Purpose

The purpose of this study is to examine the effects of sensitization on the metallurgical characteristics of weld joints made up of austenitic stainless steel (AISI 316L) and ferritic stainless steel (AISI 430), using the gas tungsten arc welding (GTAW) process with ER316L filler wires.

Design/methodology/approach

A non-consumable tungsten electrode with a diameter of 1.6 mm was used during the GTAW procedure. The filler wire, ER316L, was selected based on the recommendation provided in literature. To explore the interconnections among the structure and properties of these weldments, the techniques including scanning electron microscopy and optical analysis have been used. In addition, the sensitization behaviour of the weldments was investigated using the double loop electrochemical potentio-kinetic reactivation (DLEPR) test.

Findings

Microstructural analyses revealed the occurrences of coarsened grains with equiaxed columnar grains and migrating grain boundaries in the weld zone. The results of the DLEPR test demonstrated that heat affected zone (HAZ) of AISI 430 was more susceptible to sensitization than HAZ of AISI 316L. Microstructure analysis also revealed the precipitation of large amounts of chromium carbide at the grain boundaries region of AISI 430 welded steel, causing more sensitization and, as a result, more failure or breaking at the side of AISI 430 weld in the dissimilar weldment of AISI 316L–AISI 430.

Originality/value

The present work has been carried out to determine the appropriate welding conditions for joining AISI 316L and AISI 430, as well as the metallurgical properties of the dissimilar weldment formed between AISI 316L and AISI 430. Owing to the difficulties in measuring the performance of these types of dissimilar joints given their unique mechanical and microstructural characteristics, research on the subject is limited.

中文翻译：

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敏化对奥氏体-铁素体不锈钢异种焊接冶金性能影响的研究

目的

本研究的目的是检查敏化对奥氏体不锈钢 (AISI 316L) 和铁素体不锈钢 (AISI 430) 焊接接头冶金特性的影响，采用 ER316L 气体保护钨极电弧焊 (GTAW) 工艺填充线。

设计/方法论/途径

GTAW 过程中使用直径为 1.6 mm 的非消耗性钨电极。填充焊丝 ER316L 是根据文献中提供的建议选择的。为了探索这些焊件的结构和性能之间的相互关系，使用了扫描电子显微镜和光学分析等技术。此外，还使用双环电化学动电位再激活（DLEPR）测试研究了焊件的敏化行为。

发现

显微组织分析表明，焊缝区出现粗化晶粒、等轴柱状晶和迁移晶界。DLEPR 测试结果表明，AISI 430 的热影响区 (HAZ) 比 AISI 316L 的 HAZ 更容易敏化。微观结构分析还表明，在 AISI 430 焊接钢的晶界区域析出大量碳化铬，导致更多的敏化，从而导致 AISI 316L 异种焊件中 AISI 430 焊缝侧面发生更多失效或断裂。 –AISI 430。

原创性/价值

目前的工作是确定连接 AISI 316L 和 AISI 430 的适当焊接条件，以及 AISI 316L 和 AISI 430 之间形成的异种焊件的冶金性能。由于测量这些类型的性能存在困难。鉴于异种接头独特的机械和微观结构特征，该主题的研究是有限的。