Two steels one heat treat?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by eric brinkerhoff, Jan 16, 2020.

  1. eric brinkerhoff

    eric brinkerhoff

    Mar 10, 2013
    I have two blades I made a while back and I cant remember what steel is in each blade. I do know that one is cpm s30v and one is cpm s35vn, I just dont know which is which. Looking at the Crucible data sheets the heat treatment for these steels appears to be very similar. I plan to send these blades to Peter's . They do have a way to tell what kind of steel it is but it is expensive. Im wondering if I could call both knives one steel or the other and let them heat treat both the same way. These knives will not be for sale.
  2. Big Chris

    Big Chris SAHD/Knifemaker Knifemaker / Craftsman / Service Provider

    Apr 1, 2010
    S30V and S35VN can both be austenized around 1950 to 2000 and tempered between 400 and 600.
    SBuzek and bikerector like this.
  3. eric brinkerhoff

    eric brinkerhoff

    Mar 10, 2013
    Maybe I should just take a wild guess as to which Steel and label the blades. Maybe one of the blades will be slightly less optimal but who cares.
    Scaniaman likes this.
  4. Busto

    Busto KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jul 26, 2011
    Here's a thought: Why not call and ask them what the best approach is for sending in the "Unknown" since you know what Steel they are but not sure which is which. I'm sure they can give you some guidance rather than leave it to chance. I would bet they have dealt with this situation before...
  5. daizee

    daizee KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2009
    I'd harden those the same, though maybe you want to temper the S30V lower for less chippiness?
    You could harden them the same, temper both at the lower temp, and then do an additional temper for one of them when you figure out which is which.
  6. Joel Mercier

    Joel Mercier

    Dec 3, 2017
    S35vn is easier to finish so you may ultimately figure which is which.
    eric brinkerhoff likes this.
  7. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    I would have them done with the same protocols. I use 1950°F and 400°F for both steels.

    We all have a couple blades (or bars of steel) we just can't remember what it is.

    A way to avoid this in the future is to keep a white paint type metal marker in the shop by the bench. The old adage is, "You can't forget what you write down."
    Mark all metal bars on both sides of each end when you get it.
    Mark all blades on both sides of the tang when you cut them out.
    Mark them again if needed when you grind them.
    When you send them off for HT ( or if do your own) mark your initials and any notes for the HTer on the blade and tang. (SEA, S35VN, Rc62)
    The white paint will turn dark in the HT, but will still be there after HT until you grind it away in finishing.
    If you will be finishing the knife in delayed steps, mark the tang with a black sharpie until you install the handle.
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  8. eric brinkerhoff

    eric brinkerhoff

    Mar 10, 2013
    Thank you all for your replies!
  9. Natlek


    Jun 9, 2015
    If you make knives for sale i don t see any reason why you should not sell this two .If I m customer for one of them , your simple explanation that you are not sure which knife is in which steel is enough for me .Both steel are enough close so I would buy one , the one I like more ...
    eric brinkerhoff likes this.
  10. eric brinkerhoff

    eric brinkerhoff

    Mar 10, 2013
    One of the blades in question.
  11. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    I have a $50.00 electric engraver I use to mark the steel type on tangs when I profile blades. I used to mark all steel with sharpies, but that can fade over time, so I use a grease pen or paint pen now. I prefer grease pens. I mark every 8-10” so I always know what the steel is.

    regarding selling, let the potential customer know what happened. The steels are so similar that the end result will be nearly the same. S30vn will hold an edge slightly better, where S35vn will finish a little easier and have slightly better corrosion resistance. Check out Larrin’s last article on heat treating these steels. I’m changing my process because of his testing.

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