Chulho Cho

Samsung (South Korea)

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Co-Authors

s.w. nam

Samsung (South Korea)

Namhyun Kang

Pusan National University

Eun-Young Jeong

Wonkwang University

Jaeyik Lee

Pohang Iron and Steel (South Korea)

Dajung Lee

Seoul National University

Bongjin Kim

Busan Digital University

Myunghyun Kim

Kyung Hee University

Myeonghwan Choi

Pusan National University

Ji-Hoon Kim

Pusan National University

Kwang-Soo Kim

Korea Aerospace Research Institute

Cooperative Institutions

Pusan National University

Samsung (South Korea)

Hyundai Heavy Industries (South Korea)

Samsung (United States)

Korea Institute of Machinery and Materials

Korea Institute of Materials Science

Korea Institute of Industrial Technology

Portland State University

Korea Electronics Technology Institute

Xinjiang New Energy Research Institute (China)

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Mechanical and Microstructural Behaviors of Gas Tungsten Arc Dissimilar Metal Welds of High-Mn Steel and Stainless Steel 316L Using Various Fillers for Cryogenic Fuel Tanks

Korean Journal of Metals and Materials (2022)

Chulho Cho s.w. nam Sunghoon Yu Myeonghwan Choi Namhyun Kang

The gas tungsten arc (GTA) weldability of high-Mn (HMn) steel and austenitic stainless steel (STS) 316L using dissimilar metal welds (DMWs) was investigated, to fabricate a fuel tank for an LNG-fueled ship. Three types of welding fillers, HMn steel, STS 309LMo and Inconel 625, were applied to the DMWs. The weldability of the DMWs was examined by investigating mechanical properties at 25 and -196 o C, followed by microstructural evolution and weld deformation. The GTA welding process was performed with a heat input range of 0.72–1.89 kJ/mm. All of the fillers employed in the study produced reasonable mechanical properties and low levels of precipitation, such as M7C3 and Fe3C. However, the DN specimen using the Inconel 625 filler exhibited reduced ductility in the bending test. This was attributed to Nb-carbide precipitations at dendrite boundaries at the root weld. The DM specimen using HMn filler experienced severe thermal deformation because it had a relatively higher coefficient of thermal expansion than the other fillers during heating by arc and solidification. Therefore, STS 309LMo and HMn wires were determined to be the appropriate fillers for the DMW of HMn steel and STS 316L for cryogenic applications, and the HMn wire requires attention to weld deformation.

Weldability

Inconel

Ductility (Earth science)

Austenitic stainless steel

10.3365/kjmm.2022.60.9.673

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Citations (5)

A New Study on the Fatigue Properties of SA Weld Joints by Considering the Effects of Welded Bead Shape

Journal of Marine Science and Engineering (2022)

Dongpil Cho s.w. nam Chulho Cho Dajung Lee Eun-Young Jeong

Tandem SAW (Submerged Arc Welding) is one welding process that has been applied to maximize the welding productivity at the panel stage in ship building field. The weld bead profiles produced by Tandem SA welding exceed the acceptance criteria specified in some international regulations, such as AWS D1.1, ISO 5817 and NORSOK M-101. These regulations limit the applicable weld bead profiles, especially weld bead height, regardless of any consideration of design category. The fundamental reason for the limitation of weld bead profiles is related to the weldment fatigue properties. In this regard, we have investigated the effect of weld profiles on fatigue properties. The effect of weld bead profiles on fatigue properties has been experimentally verified and statistically analyzed, and new criteria for weld bead profiles which satisfy E curve as the design S-N curve are proposed for tandem SA welding.

Bead

Fatigue limit

10.3390/jmse10101527

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Citations (3)