X80管线钢待温过程中的析出行为研究.pdfVIP

X80管线钢待温过程中的析出行为研究 牛 涛 安成钢 姜永文 吴新朗 张彩霞 代晓莉 (首钢技术研究院) (首钢股份公司迁安钢铁公司) 摘 要 利用应力松弛方法研究了X80管线钢的PrI．r曲线，结合动力学计算对待温过程中的析出粒子尺寸 演变进行模拟，并利用透射电镜研究了X80管线钢在不同待温时间下Nb(C，N)沉淀析出的规律。结果表 明，试验用 X80管线钢的PTr曲线为典型的C型，析出的鼻尖温度约为900℃，孕育时间约 为5S；动力 学计算表明，析出粒子的平均直径随着待温时间的延长而明显增加；在 X80管线钢的实际生产中，950oC 下待温约 90s后，60am的析出粒子比例明显提高，与动力学计算结果基本吻合；固溶铌含量的增加可有 效降低晶界迁移率，从而通过溶质拖曳作用抑制再结晶的进行。因此 ，在不提高温度的情况下，适当缩短 待温时间可减少铌在待温过程中的高温析出，从而提高 X80管线钢的强韧性。 关键词 管线钢 待温 析出 再结晶 溶质拖曳 Research ofPrecipitationBehaviorduringHolding ProcessofX80PipelineSteel NIU Tao ANChenggang JIANGYongwen WU Xinlang ZHANG Caixia DAIXiaoli (ShougangResearchInstituteofTechnology) fShougangQiananIronSteelCompany) Abstract I)1[TI’(Precipitation-Temperature—Time)curveofX80pipelinesteelwasobtainedbystress relaxationmethod．Theevolution ofprecipitateparticlesizeduringholdingprocesswassimulated combinedwithkineticcalculation，andtheprecipitationofNb(C，N)inX80pipelinesteelwith differentholdingtimewasstudied byTEM．Theresultsshowedthattheshapeof阿 curvewas typical“C”typewith thenosetemperatureof900 oC and incubation timeofabout5s．Kinetic calculationresuhsshowed thattheaverageparticle size increased obviouslywith theextension of holdingtime．IntheindustrialproductionofX80pipelinesteel，itwasobservedthatafterholdingfor 90Sat950 ℃ ，theproportionofprecipitateparticleslargerthan60 nm increasedsignificantly， whichbasicallyagreedwiththekineticcalculationresults．Grainboundarymigrationcouldbeslowed down effectivelywiththeincreaseofdissolvedNb，whichinhibitedrecrystallizationbysolutedrag effect．Therefore，by properly shortening holding timewithout increasing holding temperature， precipitationofNb athightemperaturecouldbereducedduringholdingprocess，nad thestrength andtoughnessofsteelcouldbeimprovedaccordingly． KeyWords pipelinesteel，holdingprocess，precipitatio