This review article presents an overview of the dissimilar welded joint's microstructure and mechanical behavior. Dissimilar metal weldings are generally employed in high-pressure tubing/tubing-coupler assembly generally functional in subsea oil-gas production instruments and a wide range of geothermal plants and piping systems for subsea manifolds. Thus, dissimilar metal welding has an essential role in enhancing the subsea oil-gas drilling system's structural integrity. Dual-phase super duplex stainless steel 2507 (super DSS 2507) comprises a balanced phase of austenite and ferrite, establishing great attention of manufacturers and researchers due to its mechanical strength and corrosion resistance properties in several hostile surroundings like marine, offshore, petrochemical, and nuclear power plant. The other most frequently used material in the marine application is nitronic steel (N50), primarily used in subsea oil and gas developments in tube and couplers for its corrosion resistance, high strength, and resistance to galling. Nickel-based superalloy Inconel 625 has significant application in the aviation, petrochemical, and marine industry due to its high tensile, yield, and creep strength with excellent corrosion properties in an unfavorable environment. The dissimilar joining of these materials is repeatedly required in marine and offshore industries. This review focuses on the significant difficulties related to the dissimilar welding of super DSS 2507 with nitronic steel (N50) and Inconel 625. Unlike chemical composition, metallurgical properties, mechanical and physical properties of these steel and nickel alloys lead to the problem like stress corrosion cracking, hydrogen embrittlement, ductility dip cracking and migration of carbon. The other metallurgical problems are deleterious secondary phase formation, carbon diffusion-related problem, δ-ferrite phase present in the fusion zone, and residual stresses are required to be removed or decrease their intensity for the qualification of the weld. The effect of intermetallic phases such as sigma phase, FCC carbides like (M₂₃C₆, M₆C, and M₇C₃), laves phase, R and χ-phase, Z-phase on the mechanical property of dissimilar welded joints of each material are reviewed in detail. After the extensive literature review, proper selection of filler metal has also been covered in this article because it plays an essential role in decreasing some of the dissimilar welded joint problems. Heterogeneity across the weldment, unmixed zone formation including peninsula, island, beaches, and filler deficient region, grain boundaries related problems during the dissimilar welded joint of these materials is also discussed thoroughly in this article. The effect of residual stresses in the dissimilar welded joint's distinct condition has also been discussed in detail.

这篇综述文章概述了异种焊接接头的微观结构和机械性能。异种金属焊接通常用于高压油管/油管耦合器组件，通常在海底油气生产仪器和用于海底歧管的各种地热设备和管道系统中发挥作用。因此，异种金属焊接在增强海底油气钻井系统的结构完整性方面具有重要作用。双相超级双相不锈钢 2507 (super DSS 2507) 包含奥氏体和铁素体的平衡相，由于其在海洋、近海、石化和石油化工等多种恶劣环境中的机械强度和耐腐蚀性能，引起制造商和研究人员的极大关注。核电站。船舶应用中另一种最常用的材料是硝基钢 (N50)，由于其耐腐蚀、高强度和耐磨损，主要用于海底石油和天然气开发的管道和接头。镍基高温合金 Inconel 625 具有较高的拉伸强度、屈服强度和蠕变强度以及在不利环境下具有优异的腐蚀性能，因此在航空、石化和海洋工业中具有重要应用。在海洋和近海工业中反复需要这些材料的不同连接。本综述重点关注与超级 DSS 2507 与硝基钢 (N50) 和 Inconel 625 异种焊接相关的重大困难。这些钢和镍合金的机械和物理性能会导致应力腐蚀开裂、氢脆、延展性浸裂和碳迁移等问题。其他冶金问题是有害的二次相形成、碳扩散相关问题、熔合区中存在的 δ-铁素体相，以及需要去除残余应力或降低其强度以进行焊接鉴定。σ相、FCC碳化物等金属间相的影响（M 要求去除残余应力或降低其强度以进行焊缝鉴定。σ相、FCC碳化物等金属间相的影响（M 要求去除残余应力或降低其强度以进行焊缝鉴定。σ相、FCC碳化物等金属间相的影响（M₂₃ C ₆、M ₆ C 和 M ₇ C ₃)、laves相、R相和χ相、Z相对每种材料异种焊接接头力学性能的影响。After the extensive literature review, proper selection of filler metal has also been covered in this article because it plays an essential role in decreasing some of the dissimilar welded joint problems. 本文还深入讨论了焊件的异质性、包括半岛、岛屿、海滩和填料缺乏区域在内的非混合区的形成，以及这些材料异种焊接接头过程中的晶界相关问题。还详细讨论了异种焊接接头不同条件下残余应力的影响。