【摘要】 运用DIL805A热膨胀相变仪对热轧态和退火态22CrMo齿轮钢试样的淬火膨胀性能进行测定,研究了带状组织对钢各向异性的影响,通过光学显微镜、扫描电子显微镜观察并分析显微组织。结果表明,含有带状组织的22CrMo齿轮钢不同方向试样的淬火变形量呈现明显各向异性,垂直于轧制带的膨胀量明显大于轧制带方向,不同带状组织的合金元素富集程度不同,导致相变产生的塑性应变制约相邻带的膨胀变形。热轧态22CrMo齿轮钢淬火膨胀无规律性;而退火钢的淬火膨胀特性有明显规律,奥氏体化保温时间越长,碳化物溶解充分,淬透性越高。更多还原

【Abstract】 Dimensional anisotropy associated with banded structure in hot rolled and annealed gear steel 22 CrMo was investigated by DIL805 A dilatometer.The microstructure was observed and analyzed by OM and SEM.The results show that 22 CrMo gear steel with banded structure display different dilatational characteristics along the rolling direction(RD) and the transverse direction(TD) during quenching.In addition,transverse expansion is significantly greater than that of longitudinal.The mutual constraints have produced plastic strain of phase transformation on account of alloy elements enrichment in different banded structure.The expansion characteristics of the hot rolled steel present irregular fluctuations due to non-equilibrium microstructure,whereas the expansion value of annealed steel is closely related to the heat holding time during austenitizing.The longer holding time is,the greater amount of martensite transformation with the dissolution of carbides gradually is.更多还原