【摘要】 通过控制热处理参数在G55SiMoV钢中获得了不同贝氏体含量的马氏体/贝氏体复相组织,研究了贝氏体含量对其韧性和回火脆性的影响。结果表明:随等温时间延长贝氏体含量增加,等温淬火5 min、15 min、30 min、60 min可分别获得17%、27%、29%、31%的贝氏体。当贝氏体量较多(大于27%)时,马氏体对贝氏体的应变强化效果降低,韧性提高更加显著。300℃以下回火时组织和硬度基本不变;300℃回火时存在回火脆性,该马氏体/贝氏体复合组织钢的回火脆性温度区间几乎不受贝氏体量的影响,但增加贝氏体量可以提高残留奥氏体稳定性,使韧性降幅减小。更多还原

【Abstract】 Martensite /bainite( M /B) dual phase microstructure G55SiMoV steel with different bainite content was produced via controlling the austempering process.The effect of bainite content on toughness and temper brittleness of the M /B microstructure steel was investigated.The results show that the bainite content increases with the increasing of austempering time,and the bainite content is 17%,27%,29% and 31% for the austempering time of 5 min,30 min and 60 min,respectively.The toughness improvement is more significant when the bainite content is high( ≥27%),as the result of the reduction of strain strengthening of bainite.The microstructure and hardness of samples tempered below 300 ℃ can keep stable.Temper brittleness occurs at 300 ℃.The temperature range of temper brittleness is almost not affected by the bainite content,but the decrease degree of toughness can be reduced with the bainite content increasing,which improves the stability of residual austenite.更多还原