ISO flanges are made from Argon Oxygen Decarburization (AOD) 304 stainless steel. This material is certified to meet ASTM-240 and has less than 0.01% sulfur in order to prevent sulfur stringers. Grain size is 3 to 6 per ASTM E-112.
Maximum inclusion size is 2.5 per ASTM E-45. Normally our standard material is in the low carbon range for 304 stainless steel. For increased corrosion resistance, some sizes are available from stock in 316L stainless steel.
Optional fastener and nonrotatable ISO flanges are available from stock for 2-1/2 to 20 inch tube sizes. Both use a Viton O-ring, held in place by a centering ring, to effect a seal with a vacuum range of 10-8 Torr. ISO components can be baked to 204÷C.
ISO flanges can also be used with standard clamps and aluminum seals to obtain a UHV seal bakeable to 150÷C.