Powder processing method
A powder processing method includes degassing a metallic powder in a rotating chamber that is evacuated to a sub-atmospheric pressure. The method may also include storing the metallic powder in a rotating storage chamber that is pressurized to a super-atmospheric pressure with a dry cover gas.
1. A powder processing method comprising:
degassing a metallic powder in a chamber that is evacuated to a sub-atmospheric pressure;
agitating the chamber that is evacuated to a sub-atmospheric pressure; and
after the degassing, storing the metallic powder in a storage chamber that is pressurized to a super-atmospheric pressure with a dry cover gas.
2. The powder processing method as recited in claim 1 , wherein the degassing includes agitating the metallic powder using baffles within the rotating chamber.
3. The powder processing method as recited in claim 1 , including conducting the degassing at a temperature of 300-800° F.
4. The powder processing method as recited in claim 1 , including conducting the degassing at a temperature of 350-600° F.
5. The powder processing method as recited in claim 1 , including conducting the degassing in a first phase at a first temperature followed by a second phase at a second, greater temperature.
6. The powder processing method as recited in claim 5 , wherein the first temperature is 300-600° F. and the second temperature is 600-800° F.
7. The powder processing method as recited in claim 1 , further comprising agitating the storage chamber.
8. The powder processing method as recited in claim 1 , further comprising rotating the storage chamber.
9. A powder processing method comprising:
degassing a metallic powder in a rotating chamber that is evacuated to a sub-atmospheric pressure; and
prior to the degassing, forming the metallic powder at super-atmospheric pressure and containing the metallic powder in a catch chamber at the super-atmospheric pressure.
10. The powder processing method as recited in claim 9 , including maintaining the catch chamber at a dew point less than −85° F.
11. The powder processing method as recited in claim 9 , including monitoring a dew point in the catch chamber.
12. The powder processing method as recited in claim 9 , further comprising, after the forming, classifying the metallic powder under super-atmospheric pressure with a dew point of less than −85° F.
13. A powder processing method comprising:
storing a metallic powder in a rotating chamber that is pressurized to a super-atmospheric pressure with a dry cover gas; and
purging moist cover gas from the rotating chamber after a predetermined amount of time and replenishing the rotating chamber with new dry cover gas.
14. The powder processing method as recited in claim 13 , wherein the storing includes agitating the metallic powder using baffles within the rotating chamber.
15. The powder processing method as recited in claim 13 , including conducting the storing under a temperature of 65-90° F.
16. The powder processing method as recited in claim 13 , further comprising establishing a continuous flow of the dry cover gas through the rotating chamber.
17. The powder processing method as recited in claim 16 , further comprising maintaining a continuous moisture concentration gradient between the metallic powder and the dry cover gas.
18. The powder processing method as recited in claim 13 , including revolving the rotating chamber at a rate of approximately 0.1-1 revolutions per minute.
19. The powder processing method as recited in claim 13 , including establishing a dew point of less than −90° F. within the rotating chamber.
20. The powder processing method as recited in claim 13 , including pressurizing the chamber using a pressurized gas system having a pressurized gas tank.
21. The powder processing method as recited in claim 13 , including monitoring a dew point in the chamber.
22. A powder processing method comprising:
degassing a metallic powder in a rotating chamber that is evacuated to a sub-atmospheric pressure; and
after the degassing, storing the metallic powder in a rotating storage chamber that is pressurized to a super-atmospheric pressure with a dry cover gas.
23. A powder processing method comprising:
storing a metallic powder in a rotating chamber that is pressurized to a super-atmospheric pressure with a dry cover gas;
purging moist cover gas from the rotating chamber after a predetermined amount of time and replenishing the rotating chamber with new dry cover gas; and
monitoring a level of the dry cover gas in the chamber and, in response to the level, replenishing the dry cover gas in the chamber to maintain a desired pressure.