Heat treating without foil?
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 31
  1. #1
    Join Date
    Jun 2017
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    7
    Likes (Received)
    14

    Default Heat treating without foil?

    Is there any negative side effects of heat treating air hardening tool steels without wraping them other than scale?A2 and A6 specifically

    Sent from my SM-G973U using Tapatalk

  2. #2
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,172
    Post Thanks / Like
    Likes (Given)
    4473
    Likes (Received)
    1878

    Default

    In addition to scale, you may have softening of the surface due to decarburization. There was a thread here not to long ago about A2 parts that 1) looked oxidized, and 2) had a soft surface. Our collective best guess was exposure to O2 atmosphere during heat treat.

  3. Likes Hopefuldave liked this post
  4. #3
    Join Date
    Apr 2006
    Location
    Suffolk, England
    Posts
    884
    Post Thanks / Like
    Likes (Given)
    95
    Likes (Received)
    239

    Default

    Has anyone tried the old-fashioned soft soap method for preventing decarb?
    Over here in the UK, stainless foil bags or wrap are hard to come by - we can order some online, but they're shipped from the US or China.
    So, would soft soap work for onesy-twosy parts? And what is the 'right' sort of soft soap? There's is plenty available from places like pottery supply retailers.

  5. #4
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    16,137
    Post Thanks / Like

    Default

    Why not the old method of a steel plate box and bone or charcoal ?

    Or steel filings if you don't want to carburize.

  6. #5
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,373
    Post Thanks / Like
    Likes (Given)
    178
    Likes (Received)
    931

    Default

    I have used soap to heat treat in my forge and yes it does work.

  7. #6
    Join Date
    Sep 2005
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    99
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    9

    Default Roach poison

    I use powdered boric acid, sold as roach and ant killer. Heat the part up just a bit then dip it into the powder, which will stick to the hot part. When you continue to heat the part the boric acid turns into a thick liquid that coats the part. A water quench will cause the coating to crack and completely fall off. Oil quenching doesn’t always get rid of all of the coating, but what’s left is pretty easy to clean off.

    Easy, effective, cheap, and available.

    Dave

  8. Likes Scottl, Dumpster_diving liked this post
  9. #7
    Join Date
    Oct 2010
    Location
    Dewees Texas
    Posts
    2,437
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    667

    Default

    Quote Originally Posted by DaveRobinson View Post
    I use powdered boric acid, sold as roach and ant killer. Heat the part up just a bit then dip it into the powder, which will stick to the hot part. When you continue to heat the part the boric acid turns into a thick liquid that coats the part. A water quench will cause the coating to crack and completely fall off. Oil quenching doesn’t always get rid of all of the coating, but what’s left is pretty easy to clean off.

    Easy, effective, cheap, and available.

    Dave
    This has worked for me in treating small part made from W1 and such. For A2 and A6 I might be inclined to cover parts with boric acid which necessitates putting the parts and powder in a container, I have used one made of stainless foil for this. Parts made form A2 or A6 will be hot for a lot longer time and the boric acid may run off. Some metals such as 416 can be eaten up by the acid. Not sure why one metal is eaten up and another not. Try a sample first.

  10. #8
    Join Date
    Nov 2013
    Location
    Eastern Massachusetts, USA
    Posts
    4,535
    Post Thanks / Like
    Likes (Given)
    4653
    Likes (Received)
    4644

    Default

    Quote Originally Posted by Peter Neill View Post
    Has anyone tried the old-fashioned soft soap method for preventing decarb?
    Over here in the UK, stainless foil bags or wrap are hard to come by - we can order some online, but they're shipped from the US or China.
    So, would soft soap work for onesy-twosy parts? And what is the 'right' sort of soft soap? There's is plenty available from places like pottery supply retailers.
    I've used that on water and oil hardening. Basically you want a quality soap of better make. If it can be used for hand washing and gradually wear down to a sliver without either cracking or turning to mush (which cheap soaps do) it should be suitable. You rub it on as soon as the steel is hot enough to leave a streak of soap.

  11. #9
    Join Date
    Jul 2006
    Location
    rochester, ny
    Posts
    1,943
    Post Thanks / Like
    Likes (Given)
    401
    Likes (Received)
    559

    Default

    When hardening A2, does the speed of cooling matter?

  12. #10
    Join Date
    Jun 2017
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    7
    Likes (Received)
    14

    Default

    Quote Originally Posted by sfriedberg View Post
    In addition to scale, you may have softening of the surface due to decarburization. There was a thread here not to long ago about A2 parts that 1) looked oxidized, and 2) had a soft surface. Our collective best guess was exposure to O2 atmosphere during heat treat.
    I was afraid they would end up soft like that, guess I'm going to order some stainless foil, it's a pretty decent job but the parts are little less than a half inch square so didnt seem worth it to order 50 feet lol

    Sent from my SM-G973U using Tapatalk

  13. #11
    Join Date
    Jun 2017
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    7
    Likes (Received)
    14

    Default

    Quote Originally Posted by richard newman View Post
    When hardening A2, does the speed of cooling matter?
    I think it's only critical to be exposed to oxygen from like 1800/1650

    Sent from my SM-G973U using Tapatalk

  14. #12
    Join Date
    Jun 2014
    Location
    Kansas City
    Posts
    738
    Post Thanks / Like
    Likes (Given)
    102
    Likes (Received)
    469

    Default

    Could you put the parts in a piece of pipe with caps on the end? Maybe put some paper in with the parts to burn up the oxygen?

  15. #13
    Join Date
    Oct 2014
    Country
    CANADA
    State/Province
    Ontario
    Posts
    1,270
    Post Thanks / Like
    Likes (Given)
    754
    Likes (Received)
    1041

    Default

    Quote Originally Posted by richard newman View Post
    When hardening A2, does the speed of cooling matter?
    Yes it does, a lot! Oil quenching A2 will leave you with a piece so hard that it will be difficult to temper it back to something reasonable, the part will also have very low toughness and may crack during quenching. Water quenching A2 is just a big 'no no'.

    A2 quenching is best done by simply hanging the part in still air. Hanging is better than putting it on a flat surface as the side facing the surface will cool slower and the part will warp. If the part is big and needs support then cooling is on a steel mesh table is probably best.

    Avoid cooling the part with a fan or compressed air as again this will cause uneven cooling and warping.

    If you need to heat-treat without foil the simplest way I have found is to use an 'anti-scale' compound like ATP-641 from Brownells. This is basically a clay 'slip' (thin mixture of clay and water) that you apply to the part after thorough de-greasing. The clay dries on the part and forms a barrier. During the quench the clay will crack and spall off the surface, you do not need to oil quench to get it to crack. You can also clean up the final part by bead-blasting to remove any remaining clay without damaging the steel surface underneath.

    With all that said: heat-treating in foil will still get you a better result and a better looking part. Even better would be to seal up the outside of your furnace and then plumb it for inert gas like Argon. A small flow of argon during the heating process will drastically reduce or eliminate scale/decarb.

  16. #14
    Join Date
    Oct 2014
    Country
    CANADA
    State/Province
    Ontario
    Posts
    1,270
    Post Thanks / Like
    Likes (Given)
    754
    Likes (Received)
    1041

    Default

    Quote Originally Posted by Erstwhile View Post
    I think it's only critical to be exposed to oxygen from like 1800/1650

    Sent from my SM-G973U using Tapatalk
    Any temperature over 400ºF will start growing an oxide layer on the part. Any temperature over about 900ºF will start causing decarburization/scale (albeit slowly at first). Best thing is to protect the part the whole way through the heating/quenching process.

  17. #15
    Join Date
    Mar 2005
    Location
    Kansas
    Posts
    7,639
    Post Thanks / Like
    Likes (Given)
    440
    Likes (Received)
    3543

    Default

    But don't use the anti-scale in an electric furnace.

  18. #16
    Join Date
    May 2012
    Location
    Pittsford, NY
    Posts
    1,055
    Post Thanks / Like
    Likes (Given)
    726
    Likes (Received)
    680

    Default

    Gbent, can you explain?

  19. #17
    Join Date
    Oct 2014
    Country
    CANADA
    State/Province
    Ontario
    Posts
    1,270
    Post Thanks / Like
    Likes (Given)
    754
    Likes (Received)
    1041

    Default

    Quote Originally Posted by gbent View Post
    But don't use the anti-scale in an electric furnace.
    I have done this many times without issue.

  20. Likes Hopefuldave liked this post
  21. #18
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,373
    Post Thanks / Like
    Likes (Given)
    178
    Likes (Received)
    931

    Default

    I think what Gbent is referring to is when you use boric acid in an electric furnace, it runs down on the bottom and soaks into the firebrick. It is almost impossible to remove. Been there done that.

  22. #19
    Join Date
    Feb 2001
    Location
    Redwood City, CA USA
    Posts
    5,007
    Post Thanks / Like
    Likes (Given)
    187
    Likes (Received)
    925

    Default

    Quote Originally Posted by crossthread View Post
    I think what Gbent is referring to is when you use boric acid in an electric furnace, it runs down on the bottom and soaks into the firebrick. It is almost impossible to remove. Been there done that.

    The borax fumes also attach the elements. BTDT.

  23. #20
    Join Date
    Oct 2014
    Country
    CANADA
    State/Province
    Ontario
    Posts
    1,270
    Post Thanks / Like
    Likes (Given)
    754
    Likes (Received)
    1041

    Default

    Gotcha, makes sense. The anti scale I mentioned (ATP641) is not borax based and is fine to use in an electric furnace. ATP641 from Brownells has worked well for me many times in an electric furnace with no noticeable ill effects on my furnace!


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •