国产核电安全端异种金属焊接件的微观结构及局部性能研究

发布时间：2018-04-27 22:13

本文选题：异种金属焊接 + 微观结构　；参考：《金属学报》2017年01期

【摘要】：利用OM、SEM、显微硬度仪、微小试样拉伸实验及慢应变速率拉伸实验对国产带热丝隔离层核电安全端焊接件不同部位的微观结构及局部的力学性能和应力腐蚀敏感性进行了研究。发现,在SA508/52Mb界面处的52Mb中具有大量的对应力腐蚀敏感的I型晶界及II型晶界,导致此界面具有最高的应力腐蚀敏感性;SA508热影响区存在明显的组织过渡;316LN热影响区中随着距熔合线距离的增加,重位点阵(CSL)晶界的数量分数逐渐增大,Σ3晶界与理想的Σ3晶界的偏差角减小,残余应变逐渐减小,残余应变的最高值出现在对接焊底焊位置处的316LN热影响区中,导致316LN的热影响区也具有较高的应力腐蚀敏感性。焊接件不同部位的力学性能存在较大的差异。对于硬度分布而言,显微硬度变化最剧烈的位置在SA508/52Mb界面附近,且此界面附近的52Mb具有最高的硬度,此界面附近的SA508脱C区具有最低的硬度。强度的变化趋势与硬度的变化趋势类似。一般强度高的地方断裂应变低。焊接件不同位置的性能差异主要取决于不同部位的微观结构(包含组织、成分等)差异。
[Abstract]:The microstructure, local mechanical properties and stress corrosion susceptibility of the safety end welds with hot wire insulator were studied by OMSEM, microhardness tester, microspecimen tensile test and slow strain rate tensile test. It is found that there are a large number of type I and II grain boundaries sensitive to stress corrosion in 52Mb at the SA508/52Mb interface. As a result, the interface has the highest sensitivity to stress corrosion in the heat affected zone SA508. There is an obvious microstructure transition in the heat affected zone of 316LN with the increase of the distance from the fusion line. The number fraction of grain boundary increases gradually, the deviation angle between 危 3 grain boundary and ideal 危 3 grain boundary decreases, and the residual strain decreases gradually. The maximum value of residual strain appears in the 316LN heat affected zone at the bottom welding position of butt welding. The heat affected zone of 316LN is also sensitive to stress corrosion. There are great differences in mechanical properties between different parts of welded parts. For the distribution of microhardness, the most drastic change of microhardness is near the SA508/52Mb interface, and the 52Mb near the interface has the highest hardness, and the lowest hardness is found in the SA508 de-C region near the interface. The change trend of strength is similar to that of hardness. Generally, where the strength is high, the fracture strain is low. The properties of welded parts in different positions depend mainly on the microstructure (including microstructure, composition, etc.) of different parts.
【作者单位】：中国科学院金属研究所核用材料与安全评价重点实验室辽宁省核电材料安全与评价技术重点实验室;中国科学院大学;上海核电装备焊接及检测工程技术研究中心;
【基金】：国家自然科学基金项目No.51301183 上海市科委项目No.14DZ2250300 中国科学院前沿科学重点研究项目No.QYZDY-SSW-JSC012~~
【分类号】：TM623;TG457.1

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