| 摘要 |
<p>A method of making sintered powder metal parts which particularly includes a hot forging step, is disclosed. Selected powders of a predetermined particle size distribution, are blended and agglomerated by cold compaction into a preform. The preform or briquette is then coated with a thin shell of a chemically inactive radiation absorbing material, preferably graphite, under ambient conditions. The coated briquette is then sintered in a continuous through-put furnace with the temperature maintained at a level of at least 2000.degree.F and the part being subjected to the furnace heating for a period of 5-30 minutes. The sintered part may then be subjected to direct hot forging with the retained temperature of sintering utilizing the graphite coating as a die lubricant, or the sintered part may be cooled and then subsequently reheated for hot forging, again utilizing the retained graphite coating as a die lubricant. If hot forging is not to be employed, the graphite particles are removed such as by brushing so that sizing, machining or grinding may be carried out without the presence of the graphite coating.</p> |
