Effects of post-weld heat treatments on the microstructure, mechanical and corrosion properties of gas metal arc welded 304 stainless steel

Abstract

Purpose The purpose of this study is to determine the effects of post-annealing and post-tempering processes on the microstructure, mechanical properties and corrosion resistance of the AISI 304 stainless steel gas metal arc weldment. Design/methodology/approach Gas metal arc welding of AISI 304 stainless steel was carried out at an optimized processing condition. Thereafter, post-annealing and post-tempering processes were performed on the weldment. The microstructure, mechanical and electrochemical corrosion properties of the post-weld heat treated samples, as compared with the as-welded, were investigated. Findings The as-welded joint was characterized with sub-granular grain structure, martensite formation and Cr-rich carbides precipitates. This made it harder than the post-annealed and post-tempered joints. Because of slower cooling in the furnace, the post-annealed joint contained Cr-rich carbides precipitates. However, the microstructure of the post-tempered joint is more refined and significantly devoid of the carbide precipitates. Post-tempering process improved the elongation (∼23%), tensile (∼10%) and impact (∼31%) strengths of the gas metal arc AISI 304 stainless steel weldment, while post-annealing process improved the elongation (∼20%) and impact strength (∼72%). Owing to the refined grain structure and significant elimination of the Cr-rich carbide precipitates at the joint, the post-tempered joint exhibited better corrosion resistance in 3.5 Wt.% NaCl solution than the post-annealed and the as-welded joints. Originality/value The appropriate post-weld heat treatment that enhances microstructural homogeneity and quality of the AISI 304 gas metal arc welded joint was determined.

Review of post-processing methods for high-quality wire arc additive manufacturing

“…Sensors can also be used to monitor temperature in various regions, measure the size and shape of beads, evaluate weld pool characteristics, monitor the acoustic signal of deposition, detect electrical conductivity fluctuations, and measure oxygen levels during WAAM. Unlike in fusion-based welding where established process parameters are held constant for producing quality welds [84][85][86], building components via WAAM often requires careful modification of process parameters because of the variances in heat behaviour throughout component manufacturing [6,79]. Weld pool photographs give a wealth of information about the quality of the process.…”

Corrosion resistance of surface-conditioned 301 and 304 stainless steels by salt spray test

“…Compared to the treated samples, the untreated sample experienced more corrosion attack. Several factors could influence the corrosion rate and consequently the weight loss after salt spray test including the extent of deformation, degree of exposure to heat treatment or corrosive environment [22][23][24]. As obvious in Figure 7, the corrosion of test samples seems to be severer in the edges, which may indicate that the processing quality of sample edges has a significant effect on corrosion and might affect the weight loss result.…”

Corrosion Resistance, Evaluation Methods, and Surface Treatments of Stainless Steels

“…Even though they exhibit good corrosion resistance, efforts have continually been made to further improve the corrosion resistance behaviour of stainless steels. Heat treatment such as annealing due to the oxidation of steel surface [4][5][6], surface mechanical treatment [7][8][9][10][11][12], coatings/electrodepositions [13][14][15][16], alloying, machining/molding [17] and many more are presently in use to further improve the corrosion resistance behaviour of stainless steels. Other protection methods include epoxy coating, cathodic protection, and thicker concrete cover.…”