Before delivery, ZOZEN gas-fired fire tube boiler shell is covered with the stainless steel film to prevent damage to the boiler shell in the process of transportation and installation. The film will be removed after installation. The mirror stainless steel shell of the boiler has the features of low heat loss and beautiful appearance. The pictures show the blank pressing process of the stainless steel materials, which is the previous process of installing the stainless steel film, this process aims to make the material seam much flatter and firmer where surfaces intersect and meet.