Do you need a welding certificate for pp welding?

yes. According to the inquiry of official website, China's Safety and Quality Supervision Bureau, pp welding belongs to the technical welding type of work, and it is necessary to hold a welding practice certificate before taking up the post. Welding, also known as welding, is a manufacturing process and technology to join metals or other thermoplastic materials such as plastics by heating, high temperature or high pressure.