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Consolidation of an Iron-base Superalloy by Powder Metallurgy Techniques.
MISSING :22 pages
As part of its goal to minimize the requirements for critical materials, the federal Bureau of Mines has investigated the consolidation of an iron-base superalloy (20 pct cr, 5 pct each ni and mn, 1 pct each c, w, mo, and cb, and the balance fe) and its modifications by powder metallurgy (p/m) techniques. Vacuum- atomized, prealloyed powder was used. Consolidation was by sintering of cold-pressed alloy powder, or by forging plus rolling or extrusion of canned powder. Several commercial lubricants were evaluated in the pressing operation. At 50-tsi compacting pressure with up to 3 wt-pct lubricant, green strengths did not exceed 1,000 psi. Powder sintered just below the solidus temperature attained a tensile strength of 69,000 psi and 4 pct elongation. Liquid-phase sintering produced higher densities, lower tensile strengths, and nil ductibility. Canned powder was forged and rolled at 1,200 deg c, yielding a 100-hr rupture strength of 9,800 psi at 815 deg c and a room-temperature tensile strength of > 130,000 psi at 6 pct elongation. Heat treatment of modified p/m iron-base alloy containing 0.63 pct c resulted in a 100-hr ruptured strength of 17,000 psi. Oxidation resistance at 805 deg to 815 deg c of the forged and rolled p/m iron-base alloy was similar to that of the cast iron-base alloy and superior to conventional stainless steels.
IH; Report of Investigation;
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division