Process for sintering powder metal parts

Claim 1

In a process for sintering powder metal parts comprising: (a) passing the parts through a furnace adapted therefor from its upstream end to its downstream end, said furnace having two successive zones, an upstream zone, which is maintained at a temperature in the range of about 800° F. to about 2200° F. and a cooling zone, said furnace further having an atmosphere therein comprising carbon monoxide, hydrogen, carbon dioxide, water and nitrogen distributed throughout the zones; (b) permitting the parts to reside in the upsteam zone for a sufficient length of time to cause sintering; and (c) removing the sintered parts from the furnace, the improvement comprising: introducing a mixture consisting essentially of methanol and nitrogen into the upstream zone at a point where a temperature of at least about 1500° F. is maintained, the methanol and nitrogen being in a ratio sufficient to provide, when subjected to such temperature, an atmosphere comprising, in percent by volume, about 1 to about 20 percent carbon monoxide; about 1 to about 40 percent hydrogen; and balance nitrogen.