以一种热冲压成形钢22MnB5为试验材料,将膨胀法与金相法、硬度法结合,在热膨胀相变仪上测量了该钢的临界转变点,并获得材料的连续冷却转变曲线.结果表明:当冷却速率为0.1℃/s时,显微组织为粗大的铁素体与珠光体;当冷却速率为0.5～5℃/s时,显微组织以贝氏体为主,同时有少量的珠光体和铁素体;当冷却速率大于7.5℃/s时,显微组织为马氏体和贝氏体;当冷却速率大于20℃/s时,贝氏体转变基本结束,全部转变为马氏体.维氏硬度随冷却速率的增大呈增大趋势.
Taking a hot stamping steel 22MnB5 as the test material,the critical transformation point of the steel was measured on the quenching phase change instrument by combining the expansion method with the metallographic method and the hardness method,and the continuous cooling transformation curve of the material was obtained.The results show that when the cooling rate was 0.1℃/s,the microstructure was coarse ferrite and pearlite.When the cooling rate was 0.5-5℃/s,the microstructure was mainly bainite,with a small amount of pearlite and ferrite.When the cooling rate was greater than 7.5℃/s,the microstructure was martensite and bainite.When the cooling rate was greater than 20℃/s,the bainite transformation basically ended and all transformed into martensite.Vickers hardness increased with the increase of cooling rate.
雷娜;周志超;杨志权;赵乃胜;沈洁;王明辉
北京首钢股份有限公司, 迁安 064400
热冲压成形钢;连续冷却转变曲线;冷却速率;显微组织;硬度;膨胀曲线
hot stamping forming steel;continuous cooling transformation curve;cooling rate;microstructure;hardness;dilatometric curve
《理化检验-物理分册》 2024 (002)
10-12,16 / 4
10.11973/lhjy-wl202402003
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