Hot Corrosion Behavior of Friction Welded AISI 4140 and AISI 304 in K2SO-60% NaCl Mixture

Understanding the behavior of weldment at elevated temperatures and especially the corrosion behavior has become an object of scientific investigation recently. Investigation has been carried out on friction welded AISI 4140 and AISI 304 in molten salt of K2SO4-60% NaCl environment at 550, 600 and 650 degrees C under cyclic condition. The resulted oxide scales in the weldment have been characterized systematically by surface analytical techniques. From the results of the experiments, it is observed that the scale thickness on low alloy steel side was higher than that on stainless steel side. Furthermore, weld interface has been found to be more susceptible to degradation than base metals due to inter diffusion of element across the interface and the formation of intermetallic compound. The influences of welding parameters and the temperature of exposure on the hot corrosion behavior of the weldment were discussed in this paper.