carbon steel pipe material: Q195,Q215,Q235,Q345,20#,30#,45# etc standard: GB/T6728-2002 or ASTM A500 We export main products include Square Stainless Steel Pipe,Stainless Steel Pipe,seamless stainless steel pipes,welded Stainless Steel Pipe and so on .carbon steel pipe: 1) Material: Q195,Q215,Q235,Q345,20#,30#,45# and so on . 2) Standard: GB/T6728-2002 or ASTM A500 or EN10219.or other materials ...