa·%。

Microstructure,Mechanical Properties and Strengthening Mechanism of 1000 MPa Grade TRIP Steel

In view of the specialties of hot-dip galvanized TRIP steel in composition and process, the designing idea for composition of low silicon and phosphorus-containing, vanadium micro-alloying was used in this experiment, and the process of hot-dip galvanization after continuous annealing was simulated. The microstructure and mechanical properties were analyzed, and the factors influencing the stabilization of retained austenite and the strengthening mechanism were investigated. The results showed that adding phosphorus and using a higher cold rolling reduction are all beneficial to improving the volume fraction and the stabilization of retained austenite. Under the joint action of the deformation induced martensite transformation of retained austenite, the strengthening effect of bainite and vanadium precipitation, and the refinement of ferrite grains, the product of tensile strength and strength-elongation reach to 1 035 MPa and 25 875 MPa·%respectively.