A Study on the Microstructure and Mechanical Properties for the Weldment with Variation of Welding Process of the API 5L-B42 Pipeline for Natural Gas Transmission

천연가스 수송용 API 5L-X42 강관의 용접방법에따른 용접부의 미세조직과 기계적 특성에 관한 연구

Demand of the clean and convenient natural gas has continuously increased with recognizing of the environment problem since liquefied natural gas was introduced in Korea. Clean fuel natural gas was supplied to each city through high tensile strength pipeline connected by welding. Grades of pipeline were divided into the high and middle pressure according to supply pressure. Pipeline was welded mainly SMA welding process due to its easy handling, the other welding process was adopted according to the constructing condition. We were examined on the microstructure variation and mechanical properties of weld metal for high pressure pipeline, API 5L X-42.