Conductor Pipe Casing Welding in Onshore Drilling Rig: Shield Metal Arc Welding

Abstract

This study aims to analyze the effect of dissimilar welding, especially between the temporary wellhead and the heat-affected zone (HAZ) of the conductor pipe casing. This type of research is an experimental research design comparing mechanical properties and microstructure changes between specimens. The primary materials in this research are a conductor pipe casing (API 5CT Grade K55) with a diameter of 20 inches, a temporary wellhead (AISI 4130), and a welding rod (AWS A5.1 E7016) with a size of 3.2 mm x 400 mm. This study used five specimens determined based on passing the non-destructive test (NDT) of magnetic particle inspection (MPI). Prior to the splicing test, each specimen was heated at 250⁰C. Test the connection on each specimen using shield metal arc welding (SMAW). Each specimen will undergo a joint test with a different number of welds. In this case, the first specimen undergoes a joint test with one welding, and so on until the fifth specimen undergoes a joint test with five repetitions of welding. The results of the HAZ conductor pipe casing connection will be assessed based on metallography macro-micro, chemical composition, and hardness. The results showed that the number of temporary wellhead welding on the HAZ conductor pipe casing was significantly affected. In this case, the HAZ conductor pipe casing becomes wide, and the microstructure shrinks. In addition, carbon equivalent (Ceq) and hardness have increased.