THE INFLUENCE OF DIFFUSIBLE HYDROGEN IN WELD METAL AND MOISTURE CONTENT LEVELS IN FLUX RELATED WITH WELD METAL MECHANICAL PROPERTIES IN SUBMERGED ARC WELDING PROCESS FOR LINE PIPE MANUFACTURING

摘要

The mechanical properties of welding material is correlative with the diffusible hydrogen content in weld metal and level of moisture content in flux. Minitab16program to predict mechanical properties correlated to diffusible hydrogen content in weld metal and level of moisture content in flux, such as yield strength, tensile strength, elongation and average Charpy impact toughness of welding material is established by using submerged arc welding process in line pipe manufacturing. The present paper aims to experiment and investigate the line pipe SAW Flux used for offshore/onshore applications. Flux moisture content has been studied under Karl Fischer Coulometer method. Subsequently, flux was then used to make weld to analysis for 'diffusible hydrogen content in weld metal' through mercury displacement method. This detailed study envisages and explains the correlations between the mechanical properties and micro structures of weldments. Evaluating the variance of moisture level in flux and diffusible hydrogen content in weld metal proves the advantage of restricting the moisture content along with good practices to accomplish better weld quality.