Chung-Yun Kang

Effects of laser power on hardness and microstructure of the surface melting hardened SKD61 hot die steel using Yb:YAG disk laser

Effects of laser power on hardness and microstructure of the surface melting hardened SKD61 hot die steel using Yb:YAG disk laser Kwang-Hyeon Lee*, Seong-Won Choi** and Chung-Yun Kang**,† *Busan Laser Application Support Center, Korea Institute of Machinery & Materials, Busan 618-230, Korea **Dept. of Material Science and Engineering, Pusan National University, Busan 609-735, Korea †Corresponding author : kangcy@pusan.ac.kr (Received April 14, 2015 ; Accepted June 10, 2015)

Effect of Tensile Properties and Microstructure on the Heat Input of Ni-Doped High Manganese Welding Wire

The cryogenic high manganese steel is designed for tanks that transport liquefied natural gas, which has increased in demand globally. For this purpose, high manganese steel weld wire with ni added for Flux Cored Wire welding was welded under various heat input conditions. Then, a tensile test was measured to evaluate the mechanical properties. As a result, the heat input condition satisfying the required yield strength was 1.5 kJ. The reason for this phenomenon is that a small amount of Cu contained in the base metal and the welding rod is generated in grain boundaries of Cu2O during solidification, causing liquefaction cracking.