HDG steel pipe 1. many different sizes of the products 2..low and ... ,DIN 1629,1626,BS,JIS.etc2) Material: ASTM A106/A53,ST37,35, API 5L GR. B /X42/X52.etc3) Size: OD 1/8”to ... :petroleum,gas,chemical,power,shipbuilding,boiler,construction,,metallurgy,etc HDG steel pipe