金属材料与冶金工程第51卷第1期42MnMo7无缝钢管开裂分析黄佑启（衡阳华菱钢管有限公司，湖南衡阳421001）摘要：通过化学成分分析、金相检验和扫描电镜观察等方法，对42MnMo7地质钻杆用无缝钢管在拉伸试验过程中出现的夹持端开裂原因进行了分析。结果表明：材料成分正常，非金属夹杂物控制在较低水平；但裂纹附近的金相组织分析发现钢管内壁存在马氏体等异常组织，并呈现明显的自回火特征，冲击断口呈现典型的解理断口形貌。经调查发现，生产过程中高压水除鳞水环故障导致冷却水从管端进行入钢管内壁，使钢管内壁局部发生马氏体转变，严重部位甚至出现了淬火裂纹，从而导致材料性能恶化，在受到夹持力时发生开裂或二次扩展，最后作者对此提出了相应的改进措施和建议。关键词：地质钻杆管；淬火裂纹；马氏体转变；自回火中图分类号：TG306；TG335.1文献标识码：A文章编号：2095-5014（2023）01-0020-0542MnMo7SeamlessSteelPipeCrackingAnalysisHUANGYouqi（HengyangValinSteelTubeCo.，Ltd.，Hengyang421001，China）ABSTRACT：Throughchemicalcompositionanalysis，metallographicinspectionandscanningelectronmicroscopyobservation，thecausesofcrackingattheclampingendoftheseamlesssteelpipefor42MnMo7geologicaldrillrodduringtensiletestwereanalyzed.Theresultsshowthatthecompositionofthematerialisnormal，andthenon-metallicinclusionsarecontrolledatalowlevel，butthemetallographicstructureanalysisnearthecrackfindsthatthereareabnormalstructuressuchasmartensiteontheinnerwallofthesteelpipe，thereareobviousself-temperingcharacteristics，andtheimpactfractureshowsatypicalcleavagefracturemorphology.Investigationshowsthatthefailureofthehigh-pressurewaterdescalingwaterring，transfersthecoolingwaterfromtheendofthepipeintotheinnerwallofthesteelpipe，sothatthemaltensitictransformationoccurslocallyontheinnerwallofthesteelpipe，andeventhequenchingcrackappearsintheworseparts，resultingindeteriorationofmaterialpropertiesandcrackingorsecondaryexpansionwhensubjectedtoclampingforce.Attheend，theauthorputforwardcorrespondingmeasuresandsuggestionsforthis.KEYWORDS：geologicaldrillpipe；quenchingcrack；martensitictransformation；self-tempering收稿日期：2022-04-05作者简介：黄佑...
