The new standard HG/T20538-2016 for steel lined tetrafluorocarbon steel pipe and steel lined tetrafluorocarbon pipe fittings is a chemical industry standard. Loose lined tetrafluorocarbon pipe or steel lined tetrafluorocarbon pipe is a tetrafluorocarbon lining method that directly puts the lined tetrafluorocarbon pipe into the steel pipe, and the flange sealing surfaces at both ends are out of the flanging of the tetrafluorocarbon pipe. Tight lined tetrafluorocarbon steel pipe is compounded by mechanical method, and there is no gap between the lined tetrafluorocarbon pipe and the steel pipe. The tetrafluorocarbon container is rolled, Rolling lining tetrafluoro tank is a method of fusing and adhering F40 powder to the steel body, and lining tetrafluoro layer with a certain peel strength. Molded tetrafluoro pipe is a method of lining tetrafluoro with steel pipe and pipe fittings as the external mold of steel, evenly filling the tetrafluoro paste solid between the inner cavity and mold core of steel pipe and pipe fittings, applying a certain pressure to compact the tetrafluoro, and then sintering. The pipe fittings are generally molded PTFE pipes. PTFE lined pipes, PTFE lined pipe fittings, PTFE lined elbows, PTFE lined tees, PTFE lined reducers.