These are ASA 4.25 /ANSI 1 blank flanges, with an O-ring groove, are not bored, and are not rotatable. These CNC lathe turned ASA/ANSI flanges are not bored out for tubing. Both sides of the flange are smooth. They are often used to cover ASA/ANSI ports. ASA/ANSI flanges always mate an O-ring grooved flange with a smooth (non-grooved) flange to form a sealed connection with through-hole bolts, nuts, and washers. These flanges are made of 304 stainless steel.

Dimensions, in. (mm):
A = 4.25 in.(108)
B = 3.125 in. (79.4)
C = 0.50 in. (12.7)
D = 0.625 in. (15.8), 4 Holes
E = 1.87 in. (47.5)

Other Specifications

• Made of 304 Stainless Steel
• Has 4 Bolt Holes
• Bolt Hole Diameter of 0.625 inches (15.8 mm)
• Grooved Flange
• Non-Rotatable Flange
• Non-Bored Flange

ASA flanges are available with a smooth or grooved face, rotatable or non-rotatable, bored or non-bored, and are named for the outer diameter of the flange, from 4.25 to 19 inches. The ANSI name for the same flange size corresponds to the nominal tubing size that can be welded to it, and ranges from 1 to 12 inches in diameter.

ASA / ANSI flanges were originally used for steam pipes but have now been adapted to vacuum. Diffusion pumps, roots blowers, cryopumps and large rotary piston pumps are some examples of vacuum pumps where these flanges are used. When sealed together with O-rings made of Viton, Buna or Silicone, they are capable of achieving vacuum pressures as low as 1x10^-8 Torr. We have a complete line of ASA flanges, O-rings, and bolt sets to fit your most demanding needs.