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A Design Study in Steel - Crossbleed Valve for the F-5

Heat Treating and Machining

Heat treatment and machining of the valve body is a coordinated process. 

Per the AMS specification,  the valve body is heat treated in a combined heat-treat / machining process.

1.  Two-part heat treat -- 

  • Homogenize in air at 2100 F for at least 90 minutes and cool to 70F.

  • Solution heat treat (HT) in air at 1925F for 30-60 minutes and air cool to 70F. 

2.  In the solution HT condition, the casting is machined for mating surfaces, screw holes, and the center channel, as shown in the picture to the right.

In the annealed condition, 17-4PH has good machinability, similar to that of 304 stainless steel.

3.   After machining, the valve body is precipitation heat treated to develop the desired microstructure, strength, and hardness at 896°F (480°C) for 90 minutes with air cooling.


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Copyright 2007 by the Steel Founders' Society of America.
All rights reserved.  Address comments to: 
blairr@sfsa.org
Last Modified:December, 2007 by STG

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