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采用一种新的HOP(Heat on-line partitioning)技术使X80管线钢得到了(B+M/A)复相组织。与普通X80管线钢相比,(B+M/A)X80管线钢在满足强度要求的基础上,有更优良的变形能力,其屈强比为0.80,均匀伸长率为10.3%,形变强化指数为0.14,满足了大变形管线钢的技术要求,适合应用于地震带、冻土等大位移的油气管线服役环境。显微组织分析表明,在(B+M/A)X80管线钢中,回火态贝氏体和细微化M/A间的复合作用,赋予材料高的强、塑特性。其中贝氏体基体中碳化物的析出和马氏体的形成,保证了材料具有较高的强度。贝氏体基体回火软化、位错恢复和薄片状或块状残留奥氏体的形成,使得材料具有良好的塑性变形能力。
A new HOP (Heat on-line partitioning) technology was adopted to obtain (B + M / A) complex phase microstructure of X80 pipeline steel. Compared with ordinary X80 pipeline steel, (B + M / A) X80 pipeline steel has better deformation ability on the basis of meeting the strength requirements. The yield strength ratio is 0.80, the uniform elongation rate is 10.3% Index of 0.14, to meet the technical requirements of large deformation of pipeline steel, suitable for seismic zone, frozen soil and other large displacement oil and gas pipeline service environment. Microstructure analysis shows that the composite effect of tempering bainite and micro-M / A in (B + M / A) X80 pipeline steel gives the material high strength and plastic properties. The precipitation of carbides and the formation of martensite in the bainite matrix ensure the high strength of the material. Bainite matrix tempering softening, dislocation recovery and the formation of lamellar or massive residual austenite, making the material has good plastic deformation capacity.