Deformation prediction of porcelain-enameled steels with strain history by press forming and high-temperature behavior of coating layer

Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection, resistance to heat and abrasion, high hardness, hygiene and ease of cleaning. The typical process to produce enameled steels is roughly divided into two stages: the first stage consists of a forming process to give the desired shape to a steel substrate, and the second stage consists of a firing process to bond enamel frits on the substrate. This firing process requires a high temperature above 800 °C, which may lead to austenitic transformation and severe thermal deformation of the steel substrate. The aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process, including firing. The FE analysis involves analyzing the strain history of the steel substrate, which comprises the stress and thickness distributions of the substrate and its deformed shape, and the high-temperature behavior of the enamel coating layer. The validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the substrate. The results reveal that the FE analysis results agree well with the experimental results with 8% error.