在役超临界机组P91材质主蒸汽管道失效分析
|
摘要
采用显微组织观察和力学性能测试等方法,对某火电厂服役时间约32 000h的在役超临界机组P91材质主蒸汽管道弯头焊接接头进行取样分析研究。结果表明,经过长时间服役后,弯头焊缝内表面均出现裂纹,且裂纹均出现在焊缝与母材的交界处,呈环向开裂。材料抗拉强度、硬度及冲击功等各项力学性能虽满足相关标准要求,但显微组织发生了蠕变损伤。设备发生泄漏的主要原因,是由于焊接接头处不同材料力学性能不同,进而在高温条件下发生蠕变变形,变形的不协调使得热影响区产生裂纹。
The microstructure observation and mechanical property test were used to analyze welded joints of main steam pipe elbow(P91steel)after about 32 000 hin service from a supercritical unit in a thermal power plant.The results show that circumferential cracks were found at junction between weld and base metal on the inner surface of the elbow after a long period of service.The mechanical properties such as tensile strength,hardness and impact energy of main steam pipe material met the requirements of relevant standards,but the microstructure had creep damage.The main reason for equipment leakage was due to different mechanical properties of welded joints with different materials,and then the pipe initiated creep deformation under high temperature leading to heat affected zone cracking.
The microstructure observation and mechanical property test were used to analyze welded joints of main steam pipe elbow(P91steel)after about 32 000 hin service from a supercritical unit in a thermal power plant.The results show that circumferential cracks were found at junction between weld and base metal on the inner surface of the elbow after a long period of service.The mechanical properties such as tensile strength,hardness and impact energy of main steam pipe material met the requirements of relevant standards,but the microstructure had creep damage.The main reason for equipment leakage was due to different mechanical properties of welded joints with different materials,and then the pipe initiated creep deformation under high temperature leading to heat affected zone cracking.
引文
[1]HALD J.Creep and Fracture in High Temperature Components Design and Life Assessment Issues[M].Lancaster:DEStech Publication Inc.,2005.
[2]涂善东,轩福贞,王卫泽.高温蠕变与断裂评价的若干问题[J].金属学报,2009,45(7):781-787.(TU Shan-dong,XUAN Fu-zhen,WANG Wei-ze.Some Critical Issues in Creep and Fracture Assessment at High Temperature[J].Journal of Metal Research,2009,45(7):781-787.)
[3]涂善东.高温结构完整性原理[M].北京:科学出版社,2003.(TU Shan-dong.High Temperature Structural Integrity Principle[M].Beijing:Science Press,2003.)
[4]巩建鸣,涂善东,凌祥,等.服役的HK40炉管抗蠕变裂纹扩展能力[J].石油化工设备,1999,28(3):6-10.(GONG Jian-ming,TU Shan-dong,LING Xiang,et al.Resistance of HK40 Furnace Tubes Against Creep Crack Growth[J].Petro-chemical Equipment,1999,28(3):6-10.)
[5]郭秋月,刘峰.奥氏体不锈钢316L蠕变裂纹失稳研究[J].石油化工设备,2008,37(增刊):4-6.(GUO Qiu-yue,LIU Feng.Assessment for Creep Crack Fracture of 316LBased on TDFAD[J].Petrochemical Equipment,2008,37(S):4-6.)
[6]Yatomi M,Fuji A,Ken-ichi I K,et al.Creep Crack Growth of P92 Welds[C]//ASME 2008 Pressure Vessels and Piping Conference.American Society of Mechanical Engineers,2008:1207-1214.
[7]Francis J A,Mazur W,Bhadeshia H.Review Type IV Cracking in Ferritic Power Plant Steels[J].Materials Science and Technology,2006,22(12):1387-1395.
[8]GB/T 228.1—2010,金属材料拉伸试验第1部分:室温试验方法[S].(GB/T 228.1—2010,Metallic Materials-Tensile Testing-Part 1:Test Method at Room Temperature[S].)
[9]GB/T 231.1—2009,金属材料布氏硬度试验第1部分:试验方法[S].(GB/T 231.1—2009,Metallic Materials-Brinell Hardness Test-Part 1:Test Methods[S].)
[10]GB/T 229—2007,金属材料夏比摆锤冲击试验方法[S].(GB/T 229—2007,Metallic Materials Charpy Impact Test Method[S].)
[11]SA355/SA-335M ASME Boiler&Pressure Vessel CodeⅡ,Materials Part A Ferrous Material Specifications:Specification for Seamless Ferritic Alloy-steel Pipe for High-temperature Service,2007[S].
[12]DL/T 438—2009,火力发电厂金属技术监督规程[S].(DL/T 438—2009,Thermal Power Plant Metal Technical Supervision[S].Beijing:China Electric Power Press,2009.)
[13]DL/T 868—2004,焊接工艺评定规程[S].(DL/T 868—2004,Welding Procedure Qualification Procedure[S].)
[14]Hald J Hamouda H,Laiarinandrasana L,Piques R.A Local Approach to Creep Fracture by Slow Crack Growth in an MDPE:Damage Modelling[J].International Journal of Pressure Vessels and Piping,2009,86(2-3):228-238.
[15]Davies CM,O’DOWD NP,Nikbin KM,et al.An Analytical and Computational Study of Crack Initiation under Transient Creep Conditions[J].International Journal of Solids and Structures,2007,44(6):1823-1843.
[2]涂善东,轩福贞,王卫泽.高温蠕变与断裂评价的若干问题[J].金属学报,2009,45(7):781-787.(TU Shan-dong,XUAN Fu-zhen,WANG Wei-ze.Some Critical Issues in Creep and Fracture Assessment at High Temperature[J].Journal of Metal Research,2009,45(7):781-787.)
[3]涂善东.高温结构完整性原理[M].北京:科学出版社,2003.(TU Shan-dong.High Temperature Structural Integrity Principle[M].Beijing:Science Press,2003.)
[4]巩建鸣,涂善东,凌祥,等.服役的HK40炉管抗蠕变裂纹扩展能力[J].石油化工设备,1999,28(3):6-10.(GONG Jian-ming,TU Shan-dong,LING Xiang,et al.Resistance of HK40 Furnace Tubes Against Creep Crack Growth[J].Petro-chemical Equipment,1999,28(3):6-10.)
[5]郭秋月,刘峰.奥氏体不锈钢316L蠕变裂纹失稳研究[J].石油化工设备,2008,37(增刊):4-6.(GUO Qiu-yue,LIU Feng.Assessment for Creep Crack Fracture of 316LBased on TDFAD[J].Petrochemical Equipment,2008,37(S):4-6.)
[6]Yatomi M,Fuji A,Ken-ichi I K,et al.Creep Crack Growth of P92 Welds[C]//ASME 2008 Pressure Vessels and Piping Conference.American Society of Mechanical Engineers,2008:1207-1214.
[7]Francis J A,Mazur W,Bhadeshia H.Review Type IV Cracking in Ferritic Power Plant Steels[J].Materials Science and Technology,2006,22(12):1387-1395.
[8]GB/T 228.1—2010,金属材料拉伸试验第1部分:室温试验方法[S].(GB/T 228.1—2010,Metallic Materials-Tensile Testing-Part 1:Test Method at Room Temperature[S].)
[9]GB/T 231.1—2009,金属材料布氏硬度试验第1部分:试验方法[S].(GB/T 231.1—2009,Metallic Materials-Brinell Hardness Test-Part 1:Test Methods[S].)
[10]GB/T 229—2007,金属材料夏比摆锤冲击试验方法[S].(GB/T 229—2007,Metallic Materials Charpy Impact Test Method[S].)
[11]SA355/SA-335M ASME Boiler&Pressure Vessel CodeⅡ,Materials Part A Ferrous Material Specifications:Specification for Seamless Ferritic Alloy-steel Pipe for High-temperature Service,2007[S].
[12]DL/T 438—2009,火力发电厂金属技术监督规程[S].(DL/T 438—2009,Thermal Power Plant Metal Technical Supervision[S].Beijing:China Electric Power Press,2009.)
[13]DL/T 868—2004,焊接工艺评定规程[S].(DL/T 868—2004,Welding Procedure Qualification Procedure[S].)
[14]Hald J Hamouda H,Laiarinandrasana L,Piques R.A Local Approach to Creep Fracture by Slow Crack Growth in an MDPE:Damage Modelling[J].International Journal of Pressure Vessels and Piping,2009,86(2-3):228-238.
[15]Davies CM,O’DOWD NP,Nikbin KM,et al.An Analytical and Computational Study of Crack Initiation under Transient Creep Conditions[J].International Journal of Solids and Structures,2007,44(6):1823-1843.