摘要
用光学显微镜、扫描电镜、俄歇能谱等方法对 F31 6不锈钢变径管开裂件进行了失效原因分析。结果表明 ,在高温高压的服役条件下 ,变径管接头焊接热影响区在应力作用下 ,环境介质中 Cl- 污染物是引起穿晶应力腐蚀破裂的主要因素。
Cause of cracking of F316 stainless steel reducer was analyzed by metallography, SEM and AES measurements. Three penetrating cracks were observed in small diameter section of reducer. Long cracks were observed on both inner and outer reducer surfaces. Metallographic examination showed that cracking mode was transgranular stress corrosion cracking (TGSCC) with some braches. SEM fractograph of fracture surface showed typical brittle fracture characteristics. EDAX analysis showed that fracture surface contained a large amount of K, Fe, and some Si, Cr, Ni, S and Cl. AES analysis showed that fracture surface and inner surface in the vicinity of cracks contained Cl and S. Higher percentage of Cl and S was detected on fracture surface. It was concluded that, in high temperature and high pressure working condition, contamination of Cl - in medium was the main environmental factor contributed to cracking of reducer joint heat affected zone under stress.
出处
《腐蚀与防护》
CAS
2000年第2期80-82,共3页
Corrosion & Protection
