Process for the production of sinter iron materials

Abstract

Abstract A powder-metallurgical composition particularly suitable for the production of sleeve valves and valve seats consists of iron containing graphite and .nickel.0.5 - 5% .lead.1 - 4% while molybdenum and cobalt may also be present, the former being present in the range 1.2 - 1.8%, and the content of cobalt being eight times that of molybdenum. Vanadium may also be present within the range 0.05 - 0.2%. After briquetting the compact is sintered and hot or cold pressed at a pressure greater than that used during briquetting, and may then be heated to a temperature above the Ac 3 point, cooled rapidly, and tempered at up to 650 DEG C. Alternatively the heat treatment may be carried out after sintering and prior to cold working. As exemplified, a particular powder composition was briquetted at 3.5 tons/sq. cm, and sintered at 1100 DEG C. in a neutral atmosphere for three hours; the compacts were then heated to 830 DEG C. for fifteen minutes, rapidly cooled, and tempered at 580 DEG C. for thirty minutes, after which they were cold compressed at 7 tons/sq.in.

Inventors

• 👤 Max Koehler

Bibliographic Details