ASTM A270 specification covers grades of seamless, welded, and heavily cold worked welded austenitic and ferritic/austenitic stainless steel sanitary tubing intended for use in the dairy and food industry and having special surface finishes.
ASTM A270’s emphasis is on the surface finish of tubing, which can be specified in a number of ways to a number of different finishes. Polish tubing meets or exceeds the 3-A standards with an ID polish of a 20 Ra on the Inside of the Tube and a 150 Grit or 32 Ra on the Outside of the tube.
Welded sanitary stainless steel tubing is manufactured using automatic TIG welding technology, all the tubing detected by Eddy current test, weld ends corner cut at 90 degrees to the tube length for automatic welding, tubes thoroughly rinsed with de-ionized water with no residue, bright annealed with 99.99 percent hydrogen gas at the minimum temperature level of 1040 degrees C and rapidly quenched to achieve the maximum cold-finish effect.
