... seamless steel tubes for ASTM A333, GR.A, GR.1, GR. 6 grade: A, GR.7, GR.3, specifications:1/ ... 7the German standard DIN2448 /1629 seamless steel tubes, steel grade: St37, St44, St52, specifications: 1/ 4" - ... heat pipe) DIN17175-1979: carbon structural steel, steel grade St35.8-St45.8/ I, St35.8-St45. ... 1-70mm 11 Low and medium pressure boiler pipe steel grade GB3087-1999, 10, 20: # #, specifications: 6 ...