閥門用燒結(jié)閥座的PTFE和RPTFE的美標(biāo)標(biāo)準(zhǔn)號(hào)或國(guó)標(biāo)標(biāo)準(zhǔn)號(hào)？ASTM D4894-07 Standard Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Ram Extrusion Materials. 問：閥門用燒結(jié)閥座的PTFE和RPTFE的美標(biāo)標(biāo)準(zhǔn)號(hào)或國(guó)標(biāo)標(biāo)準(zhǔn)號(hào)？答：ASTM D4894-07 Standard Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Ram Extrusion Materials.聚四氟乙烯