Purpose

Duplex stainless steel is composed of equal amounts of austenite and ferrite, which has excellent corrosion resistance and strength. However, after the metal was welded, the ratio of austenite and ferrite in the joint is unbalanced, and secondary phase precipitates are produced, which is also an important cause of pitting corrosion in the joint.

Design/methodology/approach

This paper aims to study the mechanical and corrosion behavior of welded joints, by adjusting the welding parameters of laser hybrid welding, dual heat sources are used to weld 2205 duplex stainless steel. The two-phase content of different parts of the welded joint is measured to study the influence of the ratio of the two-phase on the mechanical and corrosion properties of the joint.

Findings

The ratio of austenite and ferrite in different welded joints has an obvious difference, and from top to bottom, the austenite content decreased gradually, and the ferrite content increased gradually. The harmful phases are precipitated in the middle and lower part of the joint. The strength of welded joints is slightly lower than that of base metal. At the same time, the fracture analysis shows that some ferrite phases are affected by the precipitate in the grain and produce quasi-cleavage fracture. The corrosion results show that the corrosion resistance of the welded joints is lower than that of the base metal, and the concentration of chloride ions affects the corrosion resistance.

Originality/value

In this paper, the authors use the influence of different welding processes on the two-phase ratio of the joint to further study the influence of the microstructure on the corrosion resistance and mechanical properties of the weld.

中文翻译：

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2205双相不锈钢激光复合焊接接头力学及腐蚀行为研究

目的

双相不锈钢由等量的奥氏体和铁素体组成，具有优良的耐腐蚀性和强度。但是，金属焊接后，接头中奥氏体和铁素体的比例不平衡，产生二次相析出，这也是接头点蚀的重要原因。

设计/方法/方法

本文旨在研究焊接接头的力学和腐蚀行为，通过调整激光复合焊接的焊接参数，采用双热源焊接2205双相不锈钢。测量焊接接头不同部位的两相含量，研究两相比例对接头力学性能和腐蚀性能的影响。

发现

不同焊接接头中奥氏体与铁素体的比例有明显差异，自上而下，奥氏体含量逐渐减少，铁素体含量逐渐增加。有害相在接头的中下部析出。焊接接头的强度略低于母材。同时断口分析表明，部分铁素体相受晶粒中析出物的影响而产生准解理断裂。腐蚀结果表明，焊接接头的耐腐蚀性能低于母材，氯离子浓度影响耐腐蚀性能。

原创性/价值

在本文中，作者利用不同焊接工艺对接头两相比的影响，进一步研究了显微组织对焊缝耐蚀性和力学性能的影响。