冷却工艺对抗大变形管线钢X70HD热涂敷性能的影响  

Effect of Cooling Process on Properties of Heat Coated X70HD Pipeline Steel with Severe Deformability Resistance

作　　者：吴清明[1] 刘永龙[1] 熊祥江[1] 陈奇明[1] 李中平[1] 陈小伟 

机构地区：[1]湘潭钢铁集团有限公司,湖南湘潭411101 [2]渤海石油装备巨龙钢管有限公司,河北青县062650

出　　处：《热处理技术与装备》2012年第1期25-29,共5页Heat Treatment Technology and Equipment

摘　　要：抗大变形管线钢加热并保温一段时间后,钢管力学性能将发生变化,通常屈服强度、屈强比升高,均匀延伸率降低,应力-应变曲线形状改变等,这些性能变化将降低钢管的抵抗变形的能力。利用扫描电镜等设备研究了冷却工艺对21 mm X70HD抗大变形管线钢组织、性能和应变时效硬化的影响。结果表明,随开始冷却温度的降低,先共析铁素体含量逐渐增加,贝氏体含量逐渐降低,贝氏体由粒状逐渐向板条状转变,当开始冷却温度在700℃时,钢板具有最佳的综合力学性能,试验钢板通过制成1016 mm钢管,钢管在200℃时效保温5 min下,纵向屈服强度Rt0.5为509 MPa,抗拉强度Rm为692 MPa,延伸率为42%,屈强比Rt0.5/Rm为0.73,Rt1.5/Rt0.5为1.19、Rt2.0/Rt1.0为1.10,均匀变形伸长率达到9.5%。The mechanical properties of X70HD pipeline steel with severe deformability resistance will change after heating and holding some times,usually YS（yield strength） and Y/T（yield rario） rise,UEL（uniform elongation） reduces,the curve shape of stress-strain varies and so on,which will reduce the pipeline deformability resistance.The effects of the cooling process on the microstructure,mechanical properties and ageing induration for 21mm X70HD pipeline with severe deformability steel are studied by the analysis of SEM.The results show that the content of pro-eutectoid ferrite increases,and the content of bainite reduces and granular bainite gradually change to board strips,with the decrease of the start cooling temperature.When the start cooling temperature is about 700 ℃,steel plats have excellent integrated mechanical properties.After making the pipe 1016 mm,it heat at 200 ℃ and ageing induration 5 min,the longitudinal yield strength：Rt0.5=497 Mpa,tensile strength Rm=695 Mpa,elongation A=41.5%,yield ratio Rt0.5/Rm=0.72,Rt1.5/Rt0.5=1.24,Rt2.0/Rt1.0=1.09,UEL=9.5% properties.

关 键 词：X70HD钢 抗大变形 应变时效 均匀延伸率 

分 类 号：TG174.44[金属学及工艺—金属表面处理]