Localized Heat Treatment for 17-4
Localized Heat Treatment for 17-4
(OP)
I have some cast 17-4 pipe (5/8"OD 3/8" ID) that has been heat treated to H925. I would like to make a section of this tube more ductile so I can bend it slightly. I have access to an induction coil. Is there a localized heat treatment that I could perform that would make the material easier to bend?





RE: Localized Heat Treatment for 17-4
I would be concerned about doing it locally using an induction coil because of a possible Heat Affected Zone adjacent to ends of the coil. I will admit that my experience with induction coils is nil, so take my thoughts under consideration but do more research.
RE: Localized Heat Treatment for 17-4
You should review the information from AK Steel on 17-4 material;
http://www.aksteel.com/pdf/markets_products/stainl...
RE: Localized Heat Treatment for 17-4
In the H925 you need a minimum elongation of 10%, if the actual value isn't at least 14% I would be concerned about the material.
If you heat the whole piece to 900F, and then hot bend you will not need to do any re-heat treatment.
If you need a very accurate bend hot bending is probably not your answer though.
We used to do this for very general bends, we filled sections with Olivine sand (MgO, not SiO2) to support them when bending since you can't use ID tooling hot. We made OD form out of Oak and charred them, they held up very well.
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Plymouth Tube
RE: Localized Heat Treatment for 17-4
RE: Localized Heat Treatment for 17-4
If you could use a multi-zoned furnace and heat the entire part to 900-925F, and the bend section to 1000-1025F.
If you can't then just insulate the entire part that is not being heated.
You want to minimize temperature gradients or you could get a lot of distortion.
There are companies that do field HT work by wrapping insulted elements directly onto the parts. That would work for this.
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Plymouth Tube
RE: Localized Heat Treatment for 17-4
if slightly bending, you probably no need to re-age for a residual stress relief. For a heavy deform, you do need to re-age to restore tooughness.