The Effects of Hydrogen on Sulfur in Ferrous Compacts

High hydrogen containing atmospheres, such as endothermic gas and dissociated ammonia, effectively remove much of the sulfur that is added to ferrous compacts for machinability. Sulfur loss was found to decrease with lower hydrogen concentrations in the atmosphere. The high hydrogen sulfide concentrations present with high hydrogen atmospheres will reduce the life expectancy of the metal components in the furnace. Low hydrogen concentrations in the atmosphere produce little hydrogen sulfide and expected belt and muffle life will significantly increase. Additions of water to the sintering atmosphere did not appear to have a significant effect on the sulfur content of the compacts.