核电管道不锈钢中σ相的退火消除及脆性恢复  

Annealing Induced Removing ofσPhase and Recovery of Embrittlement in Stainless Steel Used for Nuclear Power Plant Pipes

作　　者：王永强[1] 李娜[2] 杨滨[3] 孙立[2] 林苏华[2] 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243002 [2]安徽工业大学冶金工程学院,安徽马鞍山243002 [3]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《材料工程》2016年第5期29-36,共8页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(51501001);安徽省自然科学基金资助项目(1508085QE102);国家高技术研究发展计划(863计划)资助项目(2012AA03A507)

摘　　要：在获得σ相析出显著恶化核电主管道铸造奥氏体不锈钢Z3CN20.09M冲击韧性的基础上,采用等温退火、光学显微镜（OM）、扫描电镜（SEM）等研究了消除σ相的热处理工艺及机理。结果表明：850-1000℃等温退火一定时间,σ相可完全消除,此温度范围内发生σ→α转变,但退火温度越低,所需时间越长,反之越短。这是因为温度低,合金元素扩散速率低,相转变缓慢;而温度升高,合金元素扩散速率加快且相转变驱动力提高,σ相转变速率增加,转变时间缩短。综合考虑,950℃等温退火0.5h为最佳热处理工艺参数。经此工艺处理后,时效（含σ相）试样的力学性能得到完全恢复,σ相的脆化影响消除。The significant deterioration effect of σ phase precipitation on the room temperature impact toughness of Z3CN20.09M cast austenite stainless steel used for primary coolant pipe of nuclear power plant was investigated. On the base of above results, the heat treatment process and mechanism of eliminating of σ phase in stainless steel by means of isothermal annealing technology, optical micro- scope （OM） and scanning electron microscope （SEM） were studied. The results show that the precipi- tated a phase can be completely eliminated by the transformation σ-a when the aged specimens are isothermally annealed at 850-1000℃ for a period of time, but the lower annealing temperature is, the longer time required, and vice versa. The diffusion rate of alloying elements is slow when temperature is low,so the transformation of σ phases is also slow. With the increase of temperature, the diffusion rate of alloying elements accelerates and the driving force of σ phases transformation into a phases in- creases, so the transformation of σ phases becomes higher,thus the transformation time is short. After comprehensive consideration, isothermal annealing at 950℃ for 0. 5h is an optimum heat treatment process parameter. The mechanical property of aged Z3CN20.09M specimens after annealed at 950℃ for 0. 5h can be completely recovered. The annealing process eliminates embrittlement effect of phase on toughness of aged Z3CN20.09M specimens.

关 键 词：铸造奥氏体不锈钢 Σ相 冲击韧性 退火 脆性恢复 

分 类 号：TG142.71[一般工业技术—材料科学与工程]