Powder metallurgy forging

Claim 2

IN THE PROCESS OF STEEL POWDER MELTALLURGY HOT FORGING, THE IMPROVEMENT OF OBTAINING A LOWER FLOW STRESS DURING FORGING WHICH COMPRISES HOT FORGING LOW ALLOY STEEL POWDER AT A TEMPERATURE IN WHICH THE STEEL POWDER IS CHARACTERIZED BY A MICROSTRUCTURE CONSISTING ESSENTIALLY OF FERRITE AND AUSTENITE, EACH OF THESE PHASES BEING PRESENT IN A VOLUME PERCENTAGE OF

Claim 3

A process in accordance with claim 1 in which the ferrite and austenite are both present in a volume percentage of at least 10 percent and their respective grain sizes are at least ASTM 10.

Claim 4

A process in accordance with claim 1 in which the ferrite and austenite are both present in a volume percentage of at least about 20 percent and their respective grain sizes are ASTM 12 or finer.

Claim 5

A process in accordance with claim 1 in which the ferrite is at least 60 percent by volume.

Claim 6

A process in accordance with claim 1 in which the alloy steel powder forged is of a composition consisting of about 0.05 to 0.15 percent carbon, about 0.8 to 2.5 percent silicon, up to 2 percent manganese, about 0.5 to 4 percent nickel, about 0.2 to 2 percent molybdenum, up to about 0.2 percent columbium, up to 2 percent copper, about 0.01 to 0.25 percent oxygen, the balance being essentially iron, the particles forming the powder being of irregular shape and further characterized by a particle size of not greater than about 500 microns, a grain size not less than an average ASTM grain size of about 10 and with their outer surfaces being substantially enveloped by an oxide film not greater than about 10 microns in thickness.

Claim 7

A process in accordance with claim 5 in which the oxygen contents of the alloy steel does not exceed about 0.15 percent, the particle size is less than 275 microns and the oxide film is not greater than about 5 microns.

Claim 8

A process in accordance with claim 5 in which the alloy composition contains copper in an amount sufficient to impart significant hardening and strength upon being cooled from an aging treatment of 900*F.-1000*F.

Claim 9

A process in accordance with claim 5 in which the alloy contains at least 1 percent copper, at least 0.01 percent columbium and in which the molybdenum does not exceed 1.2 percent.

Claim 10

A process in accordance with claim 1 in which the alloy steel contains from 0.8 to 1.5 percent silicon, up to 1 percent manganese, about 0.5 to 1.2 percent nickel and about 0.2 to 0.5 percent molybdenum.

Claim 11

A process in accordance with claim 9 in which the alloy steel contains from about 1 to 2 percent copper.

Claim 12

A process in accordance with claim 1 in which the alloy steel contains from 2 to 2.5 percent silicon, about 2 to 3 percent nickel, about 0.8 to 1.2 percent molybdenum and about 1 to 2 percent copper.

Claim 13

A process in accordance with claim 1 in which the alloy steel contains up to 0.4 percent carbon, about 0.8 to 2.5 percent silicon, up to 2 percent manganese, about 0.5 to 4 percent nickel, about 0.2 to 2 percent molybdenum, up to 0.2 percent columbium, up to 2 percent copper, oxygen present in an amount not greater than 1, up to 3 percent each of cobalt, chromium, tungsten, vanadium, up to 0.5 percent in total of aluminum plus titanium and the balance essentially iron.

Claim 14

A process in accordance with claim 2 in which the alloy steel powder forged is of a composition consisting of about 0.05 to 0.15 percent carbon, about 0.8 to 2.5 percent silicon, up to 2 percent manganese, about 0.5 to 4 percent nickel, about 0.2 to 2 percent molybdenum, up to about 0.2 percent columbium, up to 2 percent copper, about 0.01 to 0.25 percent oxygen, the balance being essentially iron, the particles forming the powder being of irregular shape and further characterized by a particle size of not greater than about 500 microns, a grain size not less than an average ASTM grain size of about 10 and with their outer surfaces being substantially enveloped by an oxide film not greater than about 10 microns in thickness.

Claim 15

A process in accordance with claim 2 in which the alloy steel powder contains up to 0.4 percent carbon, about 0.8 to 2.5 percent silicon, up to 2 percent manganese, about 0.5 to 4 percent nickel, about 0.2 to 2 percent molybdenum, up to 0.2 percent columbium, up to 2 percent copper, oxygen present in an amount not greater than 1, up to 3 percent each of cobalt, chromium, tungsten, vanadium, up to 0.5 percent in total of aluminum plus and the balance essentially iron.

Claim 16

A process in accordance with claim 3 in which the alloy steel powder contains up to 0.4 percent carbon, about 0.8 to 2.5 percent silicon, up to 2 percent manganese, about 0.5 to 4 percent nickel, about 0.2 to 2 percent molybdenum, up to 0.2 percent columbium, up to 2 percent copper, oxygen present in an amount not greater than 1 percent, up to 3 percent each of cobalt, chromium, tungsten, vanadium, up to 0.5 percent in total of aluminum plus titanium and the balance essentially iron.