摘要
对淬火后F22钢进行不同温度(640、670℃)和保温时间(6、12、18、24、30、40 h)的回火处理,研究了回火工艺对其组织和性能的影响。结果表明,回火温度越高、保温时间越长,F22钢的硬度、强度下降,塑性指标上升。回火时间低于18 h时,回火温度越高、保温时间越长,则冲击性能越好。回火时间高于18 h时,回火温度越高、保温时间越长,则冲击性能越差。回火温度越高,碳更容易从α-Fe固溶体析出,且随回火时间延长,马氏体板条结构逐渐分解,碳化物析出长大趋于均匀化,但回火时间超过18 h后,碳化物会向晶界聚集,导致冲击性能下降。经640℃×18 h回火后,F22钢综合力学性能最佳,硬度满足≤22 HRC要求,屈服强度达到最大630 MPa,且伸长率、断面收缩率和-59℃冲击吸收能量较高,分别为25%、65%和268 J。对回火温度和保温时间进行综合调控,可使F22钢达到相近的组织和性能,考虑生产效率可以采用高温短时回火,考虑综合性能稳定性可在较低温长时回火。
F22 steel after quenching was subjected to tempering treatment at different temperatures(640,670℃)and holding time(6,12,18,24,30,40 h)to investigate the effect of tempering processes on its microstructure and properties.The results show that with the increase of tempering temperature and holding time,the hardness and strength of the F22 steel decrease,while the plasticity indicators increase.When the tempering time is less than 18 h,higher tempering temperatures and longer holding times result in better impact properties.However,when the tempering time exceeds 18 h,higher tempering temperature and longer holding time result in worse impact properties.A higher tempering temperature makes it easier for carbon to precipitate from the α-Fe solid solution.With the prolonging of tempering time,the martensitic lath structure gradually decomposes,and the precipitation and growth of carbides tend to become more uniform.However,when the tempering time exceeds 18 h,the carbides aggregate at grain boundaries,resulting in a decline in impact properties.After tempering at 640℃for 18 h,the F22 steel achieves the optimal comprehensive mechanical properties.The hardness meets the requirement of≤22 HRC,the yield strength reaches the maximum of 630 MPa,and the elongation,reduction of area and impact absorbed energy at-59℃are relatively high,with values of 25%,65%,and 268 J,respectively.By comprehensively adjusting the tempering temperature and holding time,the F22 steel can achieve similar microstructures and properties.For higher production efficiency,high-temperature short-time tempering can be adopted,while for better stability of comprehensive properties,lower-temperature long-time tempering is recommended.
作者
许津津
屈志明
周东亮
雷强伟
Xu Jinjin;Qu Zhiming;Zhou Dongliang;Lei Qiangwei(Rongsheng Machinery Manufacture Ltd.of Huabei Oilfield,Hebei,Renqiu Hebei 062552,China;Hebei Well Control and Wellhead Equipment Technology Innovation Center,Hebei,Renqiu Hebei 062552,China)
出处
《金属热处理》
北大核心
2025年第12期199-203,共5页
Heat Treatment of Metals
关键词
F22钢
回火温度
回火时间
力学性能
微观组织
F22 steel
tempering temperature
tempering time
mechanical properties
microstructure
