Trying to determine whether the 17-4 PH valve stem is suitable for -50°F

[Hugo G]

Hello,

We're currently working in this order to supply 50 MOVs to a gas production company, their min temperature is -50°F, our valves are from PBV and we've already asked them, however i haven't found any information regarding the temperature range for the 17-4 PH steel, i'd would like to know if this 17-4 PH stem could work correctly at these temperatures.

 

[metengr]

What is your specified heat treatment condition for the 17-4PH? Also, more important, what minimum CVN value at -50 deg F do you need to meet?

 

[MagBen]

Overage material to get some reverted austenite to improve impact properties at low temperature. In terms of strength, -50F will make material stronger, while keep the same ductility.

 

[pradipgoswami]

Hi You may find some information on impact properties of 17-4 pH steel in the following data sheet. However the data is for bars, which are forged products. Valves involves a lot of casting, hence the mechanical properties may fluctuate widely. One has to be very careful about selection and getting the components conforming to good impact values at -50 Deg F. Also note any welding on 17-4 steel could be highly problematic
Duplex 2205 may be another material to consider.

Thanks.

http://www.interlloy.com.au/our-pro...ion-hardening-stainless-steel-bar/?output=pdf

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[metengr]

Why bother using 17-4PH for a valve stem. I would use Nitronic 50 and be done with it. This is material typical for valve stems.

 

[Hugo G]

Just got answer from mfg and the stem is going to be ASTM A564 GR 630 H1150D, 25 ft-lbs min avg for 3 specimens on CVN at -75F

 

[metengr]

This should be acceptable for the valve stem application.