... well roundness and polish 3.small tolerance welded thin wall steel pipe 1.material:201 202 304 316 SUS2.surface:Mirror, ... 7.we can deal with welded joint.Namewelded thin wall steel pipeStandardASTM A554,A312,A249,A269 and A270Material Grade304,316, ... 201,202,316L,430Main Materiala) 201 (Ni0.8%-1%)b) 202 (Ni: 3.5%-4.5%)c) 304 (Ni: ... principle of peace and mutul-benefits. welded thin wall steel pipe