The carbon steel materials we use are: st35, st35.8, st37, st37.4, st45,st52, st52.4, etc The manufacturing standards we use are: din2391, din73000.din10305-1 din2440, din2448 AstmA106, GrB API 5L, Astm A53 etc Ranges: Outdiameter :6--60,Wall thickness :0.8--6mm