Product Code: ICA11_1605

Characteristics of Microstructures and Mechanical Properties of Laser Welded API X-100 Steel for Line Pipe
Authors:
Mok-Young Lee, Advanced Metallic Materials Research Team, RIST; Pohang South Korea
Hyun-Byung Chai, Technical Research Laboratories, POSCO; Pohang South Korea
Presented at ICALEO 2011

The strength of materials for pipe line becomes higher, because that is increase the capacity of transportation such as oil or gas. The performance of those welds was decreased by increasing of alloy contents added to increase the strength. In this study, high strength API X-100 steel was welded with 10kW fiber laser on bead-on-plate. The process parameters such as laser output power, travel speed and focal position were changed to increase weld quality. To investigate the weld defects or bead shape, the cross sectional views were observed with optical microscope. Also it was welded with laser on I-butt joint with milled edge. The weld was evaluated with microstructure, hardness and mechanical test. From the results, the absorbed energy on Charpys impact test at -30 was achieved 30~90J and 50~110J on weld metal and heat affected zone separately.