600MPa热镀锌双相钢退火温度及成分优化

Annealing Temperature and Composition Optimization of Hot Dip Galvanizing 600 MPa Dual Phase Steel

在工业试生产600 MPa热镀锌双相钢时,分析不同退火温度（800、820、840℃）对成品组织性能的影响,并对退火温度和成分进行优化。结果表明：成品主要组织均为铁素体＋马氏体（面积分数8%-12%）,退火温度升高马氏体含量下降,晶粒尺寸逐渐增大,840℃退火出现少量珠光体。成品力学性能符合标准要求,强度偏高,随温度升高屈服、抗拉强度下降,伸长率、屈强比变化不明显。对成分C,Mn元素微调,采用800-810℃退火,成功稳定批量生产600 MPa级双相钢,性能均值为：屈服强度360 MPa、抗拉强度630 MPa、伸长率26%、屈强比0.57。

When the hot dip galvanizing 600 MPa dual phase steel were industrial trial production, the effect of the micro- structure and mechanical properties with different annealing temperatures （800,820,840 ℃ ） had been analyzed, and then annealing temperature and composition had been optimized. The results show that the main microstructure is comprised of ferrite and martensite, the area fraction of martensite is 8%-12%, the content of martensite decreases and the grain size increases as the annealing temperature increasing. When the annealing temperature is 840 ℃, there is a little pearlite. The mechanical properties can meet the performance requirements, but the strength is high. The yield strength and tensile strength decrease as the annealing temperature increasing, elongation and yield strength ratio had little influence. Hot dip galvanizing 600 MPa dual phase steel has been successfully and stably produced in bulk with fine-tuned compositions and annealing temperature of 800-810 ℃. The performance of mean is： yield strength 360 MPa, tension strength 630 MPa, elongation 26%, yield strength ratio 0.57.