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采用Ａ００２ ， Ａ１３２ 和Ａ３０２ 三种焊条以及（６００ ，８００ 和１０５０）０Ｃ×６ｈ 三种焊后热处理方式，研究了３０４ 钢不同焊缝的环境断裂行为。试验是用悬臂梁弯曲试样在室温０ ．５ｍｏｌ／ＬＮａＣｌ＋ ２ ．５ｍｏｌ／ＬＨ２ＳＯ４ 溶液中进行的。测定了各种焊缝的ｄａ／ｄｔ ～Ｋ１ 曲线，并作了浸蚀试验、腐蚀电化学试验和断口分析。结果表明：焊缝的ＫＩＳＣＣ 为３０ ～３８ＭＰａｍ １／２，按Ａ００２，Ａ３０２ 和Ａ１３２顺序递增，只及母材的（６２ ～７９）％ ；其裂缝扩展速率ｄａ／ｄｔ 达（５ ～７） ×１０－ ６ ｍ ｍｓ－ １ ，为母材的２ ．８ ～３ ．９ 倍。随焊后热处理温度升高，ｄａ／ｄｔ 下降， ＫＩＳＣＣ 升高。３０４ 母材的环境断裂受应变产生活性通道机理控制；而焊缝主要受预存活性通道机理制约，以沿晶断裂为主，所需ＫＩＳＣＣ 较低，ｄａ／ｄｔ 较大。在焊缝中，铁素体呈阳极而优先溶解，其数量越多，越易呈半连续或连续的网状，意味着预存活性通道越通畅，环境断裂敏感性越高。焊缝成分和焊后热处理的影响，实际上都是通过改变铁素体的数量和形态而起作用的
Three types of welding electrodes, A002, A132 and A302, and 0C × 6h (600, 800 and 1050) three kinds of post-weld heat treatments were used to study the environmental fracture behavior of different welds in 304 steel. The test is to bend the specimen with a cantilever beam at room temperature. 5mol / LNaCl + 2. 5mol / LH2SO4 solution. The da / dt ~ K1 curves of various welds were measured, and the erosion test, corrosion electrochemical test and fracture analysis were conducted. The results show that the KISCC of weld is 30 ~ 38MPam 1/2, increasing in order of A002, A302 and A132, only increasing from 62% to 79% of the base metal. The crack propagation rate da / dt is about 5 ~ 7 × 10-6 mms-1, 2 for base metal. 8 ~ 3. 9 times. With the post-welding heat treatment temperature, da / dt decreased, KISCC increased. The fracture of 304 base metal is controlled by the active channel mechanism of strain generation. However, the weld is mainly controlled by the mechanism of pre-existing active channels, mainly by intergranular fracture, with lower KISCC and larger da / dt. In the weld, the ferrite anode preferentially dissolved, the greater the number, the more likely to be semi-continuous or continuous mesh, which means that the more pre-activated active channel, the higher the sensitivity of environmental rupture. The composition of the weld and the effect of the post-weld heat treatment actually work by changing the amount and morphology of the ferrite