20CrMnTi钢锻件强度不合格的原因

Cause for 20CrMnTi Steel Forgings Having Unqualified Strengths

经过淬火和低温回火的20CrMnTi钢锻件抗拉和屈服强度不合格。为此,检测了不合格锻件的化学成分、硬度和显微组织。结果表明:锻件的化学成分和硬度均符合要求,其强度性能不合格的原因是淬火加热炉温度均匀性差,导致其奥氏体化不充分,组织中存在不应有的铁素体。

20CrMnTi steel forgings subjected to hardening and low-temperature tempering exhibited unqualified tensile and yield strengths.For this reason,the unqualified forgings were tested for chemical composition,hardness and microstructure.The results showed that both chemical composition and hardness conformed with the requirements,and the cause of their unacceptable strength properties proved to be undesirable ferrite which was present in microstructure and was traced to insufficient austenitizing because of poor uniformity of furnace where heating for hardening was performed.