魏氏组织对焊接接头缝隙腐蚀的影响  

Effect of widmanstatten structure on crevice corrosion behavior of welded joint

作　　者：刘超[1] 张星星 刘泉林[1] 高克玮[1] 

机构地区：[1]北京科技大学材料科学与工程学院

出　　处：《金属热处理》2018年第2期111-115,共5页Heat Treatment of Metals

基　　金：国家自然科学基金(51271024)

摘　　要：利用浸泡试验研究了Q235钢氩弧焊焊接接头在90℃地下水模拟溶液中的缝隙腐蚀行为,通过宏观及微观形貌观察、金相分析、表面轮廓分析和成分分析等方法表征了缝隙腐蚀特征,并借助原位腐蚀试验分析了魏氏组织对缝隙腐蚀行为的影响。结果表明：焊接接头焊缝处存在大量的魏氏组织,缝隙内部的魏氏组织在较高温度下优先发生腐蚀,腐蚀致使缝隙内部焊缝区出现大量坑洞。其原因是：在魏氏组织中,珠光体和先共析铁素体之间的晶界为富碳层,与贫碳的先共析铁素体构成微原电池,导致点蚀在先共析铁素体上形核并发展。Crevice corrosion behavior of Q235-tungsten inert gas （TIG） welded joint was studied in a simulated groundwater at 90 ℃ throughimmersion test. The crevice corrosion behaviors were characterized based on macro and micro morphology observation, metallographicexamination, surface-profile and component analysis. The effect of the widmanstatten structure on crevice corrosion behavior was analyzed.The results show that the welded joint contains large amount of widmanstatten structure. Crevice corrosion preferentially occurs in thewiamanstatten structure when immersed in the test water at 90 ℃ and some corrosion pits appears in the welded joint location. It is indicatedthat the grain boundary between pearlite and proeutectoid ferrite is a carbon-rich layer, and proeutectoid ferrite is a carbon-poor area,therefore, a galvanic cell is formed between the grain boundary and the proeutectoid ferrite, which leads to prior nucleation and growth ofpitting on the proeutectoid ferrite.

关 键 词：Q235钢 焊接接头 缝隙腐蚀 魏氏组织 

分 类 号：TG457.11[金属学及工艺—焊接]