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对25Mn钢铸坯辗扩后环件进行不同温度的再加热,借助光学显微镜观察组织以及利用扫描电镜和电子背散射衍射技术分析晶粒取向差角分布、织构演化过程和拉伸与冲击试样断口形貌。结果表明,加热温度升高,晶粒尺寸增大趋势明显,660℃时大约2/3的晶粒平均直径为16~28μm,但基本呈正态分布特征;高温条件下,亚晶界通过回复作用不断吸收位错,晶界取向差角向大角度晶界迁移的比例增加。反极图结果表明织构形态主要为{001}<110>,600℃时织构强度高,伴有{112}<110>组分织构;随着再加热温度升高织构强度明显减弱。所测定试样力学性能均较高,拉伸断口韧窝明显,且在660℃时韧窝直径大、塑性最好,断面收缩率达到了58.3%,呈韧窝断裂形式。冲击试样断口具有少量解理平台和撕裂棱。
The reheating of the ring after hot rolling at 25Mn steel was carried out at different temperatures. The microstructures of the rings were observed by light microscopy. The distribution of grain orientation difference, texture evolution and tensile and impact tests were analyzed by scanning electron microscopy and electron backscatter diffraction Fracture morphology. The results show that when the heating temperature is increased, the grain size increases obviously. The average grain size of about 2/3 at 660 ℃ is 16 ~ 28μm, but it is basically normal distribution. Under high temperature, The role of continuous absorption of dislocations, the grain boundary orientation angle to the high-angle grain boundary migration increased. The results of the inverse pole diagram show that the texture morphology is mainly {001} <110>, the texture strength is high at 600 ℃ with the texture of {112} <110>, and the texture intensity is obviously weakened with the reheating temperature . The mechanical properties of the samples tested were high, the tensile fracture dimples were obvious, and the dimple diameter was the best at 660 ℃. The shrinkage rate reached 58.3%, which was dimple fracture. Impact specimen fracture with a small amount of cleavage platform and tear edge.