低碳贝氏体型厚规格X70管线钢低温韧性研究

Study on Low Temperature Toughness of Low Carbon Bainitic X70 Pipeline Steel with Heavy Wall Thickness

以洁净钢冶炼控制技术、特厚板坯及优化的TMCP工艺为基础,通过对3种不同的成分体系进行对比,研究了不同成分体系对25 mm厚X70管线钢低温韧性的影响,确定了以低CMo-Ni复合成分生产贝氏体型厚规格管线钢的思路。以此为指导,进行了Φ1 219 mm×30.2 mm规格X70管线钢管工业化生产,制管后强韧性能较钢板小幅上升,焊缝及热影响区组织接近母材,具有良好的焊接性能。

Based on the clean steel-making technology, extremely thick slabs and optimized TMCP process, through comparison of three different chemical composition system, the effect of different composition on the low temperature toughness for 25mm X70 pipeline steel was studied, and the thought utilizing low C-Mo-Ni composite composition to produce bainitic pipeline steel with heavy wall thickness was determined. Based on this situation, the industrial production of X70 line pipe with size ofφ1 219 mm＆#215;30.2 mm was conducted. After the plates were made into pipes, the strength and toughness of pipe increase slightly, the microstructure of weld and base metal is similar to base metal, and it is with good weldability.