Question on 1018 and stress relieving
Close
Login to Your Account
Results 1 to 12 of 12
  1. #1
    Join Date
    Aug 2005
    Location
    CT
    Posts
    7,877
    Post Thanks / Like
    Likes (Given)
    331
    Likes (Received)
    1913

    Default Question on 1018 and stress relieving

    Guys

    I'm about to start a kind of epic job.
    Just over 700 complete assemblies of 8 components / each.
    6 of the components are 1018, the other 2 is A2 at HRC 60+.

    The A2 parts are given and of no concern.
    My issue is with some of the 1018 details.
    They are made from a rectangle bar of 2 x 3, are approx 6" long, and when done they are pretty much like swiss cheese.
    Large(r) holes, slots, thin walls ... 70+% of the material is machined away.

    None of the tolerances are stupid tight on the print, but I do foresee issues with proper fit if something moves or twists during machining.
    From my experience, I've seen plane-jane 1018 do unexpected things at some of the times, and be completely stable at others.

    So my question: Would it be a worthwile attempt to saw cut the blanks from the bar and send them out for annealing, normalizing, stress relieving or ( add the proper term here )?
    Cost or added time is of no concern here.
    Trouble free machining IS !!!

    Thank You

  2. #2
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    823
    Post Thanks / Like
    Likes (Given)
    77
    Likes (Received)
    281

    Default

    Quote Originally Posted by SeymourDumore View Post
    Guys

    I'm about to start a kind of epic job.
    Just over 700 complete assemblies of 8 components / each.
    6 of the components are 1018, the other 2 is A2 at HRC 60+.

    The A2 parts are given and of no concern.
    My issue is with some of the 1018 details.
    They are made from a rectangle bar of 2 x 3, are approx 6" long, and when done they are pretty much like swiss cheese.
    Large(r) holes, slots, thin walls ... 70+% of the material is machined away.

    None of the tolerances are stupid tight on the print, but I do foresee issues with proper fit if something moves or twists during machining.
    From my experience, I've seen plane-jane 1018 do unexpected things at some of the times, and be completely stable at others.

    So my question: Would it be a worthwile attempt to saw cut the blanks from the bar and send them out for annealing, normalizing, stress relieving or ( add the proper term here )?
    Cost or added time is of no concern here.
    Trouble free machining IS !!!

    Thank You
    it would help if you cut the scale off 1st and pop a hole or 2 in it.. then normiize harden and temper.
    if you send to before you cut it will spring like heck when you take the scale off.

  3. #3
    Join Date
    Jun 2012
    Location
    Tennessee USA
    Posts
    792
    Post Thanks / Like
    Likes (Given)
    473
    Likes (Received)
    467

    Default

    I'm certainly no authority on the subject but if concerned about warping the part then my experience would suggest roughing the part and leaving stock on more critical features. Have it stress relieved or normalize (different process/results) followed by final machining. There's definitely a possibility of the parts coming back from HT very changed regarding flatness, especially if you're removing 70% of the material so the potato chip effect may call for a face cut on top/bottom if that matters. No mention made on fitment/feature critical tolerances so I can't offer a valid opinion. "Trouble free machining" can mean a lot of different things and a wide range of tolerance values. If time/money is less of a concern I'd give the HT a call. Stress relieving the material can also relieve some of the stress on you. You already have enough to worry about. Good luck.

  4. #4
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,213
    Post Thanks / Like
    Likes (Given)
    4598
    Likes (Received)
    1899

    Default

    If this is cold-finished 1018, I'd not worry too much about through holes. Removing material from one face, however, can cause the bar to curl up like a banana. Not talking tenths of thousandths, but tenths of inches removing about half the thickness of some 1/4x1 bar for about 8" length. Stress relieving should help considerably with that behavior.

  5. #5
    Join Date
    Apr 2018
    Country
    UNITED STATES MINOR OUTLYING ISLANDS
    Posts
    3,859
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1742

    Default

    Rough, stress relieve, finish machine.

    Better safe than sorry.

  6. #6
    Join Date
    Sep 2011
    Location
    Langley, B.C.
    Posts
    1,745
    Post Thanks / Like
    Likes (Given)
    368
    Likes (Received)
    1021

    Default

    You need to bear in mind that the stresses induced in cold-finished material are mechanical and not
    necessarily related to any heat treat process. I would be inclined to experiment with a couple samples
    to see if annealing removes all of the internal stresses...

  7. #7
    Join Date
    Aug 2005
    Location
    CT
    Posts
    7,877
    Post Thanks / Like
    Likes (Given)
    331
    Likes (Received)
    1913

    Default

    Quote Originally Posted by EmanuelGoldstein View Post
    Rough, stress relieve, finish machine.
    Can't do! ( And that applies to milling, drilling or otherwise removing "some" material prior )
    Material in -> ??? - > Machine -> Finished part out.


    'Bout the better safe then sorry part .... We'll try to make it work.


    At some point in the past I was told that a stress relieved block cut from A36 plate was better to machine complete than using a 1018 rectangular bar for the same.

    Machined both.
    The A36 flame-cut plate + "whatever treatment" process was always reliable, but having to square shit up first was a bitch.
    1018 Flat bar was always easier ( quicker ) to process from the get-go, but I often had to deal with some of "this and that" for the final ops.

    To date I've never had this many pcs to process from the same material, so I'm asking what would be better....

  8. #8
    Join Date
    Jan 2007
    Location
    Pinckney Mi.
    Posts
    2,993
    Post Thanks / Like
    Likes (Given)
    5796
    Likes (Received)
    876

    Default

    I might suggest HRS instead of CRS, bar stock,not flame cut,might.....
    good luck,sounds exciting.
    Gw

  9. Likes TDegenhart, Matt_Maguire liked this post
  10. #9
    Join Date
    Apr 2018
    Country
    UNITED STATES MINOR OUTLYING ISLANDS
    Posts
    3,859
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1742

    Default

    Quote Originally Posted by SeymourDumore View Post
    Material in -> ??? - > Machine -> Finished part out.
    Kerpoopie

    All I can think then is, second vote for GW's idea, use hot rolled instead of cold finished. One less batch of mechanical stress in the raw material.

  11. #10
    Join Date
    Apr 2011
    Location
    San Diego
    Posts
    775
    Post Thanks / Like
    Likes (Given)
    58
    Likes (Received)
    202

    Default

    Won't annealing the 1018 reduce the tensile strength of the part? I had a part I had to machine out of 1018 that was 1/2" thick stock and about 25" long. Ended up doing three sets of passes to get to the right thickness (around 10mm iirc). Each time the part was flipped it would warp a bit less.

  12. #11
    Join Date
    Dec 2008
    Country
    UNITED STATES
    State/Province
    New York
    Posts
    10,235
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2657

    Default

    Quote Originally Posted by SeymourDumore View Post
    Guys

    I'm about to start a kind of epic job.
    Just over 700 complete assemblies of 8 components / each.
    6 of the components are 1018, the other 2 is A2 at HRC 60+.

    The A2 parts are given and of no concern.
    My issue is with some of the 1018 details.
    They are made from a rectangle bar of 2 x 3, are approx 6" long, and when done they are pretty much like swiss cheese.
    Large(r) holes, slots, thin walls ... 70+% of the material is machined away.

    None of the tolerances are stupid tight on the print, but I do foresee issues with proper fit if something moves or twists during machining.
    From my experience, I've seen plane-jane 1018 do unexpected things at some of the times, and be completely stable at others.

    So my question: Would it be a worthwile attempt to saw cut the blanks from the bar and send them out for annealing, normalizing, stress relieving or ( add the proper term here )?
    Cost or added time is of no concern here.
    Trouble free machining IS !!!

    Thank You
    .
    1) depends on tolerances of part
    .
    2) stress relieving in bulk doesnt cost that much. that is when furnace is filled to max with parts as opposed to only one part the cost per part to stress relieve is low. Say its $100. to heat furnace, energy and labor. obviously if there is over 100 parts in the furnace compared to one part the cost per part is different.
    .
    2)consistency of parts. tracking total time to make a part including rework, remaking often its cheaper and faster to do many things that at first seem more expensive or slower
    .
    3) parts warping yes many will warp or curl immediately after unchucking but many parts need time and will continue to warp or curl after some time has gone by. thus rechucking and taking finish cuts part can easily still warp or curl some more later
    .
    4) A36 plate can be full of stress, obviously anybody using a jig saw, saber saw or sawsall cutting shape out of a sheet and have saw kerf close up at the last part of cut, seen it thousands of times can tell you that. A36 can also be full of larger hard spots of slag compared to rolled stock. also A36 sheet when sheared if piece sheared is small width the shearing induces a large amount of stress into the part often worse than if piece was just cold rolled steel
    .
    4) hot rolled is not necessarily stress relieved. if rolling continues and steel bar was below red heat its same as cold rolling. cold rolled has mill scale pickled off with chemicals. basically hot roll can be under same cold rolled stress it just didnt get pickeled or chemical treatment to remove mill scale. sometimes cold rolled after chemical treatment is a smoother shape and could be more accurate to nominal size and shape. doesnt mean that after machining it will not warp or curl. some cold rolled parts might only get cut to length and a few holes drilled thus warpage often not a issue

  13. #12
    Join Date
    Feb 2012
    Location
    California
    Posts
    1,411
    Post Thanks / Like
    Likes (Given)
    892
    Likes (Received)
    1523

    Default

    Yes, I would absolutely send these out for stress relief. Makes a huge difference.

    Heat treaters charge by the pound. Around here, $0.30-$0.40 per pound with a $150 lot minimum. 1018's pricey these days so stress relief is a minor cost component, but should still be factored in.

    In a pinch I've done it in house. Heated to 1500F, just under austenitizing temp, then furnace cooled overnight.

    Quote Originally Posted by dksoba View Post
    Won't annealing the 1018 reduce the tensile strength of the part? I had a part I had to machine out of 1018 that was 1/2" thick stock and about 25" long. Ended up doing three sets of passes to get to the right thickness (around 10mm iirc). Each time the part was flipped it would warp a bit less.
    1018 specifications are in the annealed state. The low carbon indicated by the "18" makes it so that it'll only harden through a case hardening method, e.g. carburization.

  14. Likes Philabuster, Bobw liked this post

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
  •