SS316L VIM-VAR MELTED Material is for ultrpurity applications. Hastelloy® C-22 or cobalt-based superalloy (UNS R30003) materials can offer high strength and corrosion resistance. Optimal design, long service life. Optimal design, long service life. here is no spring inside. The valve seat and the diaphragm are integrally welded together. The inner surface roughness can reach Ra 5um, and the flow channels are completely accessible for cleaning.