輕水式反應器(Light Water Reactor, LWR)的結構組件,隨著運轉時間增加,必然於異材金屬銲件發生應力腐蝕(Stress Corrosion Cracking, SCC)問題。由於國內電廠結構組件及銲件使用沃斯田不鏽鋼與鎳基合金,同樣面臨SCC問題,故值得針對此類銲件進行SCC現象研究。本實驗於模擬沸水式反應器水循環系統中,應用Creviced Bent Beam方法,針對304不鏽鋼與82合金異材銲件的應力腐蝕龜裂現象進行研究,探討經過銲後熱處理(Post-weld Heat Treatment, PWHT),以及再經氧化鋯抑制性被覆(Inhibitive Protective Coating)處理的銲件,其銲道附近的SCC敏感性及其裂縫起始和成長行為。結果顯示接受被覆處理試片較未接受被覆處理的試片,前者在裂縫數量上較多,但長度較短;主因是不均勻被覆導致。此外,部分證據指出孔蝕可能為裂縫的起始現象。
Stress corrosion cracking (SCC) in the structural components of light water reactors (LWRs) is inevitable as the operation times of these reactors increase. Since austenitic stainless steels and nickel-based alloys are extensively used as structural materials in nuclear reactors in Taiwan, issues of SCC on dissimilar metal weld joints are of great importance. In this investigation, Creviced Bent Beam (CBB) method was introduced to study SCC initiation and growth behavior in 304 S.S – Alloy 82 dissimilar metal weldment test samples in simulated boiling water reactor (BWR) environments. Specimens with, without post-weld heat treatments (PWHT), and received ZrO2 inhibitive protective coating (IPC) treatments were prepared and examined. Results indicated that number of cracks on coating specimens is more than without coating ones, but average length of cracks of former ones is shorter. Another results implied that pitting is a precursor of cracks