Failure investigation of welded 430 stainless steel plates for conveyor belts

• Published in: Engineering failure analysis 2020-10, Vol.116, p.104754, Article 104754
• Main Authors: Khattak, M.A., Zaman, S., Kazi, S., Ahmed, H., Habib, H.M., Ali, H.M., Tamin, M.N.
• Format: Article
• Language: English
• Subjects: AISI 430; Failure analysis; Ferritic stainless steel; Intergranular stress corrosion cracking; Sensitization; Welding
• ISSN: 1350-6307; 1873-1961
• DOI: 10.1016/j.engfailanal.2020.104754

•Failure investigation was conducted on butt welded belt (copper billet casting processes) that suffered from cracking•The belt is made of AISI 430 Ferritic stainless steel.•The investigation revealed that the butt weld were in sound conditions, namely no evidences of lack of weld penetration and voids or porosities.•The failure of weld joint was concluded to be due to susceptibility to IGSCC in the presence of high temperature water•The IGSCC was found to be due to depletion of chromium content along the grain boundaries resulting from the formation of chromium carbides and untampered martensites•AISI 430 ferritic stainless steel have low weldability in term of grain growth at HAZ, sensitization and brittleness. Failure investigation considering the material aspects, was conducted on butt welded conveyor belt used in copper billet casting processes, that suffered from cracking. The belt is made of AISI 430 ferritic stainless steel. The results of the investigation indicate that the butt welded joint is in sound condition, without any evidence on the lack of weld penetration, and no void or porosity is found. Thus, the welding procedures are not suspected to be the cause of the failure. The cracking of the welded joint initiated at the grain boundaries in the heat-affected zone (HAZ) and propagated along the weld line and across the welded joint. The failure mode is concluded to be the intergranular stress corrosion cracking (IGSCC), and accelerated by the presence of high temperature and humid environment.