17-4 HH1150 to H900 3

[suthagarqa]

Hi Team,

Please share the Heat Treatment process involved in transform 17-4 HH1150 to H900 Condition.
Especially quenching temperature & holding hours and tempering.

Thanks.

 

[metalonis]

17-4PH in condition H1150 must be re-annealed first, 1900 ± 25°F [1040 ± 15°C) and cooled to below 90°F [32°C). Then precipitation hardened, 900°F (480°C) and air cooled to attain condition H900.

 

[metengr]

http://www.aksteel.com/pdf/markets_products/stainless/precipitation/17-4_ph_data_bulletin.pdf

 

[suthagarqa]

But our Heat Treatment supplier did different process. Quenching at 1020°C for 2.5 Hours and Tempering at 508°C for 5 hours.
Is that correct process?

 

[EdStainless]

Where did he come up with that HT?
There is an AMS spec for this.
You need to check the properties.
Do you need to meet impact toughness?
If so you had better check tests, you may need to re-heat treat it.

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P.E. Metallurgy, Plymouth Tube

 

[tbuelna]

First, probably not a good idea to use 17-4PH in an H900 condition.

Second, as others noted it is not possible to "transform" 17-4PH H1150 directly to H900. You need to start by re-annealing the material.

You can refer to specs like MIL-H-6875 or AMS 2759/3 for guidance on heat treatment of 17-4PH. The process times can vary based on material section thickness.

In the future it would be a good idea to provide explicit requirements to your HT vendor regarding processing and QA of the delivered product. Don't rely on your vendors to do your homework for you.