Method for processing and densifying metal powder

Claim 1

A method for producing a substantially fully dense compact from prealloyed powder metal comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particle to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause extensive brittle fracture of the particles to maintain the integrity of the particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal.

Claim 2

A method for producing a substantially fully dense compact from prealloyed powder metal comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particle to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause extensive brittle fracture of the particles to maintain the integrity of the particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal.

Claim 8

A method for producing a substantially fully dense compact from prealloyed powder metal by hot consolidation wherein the powder metal and resulting compact exhibit a marked increase in hot formability comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particle to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause extensive brittle fracture of the particles to maintain the integrity of the particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal thereby producing a condition of high hot formability in the powder particles during consolidation which is preserved in the resulting compact to facilitate subsequent hot forming.

Claim 9

A method for producing a substantially fully dense compact from prealloyed powder metal by hot consolidation wherein the powder metal and resulting compact exhibit a marked increase in hot formability comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particle to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause extensive brittle fracture of the particles to maintain the integrity of the particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal thereby producing a condition of high hot formability in the powder particles during consolidation which is preserved in the resulting compact to facilitate subsequent hot forming.

Claim 10

A method for producing a substantially fully dense compact from prealloyed powder metal by hot consolidation wherein the powder metal and resulting compact exhibit a marked increase in hot formability comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particles to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause a reduction in the size of a significant number of individual particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal thereby producing a condition of high hot formability in the powder particles during consolidation which is preserved in the resulting compact to facilitate subsequent hot forming.

Claim 11

A method for producing a substantially fully dense compact from prealloyed powder metal by hot consolidation wherein the powder metal and resulting compact exhibit a marked increase in hot formability comprising the steps of a. providing a fully alloyed powder of predetermined composition, b. cold working the particles of the prealloyed powder metal to introduce an amount of strain equivalent to at least about a forty percent reduction in size along a major axis of the particles to thereby lower the recrystallization temperature of the powder metal, said cold working being carried out at an energy level less than that which will cause a reduction in the size of a significant number of individual particles, c. maintaining the powder metal at a temperature below the lowered recrystallization temperature until the powder is to be consolidated and thereafter d. hot consolidating the powder metal by heating the powder metal to a temperature at least slightly above the lowered recrystallization temperature to recrystallize the powder metal, but below that at which excessive grain growth occurs to maintain a relatively small grain size in the compact and by applying pressure to the heated powder metal thereby producing a condition of high hot formability in the powder particles during consolidation which is preserved in the resulting compact to facilitate subsequent hot forming.