Hi-density forming process

DETAILED DESCRIPTION OF THE INVENTION A method of making a sintered powdered metal article having high density and ductility with improved mechanical properties is herein described.
The present invention employs low carbon steel compositions that, after sintering, may be formed to high density at ambient temperature.
The carbon utilized herein has a composition of less than 0.
5% and preferably less than 0.
3% by weight of the final sintered article.
The compositions of the powdered metal articles that are the subject of this invention are of the kind not generally employed in the powdered metal industry.
Prior art compositions generally included the use of alloys consisting of iron, carbon, copper, nickel and molybdenum.
In this invention, alloys of iron, such as manganese, chromium and molybdenum are used and are added as ferro alloys to the base iron powder as described in U.
S.
Pat.
No.
5,476,632, which is incorporated hereby by reference.
Carbon is also added.
The alloying elements ferro manganese, ferro chromium, and ferro molybdenum may be used individually with the base iron powder, or in any combination, such as may be required to achieve the desired functional requirements of the manufactured article.
In other words two ferro alloys can be used or three ferro alloys can be blended with the base iron powder.
Examples of such base iron powder includes Hoeganaes Ancorsteel 1000/1000B/1000C, Quebec Powder Metal sold under the trade marks QMP Atomet 29 and Atomet 1001.
The base iron powder composition consists of commercially available substantially pure iron powder which preferably contains less than 1% by weight unavoidable impurities.
Additions of alloying elements are made to achieve the desired properties of the final article.
Examples of compositional ranges of alloying elements that may typically be used include at least one of the following: 0 to 0.
5% carbon, 0 to 1.
5% of manganese, 0 to 1.
5% chromium and 0 to 1.
5% of molybdenum where the % refers to the percentage weight of the alloying element to the total weight of the sintered product and the total weight of the alloying elements is between 0 to 2