TO STUDY THE EFFECT OF DIFFERENT WELD WIRE ALLOYING ON METALLURGICAL AND MECHANICAL PROPERTIES OF MULTI ARC SAW WELDED HSLA LONGITUDINAL LINE PIPES

摘要

The current scenario of HSLA line pipe welded with critical parameters by Automatic Submerged Arc Welding being widely used in critical services for both onshore & offshore, also challenging to achieve stringent mechanical properties i.e low temperature toughness, hardness, YS/TS ratio, etc. Recent studies proved that the Ti-B wires been widely used to weld line pipes which gives higher fracture toughness values at lower temperature. In this experiment, an attempt has been made to maintain the volume fraction of acicular ferrite by alloying elements in weld metal with variation of low to high heat input range. The purpose of this experiment is to determine the effect of different alloyed wire with respect to critical welding parameters on mechanical & Metallurgical properties. This investigation also includes metallographic changes, role of different alloying elements for improving the microstructure and distribution of inclusions in weld metal, which directly affects the mechanical properties of weld metal. Based on the results, Optimization has been done which is focusing on welding consumables from the existing chemistry to find at what extent the variation of chemistry causes undesired metallurgical changes in the weld metal and also how it influences the mechanical properties of welded line pipe.