... kinds of finned tubes. 1, finned tube function: heat transfer;2, the fin-tube type: DR (extrusion type), L (winding type), high ... frequency welding;3, fin tube materials: 1, base tube: carbon steel, ... type, high frequency welding), copper (winding type).4, finned tube specifications: 1, base tube: OD16, OD19, OD1 ", OD38; 2, fin: OD34, ...