439 steel is made of ordinary ferrite material (430) as raw material. By reducing the C content and adding stable elements such as Ti, the resistance to intergranular corrosion, formability, and weldability of the steel are improved. Compared with 304 steel, although the elongation is lower (about 30%), the strength and corrosion resistance are similar, and the corrosion resistance is better than that of 200 series materials. The demand for 439 stainless steel coil plates in industries such as elevators, escalator decorative panels, building decorative panels, structural pipes, automotive exhaust system components, and washing machine barrels will increase year by year.