超高强度冷轧双相钢组织与性能

在Gleeble-3500热模拟试验机上进行冷轧超高强度双相钢的连续退火工艺研究,利用光学显微镜、扫描电镜、透射电镜和拉伸试验研究了连续退火过程中各个参数对1000MPa级冷轧双相钢组织性能的影响.结果表明:试验用钢在退火温度800℃下保温80s,可以得到抗拉强度为1030MPa、延伸率为14%超高强双相钢;随着退火温度的升高,屈服强度和抗拉强度降低.当退火温度为830℃时,显微组织中粒状的非马氏体组织明显增多.过时效温度低于300℃时,屈服强度和抗拉强度变化不大;当过时效温度超过300℃时,抗拉强度急剧下降,屈服强度先降低后升高,在过时效温度为360℃时开始出现屈服平台.

Microstructure and properties of ultra-high strength cold-rolled dual phase steel

The continuous annealing process of ultra-high strength cold-rolled dual phase steels was simulated using a Gleeble-3500 thermal simulator. The effects of continuous annealing parameters on the microstructure and mechanical properties of the 1 000 MPa grade dual phase steel were investigated by optical microscope, scanning electron microscope, transmission electron microscope and tensile tests. It is shown that a dual phase (DP) steel with a tensile strength of 1 030 MPa and a total elongation of 14% was obtained after being soaked at 800 qC for 60 s. With the increase of annealing temperature, the yield strength and tensile strength decrease. When the annealing temperature reaches 830℃, the volume fraction of granular non-martensite in the microstructure increases obviously. When the over-aging temperature is lower than 300℃, the yield strength and the tensile strength change slightly. When the over-aging tempe'rature is higher than 300℃, the tensile strength decreases strongly, whereas the yield strength reduces first and then increases. There is yield point elongation when the over-aging temperature is 360℃.