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what is 4140 steel?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by DaQo'tah Forge, Dec 16, 2003.

  1. DaQo'tah Forge

    DaQo'tah Forge Banned by Moderators

    Aug 26, 2002
    today I was talking to a guy at a place that has tons of steel,,,and he asked me about my knife on my hip,,,so I told him I made it myself,,,and he took me to the back and showed me a huge pile of steel that i could pick out what i wanted,,,'

    he said the steel would get hard if heated and quenched in oil...

    I looked up the numbers for the steel and saw it was listed as 4140 steel

    Now I have used 52100 and 5160,,,but never have I even heard of 4140 steel...

    anyone think it would be worth forgeing?
  2. C. Marlowe

    C. Marlowe

    Oct 11, 2001
    If memory serves, that is an ordanance steel used for gun recievers etc. I have no idea on using it for knives, take a look at the chem analysis and try a test piece. - Charles
  3. DaQo'tah Forge

    DaQo'tah Forge Banned by Moderators

    Aug 26, 2002
    got off the phone with the guy,,asked him about your post,,,,he looked it up, and althought he said tons of things that were likely important,,I didnt understand a thing he said..

    However he told me that based on the 41 part of the 4140 name of this steel. that he 'thinks" this steel is a "mild carbon" steel

    Now this I understand to mean is not the same as 'mild steel"?

    he says that 4140 does get hard,,,so this tends to make me think that it is not just normal "mild steel" as that stuff is said to not be able to harden...
  4. Bruce Bump

    Bruce Bump KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 2, 1999
    4140 is a good steel for gun parts, barrels and knife fittings. It just barely has enough carbon content to harden. It wouldnt make a decent blade but It takes on the best deepest blues in the world. You should see it with Nitre Blue!
  5. DaQo'tah Forge

    DaQo'tah Forge Banned by Moderators

    Aug 26, 2002
    The reason I went to his store in the first place is that I was looking for a store that might stock 5160 or 52100 steel. My John Deer load shaft supply has about dried up on me,,,,the new tractors do not have load shafts...

    He looked in his stock books for my steel, but
    He had never heard of such steel for sale in my town..

    I need to find a cheap way to get 5160 steel that is as clean as load shafts, and is big enough to allow me to work the steel in my forge....(because it's fun thats why).
  6. Ed Caffrey

    Ed Caffrey

    Jul 23, 1999
    The "41" designates this steel as a Chrome/Moly steel. The "40" indicates the amount of carbon present measured as .040%. It is very often used for gun barrels/receivers. It is not highly hardenable, but is very impact resistant when heat treated, which makes it an excellent choice for the types of pressures present in gun barrels. Most modern made power hammer dies are also made from this type of steel. I keep small amounts of it around the shop for creating specific impact type tools such as texturing dies, larger hot punches, and of course the odd die for the power hammers.
  7. DaQo'tah Forge

    DaQo'tah Forge Banned by Moderators

    Aug 26, 2002
    okay....clearly it is not worth the effort to forge into a knife...

    too bad,,,,it would have been free....perhaps thats why it was free..

    On another topic here on the BF, there was a guy showing his knife that he had forged from some rebar.

    well, he said that he used some type 60 rebar and not to use the type 40 rebar.

    so ,,,because I need to find some free steel to forge this winter,,,I went down to the local grand Forks lunbar yard and looked at the 2 and 4 foot rebar

    all I could find on the rebar was something about the fact that it was made in Mexeco.

    not much help...
  8. rlinger


    Mar 29, 2002
    I have some, though I thought mine might be 4160, from Douglas Barrel and it is great - really great - for rolling stainless foil packet folds for heat treating. Any one doing their own stainless heat treat in foil needing a heavy steel rolling pin can email me and for postage I'll send you an adequate piece.

  9. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    4140 is an excellent steel, an excellent combination of strength vs cost .Used for rifle barrels ,aircraft tubing , high strength bolts etc.For knives however it doesn't have enough carbon to create a very wear resistant edge.
  10. Danbo

    Danbo Platinum Member Platinum Member

    Nov 28, 1999
    If it's free, I would get some from the guy. You could always use it for blued guards and buttcaps.

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