Description
Postalloy 540-MCG is an iron base alloy designed for the buildup and overlay of gray cast iron components, typically Class 20 to Class 50. Postalloy 540-MCG is most often used to rebuild worn components back to original size, or as an underlayment prior to putting a harder more wear resistant alloy on top of. If you are repairing broken or cracked components, it is advisable to use a high nickel alloy, such as Postalloy 53-SPL (wire) or Postalloy 50 (electrode). The hardness of Postalloy 540-MCG is influenced by the amount of weld mixed with the base metal and the cooling rate of the weld. It is advisable to use a low preheat to avoid thermal shocking the base metal, at least 150ºF. When welding on gray iron a preheat of 150ºF-200ºF will produce a hardness in the range of 300BHN to 400BHN. If a preheat of 300ºF-500ºF is used, the hardness will range between 200BHN to 300BHN, it is advisable to weld with low amperage and voltage settings to reduce weld dilution.