700MPa管线钢热压缩变形及组织研究

利用Gleeble-3500型热模拟机,研究700 MPa管线钢(/％:0.07C,0.90Si,0.60Mn,0.008P,0.002S,0.30Ni,0.10Cr,0.12Mo,0.06V,0.03Nb,0.28Cu,0.04Alt,0.006 0N) 20 mm热轧板在850～1 250℃和应变速率0.01 ～1 s-1下单道次热压缩变形及组织演变,得出单道次压缩变形真应力-真应变曲线,热压缩再结晶动态图和动态再结晶开始时间与变形温度关系(RTT)曲线.研究结果表明,发生再结晶由变形温度和应变速率共同决定,该700 MPa管线钢在温度1 100 ～1 250℃和应变速率0.01 ～0.1 s-1下压缩变形时容易发生再结晶.再结晶发生机制是热压缩应变,使得原始晶粒破碎、新晶界产生迁移促使新晶核生成.