The Effects of Welding Wires on the Weldabilities of API X-100 with Laser-Arc Hybrid Welidng

Kim, Sungwook; Lee, MOK-Young

doi:2014.32.5.437

J Weld Join > Volume 32(5); 2014 > Article

Special Issue

Journal of Welding and Joining 2014;32(5):437-442.
DOI: https://doi.org/10.5781/JWJ.2014.32.5.7 Published online October 30, 2014.

The Effects of Welding Wires on the Weldabilities of API X-100 with Laser-Arc Hybrid Welidng

Sungwook Kim^*, MOK-Young Lee^*

Correspondence: Sungwook Kim,
Email: sungwook@rist.re.kr

Abstract

In this study, API-X100 steel pipes were welded with various kinds of welding wires in the laser-arc hybrid welding process. 10kW fiber laser source was combined to MIG arc welding process. API X-100 steel of base metal was of 16.9mm thickness, and butt welding applied. After welding, full penetration weld was acquired by 1-pass welding. A root porosity and the lack of fusion was observed in some welding conditions. By the mixing the melted wire, acicular ferrite, polygonal ferrite, pro-eutectoid, aligned side plate, and bainite structures were observed at the weld metal. From the observation of hybrid weld, unmixed zone had more Ni and Cr. The unmixed zone was a 1/3 area of the weld metal. As the mechanical test of the hybrid welding, tensile test and impact test applied. From the tensile test, all of the welding except SM70S was fractured at the base metal. The result of the impact test at -30 degree C led 60J~320J of the absorbed energy. The result of the low-absorbed energy might be from the coarse equiaxed structures of the weld metal.

Key Words: API X-100 pipe, Laser-arc hybrid welding, Fiber laser, Filler wire