大口径厚规格X80管线用钢板热轧工艺研究

Study on Hot Rolling Process of Steel Plate for X80 Grade Pipeline with Large Diameter and Thick Wall Specification

在X80管线钢热轧板材合金化成分体系设计的基础上,利用中试冶炼轧制平台开展X80管线钢板热轧工艺研究。结果表明:X80管线钢板压下率大于26%并待温60 s时,奥氏体晶粒发生再结晶,获得明显细化的再结晶组织;卷取温度为400℃时,M-A岛细而弥散地分布于基体中,与之相对应的DWTT韧性较优。综合考虑X80管线钢化学成分的合金化特点,以及板卷屈服强度、屈强比、夏比冲击功和DWTT剪切面积百分比的理想控制水平,为工业化试制选择了(400±35)℃的卷取温度。

Based on the design of alloying composition system of hot rolled X80 grade pipeline steel plate,the paper studies the hot rolling process of the X80 grade pipeline steel plate by means of the melting and rolling platform of the pilot plant.The results show that when the reduction ratio is over 26%and the holding time equals to 60 s for the X80 grade pipeline steel plate,the austenite grains recrystallization is initiated and apparent refined and recrystallized microstructure is obtained;when the coiling temperature is 400℃,the refined martensite and austenite islands are dispersed in the matrix with excellent corresponding DWTT toughness.With a comprehensive consideration on the alloying characteristics of the chemical composition for X80 grade pipeline steel,the ideal control level of the yield strength,yield to tensile strength ratio,Charpy impact energy value and percentage of DWTT shearing area for the plate coil,the coiling temperature of(400±35)℃is selected for the industrial trial production.