时效处理对HR3C合金微观组织和冲击韧度的影响
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摘要
采用高温热处理炉对超超临界电站锅炉用HR3C合金进行短时时效和650℃×500h时效,研究了时效对合金微观组织和冲击韧度的影响。结果表明,短时时效后,晶内存在少量一次大块NbCrN相,同时有少量细小的Z相析出。在650℃×500h时效后,晶内析出更多细小的Z相,经短时时效,合金晶内的Z相更多,其弥散强化提高了合金的显微硬度;晶界析出M23C6相并进一步粗化长大,晶界附近有弥散块状的M_(23)C_6相析出。长期时效后,固溶态和短时时效态合金的冲击韧度降低,断口沿晶断裂。
HR3Calloy was treated with aging treatment and long-term aging at 650 ℃for 500 hto analyze influence of aging treatment on the microstructure and impact toughness.The results reveal that a few large bulky NbCrN phase an be observed with precipitation of a little tiny Z-phase particles at innergrain after aging treatment.More Z-phase is precipiated in alloy with aging treatment after long-term aging at 650 ℃ for 500 h,which improves the microhardness by dispersedly strengthening effects.Meanwhile,M_(23)C_6 type carbides are coarsened along the grain boundaries,while some M_(23)C_6 particles are distributed randomly inside the austenitic grain.The impact toughness values of HR3 Calloy with solid solution treatment or aging treatment are decreased after long-term aging,and the fracture morphologies of the notched impact specimens are characterized by intergranular fracture mode.
HR3Calloy was treated with aging treatment and long-term aging at 650 ℃for 500 hto analyze influence of aging treatment on the microstructure and impact toughness.The results reveal that a few large bulky NbCrN phase an be observed with precipitation of a little tiny Z-phase particles at innergrain after aging treatment.More Z-phase is precipiated in alloy with aging treatment after long-term aging at 650 ℃ for 500 h,which improves the microhardness by dispersedly strengthening effects.Meanwhile,M_(23)C_6 type carbides are coarsened along the grain boundaries,while some M_(23)C_6 particles are distributed randomly inside the austenitic grain.The impact toughness values of HR3 Calloy with solid solution treatment or aging treatment are decreased after long-term aging,and the fracture morphologies of the notched impact specimens are characterized by intergranular fracture mode.
引文
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[2]CHENG S C,LIU Z D,BAO H S,et al.Investigation of bar-like carbides in HR3Cboiler steel[J].Materials Science Forum,2010,639-642:3 105-3 110.
[3]刘俊建,陈国宏,王家庆,等.时效热处理对HR3C钢组织结构及力学性能的影响[J].合肥工业大学学报,2011,34(1):47-51.
[4]陈国宏,潘家栋,王家庆,等.650℃时效HR3C耐热钢的显微组织与高温拉伸性能[J].材料热处理学报,2014,35(2):104-109.
[5]殷尊,蔡辉,刘鸿国.新型耐热钢HR3C在超超临界机组高温服役25 000h后的性能研究[J].中国电机工程学报,2011,31(29):103-109.
[6]沈琦,刘鸿国,唐丽英.超超临界机组新型不锈钢super304H、HR3C运行5 400h后的性能试验[J].电力建设,2009,30(9):62-66.
[7]方园园,赵杰,李晓娜.HR3C钢高温时效过程中的析出相[J].金属学报,2010,46(7):844-849.
[8]PENG B C,ZHANG H X,HONG J,et al.Effect of aging on the impact toughness of 25Cr-20Ni-Nb-N steel[J].Materials Science and Engineering,2010,A527:1 957-1 961.
[9]杜宝帅,魏玉忠,张忠文,等.高温服役4.2万小时超超临界机组用HR3C钢组织与性能[J].材料热处理学报,2014,35(12):84-89.
[10]田丽倩.奥氏体耐热钢HR3C的显微组织和力学性能研究[D].山东淄博:山东理工大学,2012.
[11]王敬忠,刘正东,程世长,等.高温时效对S31042钢管室温拉伸性能的影响[J].特殊钢,2011,32(3):61-32.
[12]CHI C Y,YU H Y,DONG J X,et al.The precipitation strengthening behavior of Cu-rich phase in Nb contained advanced Fe-Cr-Ni type austenitic heat resistant steel for USC power plant application[J].Progress in Natural Science:Materials International,2012,22(3):175-185.
[13]亨利G,豪斯特曼D.宏观断口学及微观断口学[M].北京:机械工艺出版社,1990.
[14]李俊林,杨兴博,汪东明,等.锅炉用钢及其焊接[M].哈尔滨:黑龙江科学技术出版社,1988.
[15]彭志方,任文,杨超,等.HR3C钢运行过热器管的脆化与晶界M23C6相参量演化的关系[J].金属学报,2015,51(11):1 325-1 332.