MUMBAI, India, Sept. 14 -- Intellectual Property India has published a patent application (202641107157 A) filed by Hindustan Institute Of Technology And Science on September 07, 2026, for Method For Enhancing Hot Corrosion Resistance Of 304hcu Stainless Steel Under Molten Salt Environment..
Inventors include K Bharath; A Naga Manoj Kumar; K Hari Gopi Chandu; and Santosh Rajan T.
The application for the patent was published on September 11, 2026, under issue no. 37/2026.
Abstract: The present invention relates to a method for improving the hot corrosion resistance of welded 304HCu stainless steel exposed to aggressive molten salt environments at elevated temperatures. The method involves coating parent and welded 304HCu stainless steel specimens with a molten salt mixture comprising 25 wt.% sodium sulfate (Na2SO4) and 75 wt.% sodium chloride (NaCl) and subjecting the coated specimens to cyclic thermal exposure at approximately 750°C under Type II hot corrosion conditions. Each thermal cycle consists of 5 hours of heating followed by 45 minutes of atmospheric cooling for a total exposure duration of approximately 100 hours. The corrosion behaviour is evaluated through mass gain analysis, oxidation kinetics, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Experimental results indicate that welded specimens exhibit higher corrosion kinetics and cumulative mass gain of approximately 435 mg cm-2 compared to approximately 382 mg cm-2 for parent specimens after 100 hours of exposure, primarily due to chromium depletion, sulfur penetration, chlorine-assisted oxidation, and oxide scale instability. The invention further incorporates surface stabilization techniques including mechanical polishing, oxide pre-conditioning, shot peening, diffusion treatment, ceramic-based coating deposition, and alloy surface modification to enhance chromium-rich oxide scale stability and reduce corrosion-induced degradation. The proposed method improves oxidation resistance, reduces oxide scale cracking and localized corrosion attack, and enhances the operational durability and service life of welded stainless-steel components used in boilers, heat exchangers, thermal power plants, and petrochemical systems operating under high-temperature corrosive environments.
Disclaimer: Curated by HT Syndication.
