... the ASTM A 554 and others.Features:1) Material of stainless steel: grade: AISI 201, 304 4302) Applied field: construction upholstery, and ... ,19,20,22,23,28,29, 31.8 ,35,36,38,45, 47,48,50.8,60,63,76,88.9 ... be manufactured according to customers' requirements AISI 201 304 430 stainless steel series round/ square /Rectangular tube/pipes