17-4PH cold rolling

[gpss]

Can anyone tell me what's the exact process to cold roll 17-4PH from say 4mm thickness sheet to 0.4mm ? That's a 90% reduction...considering at 4mm we start with 17-4PH "A" conditions, how many times the alloy needs to be heat treated, annealed, re-heat treated, re-annealed etc. ? What's the amount of cold reduction possible in a single pass ?

Ajit Pai

 

[EdStainless]

I am not sure about sheet, but I have seen wire drawn in the overaged condition. It has better ductility overaged than annealed, and it strain hardens less.

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Plymouth Tube

 

[gpss]

Thanks ED. Overaged is Double heat treated at 1150 right ? What's the maximum reduction possible in this condition ? am I right to assume approx. 20% ? Further re-anneal, re-overage and cold draw again ? Repeat the process till you achieve the desired reduction ?

Ajit

 

[unclesyd]

At times when we had do severe coining on 17/4 parts we would go to the H1150-M heat treatment.
2 hrs at 1400F
air cool
4 hrs at 1150F
air cool

We have heat treated the same part with this procedure several times.

 

[gpss]

Thanks ED. Overaged is Double heat treated at 1150 right ? What's the maximum reduction possible in this condition ? am I right to assume approx. 20% ? Further re-anneal, re-overage and cold draw again ? Repeat the process till you achieve the desired reduction ?

Ajit

 

[EdStainless]

I don't know the strain hardening coef, but since other grades are often reduced 40-60% I would think that you could get close to that with this alloy.
In wire work they don't reanneal, they just re-over age. That works as a stress relief.

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Plymouth Tube