Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
125 words
Method for the powder metallurgical production of high speed products comprising (a) soft annealing a starting high-speed steel powder in a first annealing step in a non-oxidizing environment (b) mechanically fragmenting the soft annealed powder (c) annealing the fragmented powder in a second annealing step at the austenitic temperature region of the steel in a non-oxidizing environment to improve the compactability of the fragmented powder by reducing its hardness and by forming aggregates of fragmented particles (d) mechanically compacting the second annealed fragmented powder in a die to form a green body of the desired product shape (e) sintering the green body in a non-oxidizing environment until communicating porosity has been eliminated and (f) Subjecting the sintered body to hot isostatic compaction to full density.
Claim 2
Dependent Claim
125 words
Method for the powder metallurgical production of high speed products comprising (a) soft annealing a starting high-speed steel powder in a first annealing step in a non-oxidizing environment (b) mechanically fragmenting the soft annealed powder (c) annealing the fragmented powder in a second annealing step at the austenitic temperature region of the steel in a non-oxidizing environment to improve the compactability of the fragmented powder by reducing its hardness and by forming aggregates of fragmented particles (d) mechanically compacting the second annealed fragmented powder in a die to form a green body of the desired product shape (e) sintering the green body in a non-oxidizing environment until communicating porosity has been eliminated and (f) Subjecting the sintered body to hot isostatic compaction to full density.
Claim 3
Dependent Claim
18 words
Method according according to claim 1, wherein the annealing of the starting powder is carried out in vacuum.
Claim 4
Dependent Claim
29 words
Method according to claim 1, wherein the soft annealed powder is fragmented by wet milling the powder using a milling liquid containing no more than 0.1% H 2 O.
Claim 5
Dependent Claim
15 words
Method according to claim 3, wherein the milling liquid contains at least one organic solvent.
Claim 6
Dependent Claim
20 words
Method according to claim 3, wherein the milling is conducted in a mill which is lined with high speed steel.
Claim 7
Dependent Claim
68 words
Method according to claim 1, wherein the annealing of the fragmented powder is conducted in at least two steps, wherein a first step is at a temperature of between 850° and 950° C., and the second step is at a temperature which is 75°-250° C. lower than the temperature of the first step but for a length of time which is 2-20 times that of the first step.
Claim 8
Dependent Claim
11 words
Method according to claim 1, wherein the fragmented powder is ground.
Claim 9
Dependent Claim
24 words
Method according to claim 1, wherein the powder is compacted to form a green body in a die under a pressure of 300-700 MPa.
Claim 10
Dependent Claim
11 words
Method according to claim 8, wherein said pressure is 400-600 MPa.
Claim 11
Dependent Claim
24 words
Method according to claim 8, wherein a pressing additive is added to the powder before compaction, at a concentration of between 0.1 and 0.5%.
Claim 12
Dependent Claim
28 words
Method according to claim 8, wherein graphite is added to the powder before compaction, at a concentration determined stoichimetrically by the carbon and oxygen content of the powder.
Claim 13
Dependent Claim
19 words
Method according to claim 1, wherein the sintering is conducted at a temperature of between 1150° and 1250° C.
Claim 14
Dependent Claim
14 words
Method according to claim 12, wherein said temperature is between 1180° and 1220° C.