431SS losing it quality

[123Cat]

Good afternoon

I am tempering 431 in the range that adversly effects corrosion resistance

I suppose its the chrome thats depleted

Final hardness is 42 Rc

My part runs at 40,000 PSI in pure water

Would pressure also deplete corrossion resistance

 

[123Cat]

Sorry
Pure water inside at 40,000 PSI no temp

 

[EdStainless]

You have to temper above 1100F or below 800F.
If you are in that range you not only loose corrosion resistance but the alloy will be very brittle.
42 RC, you get that with 1100F temper (or maybe 1050F), and good toughness and corrosion resistance.
Did you descale and passivate? This is necessary.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[metengr]

Would pressure also deplete corrosion resistance

No.

 

[123Cat]

No we did not descale and passivate
And we are getting crack failure in these parts

They are vac heattreated and we will work on your advise

thanks a heap

 

[EdStainless]

if you are getting cracks you need to look more closely, are they impact or fatigue?
Raise the temper to 1100F, and get the surfaces clean.
How much general corrosion (rusting) is there?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[123Cat]

They would be cyclic fatigue cracks as its been in service a while , then all of a sudden it leaked
and yes corrosion is there
as no passivation was done
Will beat on them to do the chemical corrosion prevention

Thank you