1) CW - continuous weld - a method of producing small diameter pipe (1/2-4")
2) ERW - electric resistance weld - most common form of manufacture for stainless steel pipe in sizes from 2 3/8-22" OD
1 in (inch) = 25.4 mm
1 psi (lb/in2) = 6,894.8 Pa (N/m2) = 6.895x10-2 bar