Sintered coining process
AssigneeStackpole Limited
InventorsPeter Jones, Roger Lawcock
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Abstract
A process of coining sintered articles of powder metal comprising: blending carbon, ferro manganese, and lubricant with compressible elemental iron powder, pressing the blended mixture to form the articles, high temperature sintering of the articles in a reducing atmosphere and then coining the sintered articles to final shape so as to narrow the tolerance variability of coined articles and substantially eliminate secondary operations.
Claims17
A coining process for blending, sintering, and coining powder metal articles, that coining process comprising:
- blending carbon, ferro manganese and lubricant with compressible iron powder to form a blended mixture;
- pressing said blended mixture to form said articles;
- sintering said articles in a reducing atmosphere at a temperature of at least 1250.degree.C.;
- and
- coining said sintered articles to a final shape.
A process of precision coining a sintered article of powder metal comprising:
- (a) selecting iron powder;
- (b) determining the desired properties of said sintered article and selecting:
- (i) a quantity of carbon;
- and
- (ii) a quantity of ferro manganese to produce an article having a composition of between 0.3% to 2.0% manganese, 0.2% to 0.85% carbon with the remainder being iron and unavoidable impurities;
- (c) grinding separately said ferro manganese to a mean particle size of approximately 8 to 12 microns and substantially all of said ferro manganese having a particle size of less than 25 microns;
- (d) introducing a lubricant while blending said carbon, and ferro manganese with said iron powder;
- (e) pressing said mixture to form said article;
- (f) sintering said article at a temperature between 1,250.degree. C. and 1,350.degree. C. in a vacuum or reducing atmosphere of 90% blended nitrogen and 10% hydrogen to produce said sintered article of powdered metal;
- (g) coining said sintered article to a final shape to narrow the dimensional tolerance variability of coined articles and substantially eliminate secondary operations.
A process of gas quenching coined articles of powder metal, that process comprising:
- blending carbon, ferro manganese, ferro molybdenum, ferro chromium and lubricant with compressible iron powder;
- pressing said blended mixture to form said articles;
- sintering said articles at a temperature in the range of 1250.degree. C. to 1350.degree. C. in a reducing atmosphere;
- coining said articles to a final form:
- and gas quenching said article.
Dependencies are inferred from the claim text.