In recent years, stringent environmental regulations for air pollution have led to increased demand for liquefied natural gas (LNG). Therefore, the demand for the design and construction of LNG-fueled vessels has also increased. One of the most important points for the design of LNG-fueled vessels is the structural integrity of the LNG fuel tank, particularly at cryogenic temperatures. Low temperature materials are used in the construction of LNG fuel tanks to ensure structural safety. Among the various low temperature materials, nickel steel is commonly employed for the design of LNG storage tanks. In addition, Shielded Metal Arc Welding (SMAW) and Submerged Arc Welding (SAW) are commonly applied to the construction of LNG storage tanks. On the other hand, the application of Flux Cored Arc Welding (FCAW) for nickel steel as an alternative to SMAW and SAW appears to be necessary, considering the high productivity. Nevertheless, there have been few studies of the fracture behavior of nickel steel with FACW compared to SMAW and SAW processes. This study examined the fracture characteristics of 9% nickel steel and weldments considering application for the LNG storage tanks. The fracture characteristics of FCAW was compared with SMAW at 25°C and − 163°C temperatures. As the result, the mechanical properties with FCAW were higher than those with SMAW at 25°C and − 163°C. In addition, SMAW is slightly better than FCAW in terms of the impact absorbed energy. Moreover, the crack tip opening displacement (CTOD) values of the weld metal and heat affected zone (HAZ) with FCAW were higher than those with SMAW.

中文翻译：

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焊接工艺和耗材对 9 Wt.% 镍钢断裂行为的影响

近年来，针对空气污染的严格环境法规导致对液化天然气 (LNG) 的需求增加。因此，对LNG燃料船的设计和建造的需求也有所增加。LNG 燃料船舶设计的最重要点之一是 LNG 燃料箱的结构完整性，尤其是在低温下。LNG燃料罐的建造采用低温材料，以确保结构安全。在各种低温材料中，镍钢通常用于设计 LNG 储罐。此外，保护金属电弧焊（SMAW）和埋弧焊（SAW）通常应用于LNG储罐的建造。另一方面，考虑到高生产率，在镍钢上应用药芯电弧焊 (FCAW) 作为 SMAW 和 SAW 的替代品似乎是必要的。然而，与 SMAW 和 SAW 工艺相比，很少有关于 FACW 镍钢断裂行为的研究。本研究考察了 9% 镍钢和焊接件的断裂特性，考虑应用于 LNG 储罐。FCAW 的断裂特性与 SMAW 在 25°C 和 -163°C 温度下进行了比较。因此，在 25°C 和 − 163°C 时，FCAW 的机械性能高于 SMAW。另外，在冲击吸收能量方面，SMAW略好于FCAW。此外，FCAW 焊接金属和热影响区 (HAZ) 的裂纹尖端张开位移 (CTOD) 值高于 SMAW。