特殊钢大方坯碳偏析遗传性及其轧材组织特征研究

Carbon Macrosegregation Heredity of Cast Bloom of Special Steel and Microstructure Characteristics of Its Rolled Bar

通过跟踪特钢20CrMnTi和42CrMo的生产,分别对同一炉次铸坯和轧材取样,分析其低倍组织和碳偏析。结果表明:铸坯中的碳偏析会遗传到轧材,轧材出现锭型偏析,轧材低倍组织与铸坯凝固结构相关。针对轧材的锭型偏析区域,用光学显微镜观察其显微组织,发现锭型内外区域的显微组织不同,并且20CrMnTi的轧材存在带状组织,这对组织性能的均匀性不利,影响成品质量。

We followed the production of 20CrMnTi and 42CrMo steel and took the samples of cast bloom and rolled bar at the same batch.By analyzing their macrostructure and carbon macrosegregation,we found the carbon segregation had definitely inherit characteristics from cast bloom to its rolled bar,which led to segregation with ingot shape in the rolled bar,and the macrostructure of rolled bar was related with solidification structure of cast bloom.We observed the segregation in the rolled bar under the optical microscope and found that the rolled bar had different macrostructure in and out of the ingot-shape area.We also found banded structure in the 20CrMnTi steel which was bad for homogeneity and finally influenced the quality of finished products.