论文部分内容阅读
通过显微组织分析、硬度测试、极化曲线和扫描Kelvin探针技术,研究了900 MPa级高强钢气保焊焊接接头各区的组织与性能。结果表明:高强钢焊接接头焊缝区、重熔区、回火热影响区、正火热影响区和母材区的组织分别为下贝氏体、马氏体、回火索氏体、细晶珠光体和索氏体。焊接接头不同区域硬度有较大的差异,焊缝区硬度最高,母材区硬度最低,热影响区和熔合区内硬度发生突变;零电流电位Ei=0由相对更正至更负的顺序依次为:焊缝区、母材、重熔区和热影响区,扫描Kelvin探针测量结果表明焊缝区电子逸出功明显高于热影响区,两区域伏打电位相差在100 m V左右。在腐蚀介质中,焊接接头不同区域可形成一个多电极系统,其中,热影响区和重熔区将成为复杂多电极系统中的阳极,最先被腐蚀。
The microstructure, microstructure, hardness, polarization curve and scanning Kelvin probe technique were used to study the microstructure and properties of 900 MPa high strength steel brazing welded joints. The results show that the microstructure of weld zone, remelting zone, tempering heat affected zone, normalizing heat affected zone and base metal of high strength steel welded joint are bainite, martensite, tempered sorbite, fine grained pearlite Body and sorbite. The hardness of weld zone is greatly different in different regions, the hardness of the weld zone is the highest, the hardness of the base material zone is the lowest, and the hardness changes in the heat affected zone and the fusion zone. The sequence of zero current potential Ei = 0 from the relative correction to the negative is : Weld zone, base metal, remelting zone and heat affected zone. The results of scanning Kelvin probe show that the work function of electron in weld zone is obviously higher than that of heat affected zone, and the difference of volt-ampere potential in the two zones is about 100 mV. In corrosive media, different regions of the weld joint can form a multi-electrode system in which the heat-affected zone and the remelt zone will become the anodes in a complex multi-electrode system, the first to be eroded.