morsetaper2
Diamond
- Joined
- Jul 2, 2002
- Location
- Gaithersburg, MD USA
My coworker has some questions about stress releiving aluminum. Neither of us are very knowlegable about the subject, so I thought I might ask here and learn something. Below is the situation. Can anyone confirm, or offer advice, or point us to a source for some further information.
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I have a part where a large amount of aluminum is hogged out in rough machining, the part is then stress relieved, then the final machining is performed. By hogging out all this material roughly. Then performing a stress releive. then go back and perform final machining, we are trying to prevent the part from turing into a "potato chip".
I called out AMS 2770E stress relieve on the drawing, but the machine shop came back and said they thought the temperatures listed in the spec were too high.
They said that typically 6061-T6 is treated at about 177C (350F) for stress relieve. But the spec called for a temp at about 341C (645F). Soak for 2 hours min for .5 inch thickness (add .5 hour for every addl .5 inch part thickness. And then air cool.
Is there some science or metallurgical basis for the lower temperatures suggested by the shop? I tend to believe the shop, but I want to know what the lower temp stress relieve is based on.
*******************
I have a part where a large amount of aluminum is hogged out in rough machining, the part is then stress relieved, then the final machining is performed. By hogging out all this material roughly. Then performing a stress releive. then go back and perform final machining, we are trying to prevent the part from turing into a "potato chip".
I called out AMS 2770E stress relieve on the drawing, but the machine shop came back and said they thought the temperatures listed in the spec were too high.
They said that typically 6061-T6 is treated at about 177C (350F) for stress relieve. But the spec called for a temp at about 341C (645F). Soak for 2 hours min for .5 inch thickness (add .5 hour for every addl .5 inch part thickness. And then air cool.
Is there some science or metallurgical basis for the lower temperatures suggested by the shop? I tend to believe the shop, but I want to know what the lower temp stress relieve is based on.