Heat treating S30V

[Tony Painter]

I have just finished a folder with an S30V blade. I ground and finished the blade prior to heat treating, taking it down to a 600 grit hand rubbed finish and it looked great. After heat treat and cleaning up the scale I noticed some staining towards the blade tip that almost has the look of a hamon mark. Can anybody give me any pointers as to what caused this and does it reflect on the hardness of the blade?

[mete]

Just how did you heat treat it .What scale ?Did you use foil ? Did you use a getter in the foil ?[ a getter is something like paper or metal chips which 'get' or tie up the oxygen]

[Tony Painter]

I wrapped it in ss foil with a small piece of paper inside, as I always do when doing other ss blades. When I say scale I suppose I should say tarnish. I took the oven to 1950F and held it there for 30 min, then did two, one hour quenches at I think it was 600F. When I took the blade out of the oven after the 1950 soak I quenched it between two steel plates while it was still wrapped in the foil. Should I have air quenched it? This is only the second time I have worked with S30V, normally I use ATS 34.
Thanks for the repy Mete

[RJ Martin]

Tony: Sounds like you did the HT correctly. I'm assuming you meant tempers, not quenches @600F. BTW, 2 hours is recommended for each tempering cycle-Not sure how much difference you'll see in a small blade like yours. Probably none.

I do not put anything inside the foil packets eccept blades. I have found this produces the most consistent results. You are always going to see some minor surface effects on your blades, which is why I would advise against finishing them completely before HT. Other than having to clean up the surface of the blade, sounds like you'll be fine.

[Tony Painter]

Thanks for the reply and letting me know I have done the heat treat as I should have. I will leave the finishing until after the heat treat next time, maybe it will make a difference, although I don't relish working on hardened S30V, especially the hand sanding. I guess that is the price of using these fancy steels!

[Tony Painter]

I did another blade yesterday, this time leaving out the paper and it turned out beautifully, so thanks for that tip. Do you use this system with all stainless? I was always under the impression that putting paper inside the package was recommended, to burn up excess oxygen and thereby leave a cleaner blade.

[tmickley]

S30V comes out of heat with a different patina than ATS-34. It's more of a gold with rainbow kinda look here and there. ATS-34 is usually just gray with the occasional rainbow splash.

[Tony Painter]

That's exactly how it came out, which is encouraging, I am fairly new to doing my own heat treating. Should I be putting paper in the packet when treating ATS34?

[RJ Martin]

Tony: I never use any combustible inside the pack.

[Tony Painter]

I have just finished polishing the above S30V blade and am again left with staining marks on the blade which can be seen under certain light, as I experienced with the first S30V blade I did. The steel came from Admiral and I did the heat treat myself. Has anybody else had this experience?

[Jerry Hossom]

You polished S30V, as in mirror polished? That doesn't sound right. It is VERY difficult to "polish" S30V if it's fully hardened. In any event there shouldn't be any color. That can happen if the steel overheats while finish grinding though.

[RJ Martin]

Tony: How much re-grinding did you do after HT?

[Tony Painter]

I didn't mirror polish but took the ricasso area down to 1500 grit and hand sanded the blade area down to 600 grit and then went back to 400, hoping the staining would be less visible. I also finished all the grinding of the blade prior to heat treating. The blade never got too hot during grinding as I always push with my thumb so would immediately feel any heat build up. Like I say the staining is only visible if the blade is tilted to catch the light, it's one of those frustrating things that doesn't affect the performance of the knife, only the esthetics.

[RJ Martin]

Tony: Without seeing a pic, it's hard to say, but, my guess is that you had some surface effects that didn't get sanded out during your finishing operations.

[Tony Painter]

Yes, I had thought about that but I took the blade down to 600 grit and was wearing an opti-visor to ensure there was no evidence of scratches. This is the process I have always followed when using ATS34, D2, etc and have never had previous experience of it, which makes me wonder if it is the steel.
Anyway, thanks for all your responses.