Heat treating to meet a specific hardness range 2

[contactspecialist]

I'm looking for some feedback on heat treating material to meet a given micro hardness range.
Am I okay to heat treat the same piece of material as many times as needed to get within a targeted hardness range or does the reintroduction to heat change the material in a way that would impact other performance propterties besides hardness. for example if I am testing each time to still be sure my Tensile and elongation still pass for a given Temper So at the end of the day I have a piece of material that passes both hardness, Tensile and Elongation but it has been heat treated 3 times instead of once.

Thank in advance for all the feedback.
Regards,
contact Specialist

 

[forging82]

Depending on the heat treat you will impact your other mechanical properties(tensile, elongation). What material are you working with and what properties are you trying to achieve?

 

[arunmrao]

Please specify the material and the hardness range that you need to understand your requirements.Also multiple heat treatment is undesirable and 3 times might just be the limit for acceptance,provided, the grain size, scaling, dimensions have not affected the part.

 

[contactspecialist]

Primary alloy make up: Pd 35%; Ag 30%; Pt 10%; Au 10%.
Arunmrao - along the lines of your response. When I test for tensile, elongation, and hardness for a specified temper all test are passing, but I have heat treated it 3 or more times. My concern; is there a degradation in the alloy that may not be reflected in the listed test results after seeing heat (3 or more times) i.e. grain size, scaling that may not be visible upon inspection using the naked eye.

 

[arunmrao]

contactspecialist,
Sorry ,I have no clue about the material. I am sure the heat treatment will be done under vacuum . Issue like scaling, is not possible ,It is better, I do not stick out my neck any more .

 

[Maui]

What was the heat treat process that was used (step by step with details) to harden this alloy? What also matters is the application in which this material will be used. What is the application? And what specifically are the property requirements for it that the material must satisfy?

Maui

http://www.EngineeringMetallurgy.com

 

[mrfailure]

This looks like an age hardened alloy. My concern would be the amount of residual stress you placed on it even if you had performed stress relief treatments after each heat treatment. This can eventually lead to cracking.

 

[tbuelna]

contactspecialist- I did a quick check to see if I could find any data on the alloy composition you described, but I didn't find much. As far as I can tell your material seems to be a heat-treatable alloy, and is used mostly for high-performance electrical contact applications. The only published standard I found for similar materials was ASTM B540, but I don't have a copy, so I can't say if it contains anything helpful.

Hope that helps.
Terry