... for R&D, it can be made by material of copper, copper alloy, carbon, aluminum, titanium or double material mixed A) Our ... fin tube, base material is carbon steel SA179, or stainless steel SA213, or Copper DHP, or copper nickel alloy C70600, C71500, C70400 ... Economizer fin tube, in material of carbon steel SA179, or stainless steel SA213, or Copper DHP, or copper nickel alloy C70600, C71500, C70400 ...