摘要作为一种加氮的双相不锈钢。2205 双相不锈钢具有较强的耐腐蚀性，尤其是焊 接的时候耐腐蚀性尤为明显。早期的双相不锈钢可以耐中等强度的均匀腐蚀和氯应力 腐蚀断裂。但是在焊接情况下使用时，其性能就会大大下降。为了改善这种情况，氮 元素就加入了 2205 双相不锈钢，使它的耐腐蚀性能得到提升。81511

实验先对母材及焊缝的金相组织进行了分析，根据母材与不同焊接参数的焊缝的 组织差异分析点蚀性能好坏。然后对试样在 3。5％NaCl 溶液中做电化学实验。进行恒 电压极化下腐蚀电流与温度曲线和不同温度的动电位扫描极化曲线测得，分析得出临 界点蚀温度。结合组织与焊接参数分析点蚀性能。

最后得到结果：2205 双相不锈钢的母材在 3。5%NaCl 溶液中的临界点蚀温度在 60。7℃左右，这比在不同参数下焊接试样的焊接头的临界点蚀温度都要高。不同焊接 参数的焊接试样的临界点蚀温度有 47。5℃，50℃，51℃，45℃，49℃。由于焊接参数 的不同，会使焊缝组织两相比例存在差异，两相比例越接近 1 耐点蚀性能越好。

毕业论文关键词：2205 双相不锈钢；激光复合焊接；临界点蚀温度

Abstract 2205 duplex stainless steel is a kind of duplex stainless steel with nitrogen。 Nitrogen added significantly improves the corrosion resistance of 2205 duplex stainless steel, especially in the case of welding。 Early duplex stainless steel can withstand moderate-intensity uniform corrosion and chloride stress corrosion cracking。 However, when used in welding conditions, the performance will be greatly decreased。 To improve this situation, nitrogen element joins the 2205 duplex stainless steel。 This  not  only increases the corrosion resistance, and the weld ability is very good。

First, this experiment analyzed the microstructure of base metal and weld, analyzed pitting performance according tot he base metal and weld with various welding parameters。 Then letting the sample do electrochemical experiments in 3。5% NaCl solution。 Then, Analyzing results of critical pitting temperature by means of measuring corrosion current and temperature curve under constant voltage polarization and potentiodynamic polarization curves at different temperatures。

Finally, the results showed that, the critical pitting temperature of base metal of 2205 duplex stainless steel in 3。5% NaCl solution is about 60。7 ℃, which are higher than those samples with different welding parameters of the welding head。 The critical pitting temperature of different welding parameters are 47。5℃, 50℃, 51℃, 45℃ and 49℃。  Due

to the different welding parameters, there are differences in weld ratio of two phases, the phase ratio is closer to 100%, the pitting resistance will be better。

Keywords:   2205   duplex   stainless   steel;   laser   hybrid welding;   critical   pitting temperature

目 录

第一章 绪论 1

1。1 前言 1

1。1。1 2205 双相不锈钢简介 1

1。1。2 双相不锈钢的组成分类 1

1。1。3 双相不锈钢的性能 2

1。1。4 双相不锈钢的主要应用领域 3

1。2 双相不锈钢激光复合焊接工艺 4

1。2。1 激光复合焊接分类 5

1。2。2 激光复合焊接优点及应用