偏心度对C型环淬火和深冷处理组织和应力演变影响的数值研究

NUMERICAL STUDY ON EFFECT OF ECCENTRICITY ON THE MICROSTRUCTURE AND STRESS EVOLUTION OF C-RING DURING QUENCHING AND DEEP CRYOGENIC TREATMENT

建立了不同偏心度C型环试样淬火和深冷处理过程的数值模型,探讨了偏心度对C型环试样淬火和深冷处理过程中组织和应力演变的影响。研究表明,在淬火过程中,偏心度越大,试样中残留奥氏体组织分布的不均匀性越明显。深冷处理后,试样中奥氏体分布的不均匀性得到显著改善,偏心度越小,改善效果越明显。深冷处理使试样中残留奥氏体含量减少了约14%。随着偏心度的减小,试样应力演变曲线上的应力峰值发生变化,影响应力峰值的主导因素由热应力转变为相变应力。相比淬火过程,深冷处理过程中的应力演变要平缓得多。无论是淬火还是深冷处理,试样的偏心度越小,其残余应力的分布越均匀。

Multi-field coupled numerical models were established to evaluate the effect of eccentricity on the microstructure and stress evolution of C-ring specimens during quenching and deep cryogenic treatment（ DCT）. The results indicated that, during the quenching process, as the eccentricity of C-ring specimen increased,the inhomogeneous distribution of retained austenite in the specimen was more obviously. After DCT,the inhomogeneous distribution of retained austenite in the specimen was improved remarkably and the smaller eccentricity,the more evident improvement. The content of residual austenite in the specimen after DCT represented a reduction of about 14 %. With the decrease of the eccentricity,the stress peak values on the stress evolution curves were changed and its dominant factor was also changed from the thermal stress to the phase transformation stress.Compared with the quenching process,the stress evolution of specimen during the DCT process was more gently. Whether it is quenching or DCT, the smaller eccentricity is, the more uniform distribution of residual stress will be.