Heat treatment of 17-4PH separately cast specimens

[absaul02]

Hi,

I'm currently making a development about 17-4PH investment casting but I have some doubts about separately cast specimens for tensile and impact tests. Can I heat treated these specimens (diameter of 6.35 mm) in the same charge of pieces of castings? or do i need heat treated the separately cast specimens in different charge? The pieces of casting have a thickness of 2 1/2 inches and a weight of 35 kg.

another question is do i need using an atmosphere such as vacuum, argon or nitrogen? or Can i use a furnace without controlled atmosphere for this material?

Regards.

 

[mfgenggear]

OP
it depends, if it is finished surface or if there is stock removal, for machining.
even if not required follow the AMS 2759/3
procedures. finished surface in a Vacuum, or inert atmosphere. prevent oxidation. precipitation harden. run with specimens for testing.

 

[EdStainless]

We used to do both.
HT some samples in the lab and some with the parts.
Served to verify both the material and the HT.
And nitrogen is not an inert atmosphere.
The alloy will absorb some at the annealing temp and it mess with the phase balance.

 

[absaul02]

OP
it depends, if it is finished surface or if there is stock removal, for machining.
even if not required follow the AMS 2759/3
procedures. finished surface in a Vacuum, or inert atmosphere. prevent oxidation. precipitation harden. run with specimens for testing.

We used to do both.
HT some samples in the lab and some with the parts.
Served to verify both the material and the HT.
And nitrogen is not an inert atmosphere.
The alloy will absorb some at the annealing temp and it mess with the phase balance.

Greetings.

Thank you for your reply.

I would like to express my concern regarding the necessity of verifying the mechanical properties of the casting. It is of the utmost importance that these tests be performed separately from the part. However, the test pieces are too small in relation to the casting to be placed in the same furnace. This could result in an over-treatment, which would incur an excessive cost if the heat treatment is done separately. Are there any alternative options for the heat treatment?

I have reviewed the standard procedure, and I have found that it is possible to order a square "cupon" that will be machined after the heat treatment for the test. This will reduce the probability of over-treatment and allow the casting and the "cupon" to be placed in the same furnace.

What is your professional opinion on the feasibility of this approach?