摘要
核电站主管道奥氏体不锈钢焊缝由于长期在其热老化敏感温度下运行,在服役过程中存在热老化脆化趋向。本文对锻造316LN不锈钢主管道的焊缝在325、365和400℃下15000 h的加速热老化进行试验,并通过TEM研究了焊缝的微观组织变化,采用纳米压入试验和冲击试验对热老化过程中焊缝冲击性能和显微硬度变化进行了研究,使用SEM观察了冲击断口形貌。结果表明:热老化过程中焊缝内铁素体相发生了调幅分解和G相析出;随着热老化时间增加和温度升高,焊缝中铁素体相显微硬度快速增加,奥氏体相未发生改变,焊缝的冲击韧性显著下降。
The weld seam of Austenitic stainless steel in nuclear primary pipe was susceptible to thermal aging embrittlement at reactor operating temperature. The thermal aging experiments of nuclear primary pipe material 316 LN stainless steel weld were performed at 325℃, 365℃ and 400℃ for 15000 h. TEM was utilized to observe the microstructure. A nano-indenter test and Charpy impact test were used to study the change of impact behavior and microhardness.The results indicate that spinodal decomposition and G-phase precipitation in the ferrite are observed after thermal aging. Large increase in the microhardness of ferrite phase is observed with no change in austenite hardness. The impact toughness of weld seam decreases with the increase of aging time and temperature.
出处
《热加工工艺》
CSCD
北大核心
2016年第1期27-29,33,共4页
Hot Working Technology
基金
国家科技重大专项资助项目(2011ZX06004-002)
