Wear-resistant shaped magnetic article and process for making the same
AssigneeCarpenter Technology Corporation
InventorFriedrich W. Ackermann
Life of this patent
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Abstract
Shaped magnetic articles made from powder material are provided containing about 70 to 85% nickel, more than 10% iron, one or more of 0 to 5% chromium, 0 to 6% molybdenum, 0 to 6% copper, 0 to 2% manganese, 0 to 1% titanium and 0 to 1% niobium, containing also about 0.1 to 2.0% of a refractory metal oxide, and having a unique combination of magnetic and physical properties. A process for making the shaped magnetic articles from metal powder and refractory oxide is also disclosed by which the metal and refractory oxide powder are blended, sintered and worked to provide substantially homogeneous articles having at least 99% theoretical density.
Claims29
A ferromagnetically soft wear-resistant shaped article made from metal powder in which a refractory oxide powder is substantially uniformly dispersed therein having a minimum particle size greater than about 1 micron which is large compared to the Block wall thickness in the composition of said article, the composition of said article consisting essentially of about
- ______________________________________ Weight Percent ______________________________________ Carbon <0.025 Manganese 0-2 Nickel 70-85 Chromium 0-5 Molybdenum 0-6 Copper 0-6 Titanium 0-1 Niobium 0-1 Refractory oxide 0.1-2.0 ______________________________________
- the balance being essentially iron and incidental impurities with the iron content being greater than 10%, said article having a density at least 99% of theoretical with residual voids being larger than the Block wall thickness.
A process for making a ferromagnetically soft wear-resistant shaped article which includes the steps of blending metal powder and a refractory oxide powder having a minimum particle size greater than about 1 micron that is large compared to the Bloch wall thickness in the composition of said article to provide a substantially homogeneous mixture in such proportions that the composition of the article in its sintered and densified condition in weight percent consists essentially of about
- ______________________________________ Weight Percent ______________________________________ Carbon <0.025 Manganese 0-2 Nickel 70-85 Chromium 0-5 Molybdenum 0-6 Copper 0-6 Titanium 0-1 Niobium 0-1 Refractory oxide 0.1-2.0 ______________________________________
- the balance being essentially iron and incidental impurities with the iron content being greater than 10%, then forming a preliminary shape from the blended powders, sintering the preliminary shape at a high enough temperature and for a long enough time in a reducing or inert atmosphere to provide a substantial amount of densification without reducing or melting the refractory oxide, and then working the sintered shape and reducing the thickness thereof to provide a shaped article having at least 99% theoretical density and in which the metal elements present except that combined to form refractory oxide are fully alloyed and homogeneously distributed.
Dependencies are inferred from the claim text.