Sim Bernard-Maxmillan, Tang Sai-Hong, Alrifaey Moath, Tchan Jong Edwin-Nyon
Faculty of Engineering, University Putra Malaysia, Serdang 43400, Malaysia.
Department of Mechanical Engineering, Faculty of Engineering Technology and Built Environment, UCSI University, Taman Connaught, Kuala Lumpur 56000, Malaysia.
Materials (Basel). 2022 Mar 1;15(5):1833. doi: 10.3390/ma15051833.
Duplex stainless steel (DSS) has a reasonably high resistance to chloride stress corrosion cracking for offshore and marine applications. However, DSS weld overlay has not been successfully demonstrated due to some inherent problems in achieving pitting and crevice corrosion resistance. In this research work, isothermal heat treatments (350, 650 and 1050 °C) with and different cooling rates have been performed DMR249 Grade A by using shield metal arc welding (SMAW) with an E2209 electrode. Micrographs have shown two phase microstructures of the DSS weld metal, the amounts of austenite phase increased with increment of post-weld heat treatment (PWHT) temperatures. The dilution has maintained consistent values except solution annealing that has shown the disappearance of the heat affected zone in micrographs. The weld metal hardness values increased with PWHT temperatures and remained low at solid solution annealing temperatures. The major alloying elements (C, Mo, Cr, Ni, N, and Fe) were analyzed, as these elements can contribute to intermetallic phases. The results showed that C and Cr content slightly increased with PWHT except for solid solution annealing, Mo showed consistently low content due to dilution effects. Ni maintained higher content, although the heat-treated samples showed slight fluctuations. Nitrogen produced consistent values, as recommended to prevent critical involvement in nitride precipitation.
双相不锈钢（DSS）对于海上和海洋应用具有相当高的抗氯化物应力腐蚀开裂性能。然而，由于在实现点蚀和缝隙腐蚀抗性方面存在一些固有问题，DSS堆焊层尚未得到成功验证。在本研究工作中，采用E2209焊条通过手工电弧焊（SMAW）对DMR249 A级进行了不同冷却速率下的等温热处理（350、650和1050°C）。显微照片显示了DSS焊缝金属的两相微观结构，奥氏体相的含量随着焊后热处理（PWHT）温度的升高而增加。除固溶退火外，稀释率保持一致，固溶退火在显微照片中显示出热影响区的消失。焊缝金属硬度值随PWHT温度升高而增加，在固溶退火温度下保持较低水平。对主要合金元素（C、Mo、Cr、Ni、N和Fe）进行了分析，因为这些元素会促成金属间相。结果表明，除固溶退火外，C和Cr含量随PWHT略有增加，由于稀释效应，Mo含量始终较低。Ni含量保持较高，尽管热处理后的样品略有波动。氮产生一致的值，这是为防止关键参与氮化物沉淀所推荐的。
