EFFECT OF HOT-BENDING PROCESS ON MICROSTRUCTURE AND MECHANICAL PROPERTY OF K65 SUBMERGED ARC WELDED PIPE

摘要：

　　Hot-bended pipes are essential parts in the construction of long distance pipeline.They are usually made from longitudinally submerged arc welding(LSAW)pipes subjected to hot bending process including quenching and tempering process,which often deteriorates the impact property of the welded pipe.A hot-bended LSAW pipe with a wall thickness of 30.8 mm was fabricated by double-sided four wires submerged arc welding with solid wire and fused flux.Microstructural and property of both as-weld and as-bended pipe were examined.The pipes in two states show a similar tensile strength of 665-670 MPa,and fail in the heat affected zone during the tensile test.The weld metal of as-welded pipe consists of acicular ferrite and small fraction bainite and M-A constituents,while mixture of polygonal ferrite,degenerate perlite and precipitated carbides of metal elements was found in the weld metal of the as-bended pipe.The hot bending process decreases the fraction of acicular ferrite from 66.4 to 47.5%,and the fraction of high angle grain boundary from 76.8 to 67.1%.Therefore,both the type of microstructure and the fraction of ductile microstructures were the influencing factors of weld metal impact toughness,which lead to a reduction from 162 J to 84 J at-40℃.

关键词： K65 hot-bended pipe acicular ferrite tensile strength impact toughness

作者: Liming Dong Yu Zhang Xin Pan Yinbai Wang

作者单位: Institute of Research of Iron and Steel,Sha-steel,Zhangjiagang,Jiangsu,China,215625

会议类型: 国际会议

会议名称: Energy Materials 2014(第一届能源材料国际会议)

会议地点: 西安

会议语种:英文

页码: 721-728

在线出版日期: 2014-11-04（万方平台首次上网日期，不代表论文的发表时间）