摘要
介绍了螺旋埋弧焊管用X65级、壁厚20.62mm热轧板卷的制造方法及产品性能。研究表明,选用低C-Mn-Nb-V为基,适当添加Cu,Ni和Mo等元素,采取超纯净钢冶炼、控制轧制和轧后加速冷却工艺,开发的针状铁素体型X65级、壁厚20.62mm热轧板卷的各项理化性能优良,达到了输气管线技术条件要求。随着板卷厚度的增加,X65级钢的碳当量增加,DWTT断口剪切面积下降。X65级钢的组织为块状铁素体+针状铁素体+少量珠光体+少量M-A岛,随着厚度增加,块状铁素体和珠光体及M-A岛数量增加,且晶粒变大,组织不均匀性和带状组织更加明显,最终导致钢的强度和DWTT性能下降,韧脆转变温度升高。随着板卷厚度增加,异常断口越易出现,断口剪切面积判定难度加大。
Manufacturing methods and mechanical properties of 20.62 mm X65 hot-rolled coils for SSAW pipes were introduced.The research results show that all physical chemical properties of 20.62mm AF-type X65 hot-rolled coils are excellent in case of the chemical composition basing on low carbon-Mn-Nb-V adding Cu,Ni and Mo properly,hyperpure smelting and TMCP technology;increasing with the coil thickness,the carbon equivalent of X65 pipeline steel with same strength ascends,the shearing area ratio of DWTT descends;microstructures of X65 pipeline steel consist of solid ferrite,acicular ferrite and a small amount of pearlite and M-A island,with the increment of coil thickness,the volume percentage of solid ferrite pearlite and M-A island increases,the grain size coarsens,structural heterogenity and band structure expand which leads to descend of yield strength and DWTT property and ascend of ductile-brittle transiton temperature,abnormal fracture appears more often and valuation of fracture shearing area ration becomes more difficult.
出处
《焊管》
2008年第3期48-51,共4页
Welded Pipe and Tube
