저합금강의 인코넬 625 육성용접 후 열처리에 따른 미세조직 및 기계적 특성

• Published in: 대한금속·재료학회지, 54(8) Vol. 54; no. 8; pp. 585 - 591
• Main Authors: 김승필, Seung Pil Kim, 장재호, Jae Ho Jang, 김정수, Jung Soo Kim, 김병준, Byung Jun Kim, 손근용, Keun Yong Sohn, 남대근, Dae-geun Nam
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 05.08.2016; 대한금속·재료학회
• Subjects: double heat treatment; hardness test; metals; microstructure; welding; 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2016.54.8.585

Overlay welding technique is one of methods used to improve metal mechanical properties such as strength, toughness and corrosion resistance. Generally, Inconel 625 alloy is used for overlay welding layer on low carbon steels for economic consideration. However, the method produces some problems in the microstructure of the cast structure and some defects, caused by the elevated temperatures of the overlay welding process. To resolve these problems, heat treatments are required. In this study, Inconel 625 alloy was welded on a low carbon steel by the overlay welding process to investigate the resulting microstructure and mechanical properties. A double heat treatment was performed to improve the mechanical properties of the welding and substrate layers. It was found that Inconel 625 alloy had an austenite microstructure after the first heat treatment, but the low carbon steel had a ferrite-pearlite microstructure after the second heat treatment. After the double heat treatment, the sample showed the optimum hardness because of grain refinement and homogenization of the microstructure. (Received October 23, 2015; Accepted February 29, 2016)