渗碳淬火过程中C形试样组织与畸变演变行为的数值模拟

Numerical simulation of microstructure and distortion evolution behavior of C-type specimens during carburizing and quenching

以18Cr2Ni2MoNbA钢C形试样为对象,采用有限元方法建立了温度场、组织场、应变场的多场耦合模型,研究了C形试样在悬挂方式下渗碳淬火过程中组织与畸变演变行为。结果表明:将计算的畸变结果与实测进行对比,结果吻合良好,C形试样缺口位置的畸变最大,冷却过程中宽度最大处的中心位置与缺口处表面位置之间的最大温差出现在淬火的2.78 s,达到383.437℃;马氏体转变最先是从缺口位置的心部开始,C形试样心部马氏体含量基本都能达到94%以上;淬火时表层马氏体转变滞后于心部,其马氏体转变量受残留奥氏体影响明显低于心部,最终转变量在83%左右。

Taking C-type specimen of 18Cr2Ni2MoNbA steel as the study object,the microstructure and distortion evolution behavior of the C-type specimens under suspension during carburizing and quenching were studied by using finite element method to establish a multi-field coupling model of temperature field,structure field and strain field.The results show that the calculated distortion results are in good agreement with the actual measurements.The maximum distortion is at the notch position of the C-type specimen.The maximum temperature difference between the center position of the maximum width and the surface position of the notch during cooling process appears at 2.78 s and reaches 383.437℃.The martensitic transformation first starts from the core of the notch position,and the content of martensite in the core of C-type specimen can generally reach over 94%.During quenching,the surface martensite transformation of the C-type specimen lags behind the core,the surface martensitic transformation content is significantly lower than that of the core under the influence of retained austenite,and the final transformation content is about 83%.