Shielded metal arc welding of AISI 409M ferritic stainless steel: study on mechanical, intergranular corrosion properties and microstructure analysis

Abstract

Purpose The purpose of this study is on AISI 409 M ferritic stainless steel (FSS) which is developing a preferred choice for railway carriages, storage tanks and reactors in chemical plants. The intergranular corrosion behavior of welded SS 409 M has been studied in H2SO4 solution (0.5 M) with the addition of NH4SCN (0.01 M) with different heat input. As this study is very important in context of various chemical and petrochemical industries. Design/methodology/approach The microstructure, mechanical properties and intergranular corrosion properties of AISI 409 M FSS using shielded metal arc welding were investigated. Shielded metal arc welding with different welding current values are used to change the heat input in the joints resulted in the microstructural variations. The microstructure of the welded steel was carefully inspected along the width of the heat-affected zone (HAZ) and the transverse-section of the thin plate. Findings The width of heat affected zone (3.1,4.2 and 5.8 mm) increases on increasing the welding heat input. Due to change in grain size (grain coarsening) as HAZ increased. From the microstructure, it was observed that the large grain growth which is dendritic and the structure become finer to increase in welding heat input. For lower heat input, the maximum microhardness value (388HV) was observed compared with medium (351 HV) and higher heat input (344 HV), which is caused by a rapid cooling rate and the depleted area of chromium (Cr) and nickel (Ni). The increase in weld heat input decreases tensile strength, i.e. 465 MPa, 440 MPa and 418 MPa for low, medium and high heat input, respectively. This is because of grain coarsening and chromium carbide precipitation in sensitized zone and wider HAZ. The degree of sensitization increases (27.04%, 31.86% and 36.08%) to increase welding heat input because of chromium carbide deposition at the grain boundaries. The results revealed that the higher degree of sensitization and the difference in intergranular corrosion behavior under high heat input are related to the grain growth in the HAZ and the weld zone. Originality/value The study is based on intergranular corrosion behavior of welded SS 409 M in H2SO4 solution (0.5 M) with the addition of NH4SCN (0.01 M) with different heat input which is rarely found in literature.

Recent findings on corrosion of ferritic stainless steel weldments: A review

“…The propensity for the occurrence of intergranular corrosion increased with heat input. [38] 409M FSS SMAW -DL-EPR H2SO4 (0.5 M) with the addition of NH4SCN (0.01 M)…”

“…The intergranular corrosion attack on FSS (AISI 430) weldments were aggravated by the Cu-CuSO 4 with 50 % H 2 SO 4 corrosive solution [37]. Ambade et al [38] studied the influence of welding heat input on the corrosion behaviour of 409M FSS weldment. It is observed that the width of HAZ increased with heat input.…”

“… Studies have attributed the reduction in corrosion resistance of FSS weldment to the increase in the heat input during welding [33,38] while according to Gupta et al [41], the opposite trend is true. There is limited knowledge concerning the optimum heat input values or range of values to produce excellent corrosion-resistant FSS welded joints for different grades of FSSs.…”

Investigation of corrosion inhibition of 4-(4-nitrophenyl) thiazol-2-amine on the copper in HCl: experimental and theoretical studies

“…There are different types of corrosion and different factors such as metal type, corrosive environment, different welding processes, which affect the corrosion of metals and their alloys. Many studies have been done in this field (Ambade, et al , 2021; Tembhurkar et al , 2021; Ambade et al , 2021).…”