ANSI/AWS E308-16 Rutile Electrode : The Effect of Endothermic Materials on Undercut Defect on Low Carbon Stainless Steel

Abstract

This study is the part of a program to obtain the fundamental knowledge on the effect of endothermic materials on the undercut defect of welding, of which information is scarce in international welding literature. Undercut is one of the most crucial problems which decreases the reliability and restricts the many parameter of welding (like welding speed, weaving pattern, etc.). One reason for this type of defect is excessive current, causing the edges of the joint to melt and drain into the weld; this leaves a drain-like impression along the length of the weld. Another reason is if a poor technique is used that does not deposit enough filler metal along the edges of the weld. A third reason is using an incorrect filler metal, because it will create greater temperature gradients between the center of the weld and the edges. Other causes include too small of an electrode angle, a dampened electrode, excessive arc length, and slow speed. The AWS regulations state that the maximum depth of undercut should not exceed 0.25 mm Cerit (Eng Fail Anal 17:571–578, 2010). In this investigation two rutile coated electrodes are taken. One of these is prepared by increasing the amount of calcite and dolomite with subsequent increase in silica and other electrode is of same composition of AWS/ANSI E308-16 rutile electrodes. This modification improves the slag system of electrode and helps in absorbing excess heat generated during the welding process. Undercuts are measured and other operational behavior like welding current, electrode angle, arc length and electrode travel speed of the electrode were kept constant.