... Model:201,301,304. 1)stainless steel tube(welded) usded for door,window,guard,rainling etc. 2)Hight polished in both ... pressure test, crystal rot test, heat treatment, NDT Chemical Composition of Material MaterialComposition201202304316430C≤0.15≤0.15≤0.08≤0.08 ... %≥30%≥35%≥35%Hardness (HV)<253<253<200<200 Chinese different types of stainless steel pipe for construction use with competitive price