CE3MN双相不锈钢铸件裂纹成因与预防  

Causes and Prevention of Cracks in CE3MN Duplex Stainless Steel Castings

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作  者:苏学虎 SU Xue-hu(Jiangsu Wanheng Casting lndustry Co.,Ltd.,Yancheng 224000,Jiangsu,China)

机构地区:[1]江苏万恒铸业有限公司,江苏盐城224000

出  处:《铸造》2024年第9期1262-1272,共11页Foundry

摘  要:针对30″-300 Lb上装式球阀阀体用CE3MN铸造超级双相不锈钢材质,利用FactSage8.2热力学计算软件以及FSstel钢铁数据库,并结合光学显微镜、扫描电镜和能谱仪以及X射线衍射仪等试验手段,研究分析了CE3MN材质铸件在固溶处理之前切割铸态冒口时所产生的裂纹原因。结果表明:CE3MN铸件在脆性相析出的敏感温度范围以内缓慢加热或缓慢冷却过程中,由于铸造成分偏析严重而产生大量富Cr、Mo的有害金属间化合物σ相,主要以短棒状、细针状弥散分布于铁素体基体内或以长链状、条带状、珊瑚状、(σ+γ_(2))胞状以及魏氏组织长针状等形式分布于α/γ相界处。生产实践表明:在气割CE3MN铸件冒口之前,毛坯预先进行固溶处理以消除铸态脆性σ相,抑制裂纹形成和扩展,或者利用锯床先冷锯切铸态冒口后再进行固溶处理,可从根本上规避产生裂纹的温度因素。For the CE3MN cast super duplex stainless steel used in the valve body of 30″-300 Lb up-mounted ball valve,the causes of crack formation in the CE3MN duplex stainless steel castings during cutting the as-cast risers before solid solution treatment were investigated by using the FactSage8.2 thermodynamic calculation software and FSstel professional database combined with optical microscopy(OM),scanning electron microscopy and accompanying energy dispersive spectroscopy(SEM&EDS),X-Ray diffraction(XRD)and other microstructure characterization instruments in this paper.The results demonstrate that in the processes of slow heating or slow cooling within the sensitive temperature range of a series of brittle precipitated phases,a large number of the Cr and Mo element rich intermetallic compound sigma phases,which detrimental to the performance of CE3MN duplex stainless steel castings,may generate due to severe segregation of chemical components,and the intermetallic phases dispersedly distribute in the ferrite matrix in forms of short rodlike and fine needle-like structures,or distribute at the boundaries of α/γ phases in forms of long chain-like,banding-like,coral-like,(σ+γ_(2))cellular shape-like,long needle-like widmannstatten structure and so on.Production practice further showed that the solid solution treatment was carried out in advance to eliminate the possible as-cast brittleσphases and inhibit the formation and expansion of cracks before cutting the risers of CE3MN duplex stainless steel castings,or firstly using sawing machine to cut the as-cast risers under cold condition and then carry out the solid solution treatment,the temperature factor causing cracks could be fundamentally avoided.

关 键 词:CE3MN铸造双相不锈钢 热力学计算 凝固与相变 铸态组织 Σ相 裂纹 

分 类 号:TG142.71[一般工业技术—材料科学与工程]

 

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