mild steel hollow pipe 1) Standard:API 5L,ASTM 36.10M,A106,A53,DIN ... .6) Technique:Hot Rolled,Cold Drawn,Seamless,ERW,LSAW,SSAW,7) Surface treatment:bare,black painting,anti rust oil,hot dipped galvanized,3pe,etc8) Length ... ,chemical,power,shipbuilding,boiler,construction,,metallurgy,etc mild steel hollow pipe