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Subject: Re: Stress relieving pressure die castings
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Date: 07/08/01 at 6:18 AM
Posted by: David Pye
In Reply to: Re: Stress relieving pressure die castings posted by pradeep anjaria on 04/14/01 at 5:14 AM:
The problem you are facing is caused by residual machining stresses. If the stresses are not reloieved prior to final heat treatment, then the indused stresses will begin to relieve themselves at the start of the final heat treat procedure. My suggestion to you would be, to strees relieve the tool as cloes as you can, but before the final machining operation before the final heat treastment procedure. Leave yourself some tolerance to account for the movement that will take place and take small finishing cuts for the final machine operation. When you come yto the heat treat operation, make sure that you carefully pre-heat the die. Temeratures for stress relieving can be any temperature. I work on the princip[le that the higher you go in temperature for stress rel;ieving, the more risk you have of scale and decarburization occuring. So I suggest a temp around 900F (485C) and soak at temp for 60 minutes per hour of maximum cross section. Hope that this helps you.
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