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  • 1.  Draw Bench math

    Posted 12-14-2023 18:29
      |   view attached
    Material Handbook 9th Editition, Volume 14
    Forming and Forging, pg 331
    Wire, Rod, and Tube Drawing
    Aproach Angle  Δ
     deformation zone  Δ ( α rad/γ)*(1+(1-γ)^.5 ) ^2
    die angle α The half angle in radians
    5 (Deg/180)*3.14156 typical 5-15 degree half angles
    D0 2.25 in
    D1 2.20 in
    α 0.0872222 B12/180*3.14
     reduction γ 1 - (A1/Ao)
    A0 3.9740625 3.14 *$B$20*$B$20/4
    A1 3.7994 3.14 *$B$21*$B$21/4
    γ 0.0439506 1-($B$18/$B$17)
     Δ 7.7627778 ( α rad/γ)*(1+(1-γ)^.5 ) ^2
    Minumum draw stress  Δmin =4.9(μ / (LN(1/(1-γ))))^.5
    coefficient of friction μ
    μ 0.11 guess
     Δmin 7.6656377
    draw stress σd
     avg flow stress σa average work per volume
    Yield Strength σy psi
    actual ys 200,000 lb/in*in
    drawing stress ratio Σ [(3.2/Δ )+0.9](α+ μ)         Another Book 5.13
    σd σy * (3.2/ Δ ) + 0.9)  (α+ μ)
    psi Draw Stress     572,776 $B$38 * (3.2/($B$24 + 0.9)) * ($B$16+ $B$33)
    Pounds Force  Stress * Area  572,776 * 3.799
    Force  2,176,205 =$B$41 * $B$19
    Draw Bench is called 100,000 pound?

    Can the Actual tested Yield be used in these calculations?

    Where do find where my math went wrong?



    ------------------------------
    David Kirchner
    COO
    High Performance Alloys, Inc
    Tipton IN
    (765) 945-8230
    ------------------------------

    Attachment(s)

    xlsx
    Metal_HB_14v9.xlsx   24 KB 1 version


  • 2.  RE: Draw Bench math

    Posted 12-15-2023 07:35
    David,

    Are you really drawing a 2.25 inch diameter bar down to 2.20 inches?! That is very large material, but a very light reduction (<5% RA).


    Dave Coulston





  • 3.  RE: Draw Bench math

    Posted 12-15-2023 09:53

    The context I was writing yesterday looked good to me, but it see now it did not flow well to this formatting.

    I am looking to find out how to apply mechanical engineering math to my draw bench. While some engineers are trying to get humans to Mars, I am trying to help by cold drawing to the next level.  This data was recorded from testing done till the carriage grip broke. Now I am slowing down and checking the math.  Input was a highly cold worked stainless at 2.25" diameter and it was drawn to 2.20" diameter. This die was bought as FF RA15 6" 5° 2.200. The 5° may be the full angle, not the half angle.

    Testing results:

    2.250" diameter 212 UTS, 193Yld, 17EL, 60RA Lot G4818

    2.220" diameter estimate 200Yld

    2.150" diameter 230UTS 210Yld 14EL 54EL 



    ------------------------------
    David Kirchner
    COO
    High Performance Alloys, Inc
    Tipton IN
    (765) 945-8230
    ------------------------------

    Original Message


  • 4.  RE: Draw Bench math

    Posted 12-15-2023 09:56

    The context I was writing yesterday looked good to me, but it see now it did not flow well to this formatting.

    I am looking to find out how to apply mechanical engineering math to my draw bench. While some engineers are trying to get humans to Mars, I am trying to help by cold drawing to the next level.  This data was recorded from testing done till the carriage grip broke. Now I am slowing down and checking the math.  Input was a highly cold worked stainless at 2.25" diameter and it was drawn to 2.20" diameter. This die was bought as FF RA15 6" 5° 2.200. The 5° may be the full angle, not the half angle.

    Testing results:

    2.250" diameter 212 UTS, 193Yld, 17EL, 60RA Lot G4818

    2.220" diameter estimate 200Yld

    2.150" diameter 230UTS 210Yld 14EL 54EL 



    ------------------------------
    David Kirchner
    COO
    High Performance Alloys, Inc
    Tipton IN
    (765) 945-8230
    ------------------------------

    Original Message


  • 5.  RE: Draw Bench math

    Posted 12-15-2023 09:13
    Edited by Scott Henry 12-15-2023 09:14

    Hi,

    For those seeking additional context, these equations are found in the following article in the current ASM Handbook series:

    Wire, Rod, and Tube Drawing, Metalworking: Bulk Forming, Vol 14A, ASM Handbook, Edited By S.L. Semiatin, ASM International, 2005, p 448–458, https://doi.org/10.31399/asm.hb.v14a.a0004008

    The relevant excerpt is shown in the image.



    ------------------------------
    Scott Henry
    Senior Content Engineer
    ASM International
    ------------------------------



  • 6.  RE: Draw Bench math

    Posted 12-15-2023 13:36

    David,

    I am a little bit confused by this calculation:

    σy * (3.2/ Δ ) + 0.9)  (α+ μ)

    I am probably not grabbing the right numbers... but when I plug values in, I get an answer that is about 1/10 of the 572,776 value you ended up with.

    Another Dave



    ------------------------------
    David Coulston
    Niles MI
    ------------------------------



  • 7.  RE: Draw Bench math

    Posted 12-15-2023 14:55

    In Excel I typed drawing stress formula as:

    σy * (3.2/( Δ  + 0.9))  (α+ μ)  = 572,776

    σy * ((3.2/ Δ ) + 0.9)  (α+ μ) = 51,760

    Draw Stress

                51,760

    $B$31 * (3.2/$B$21) + 0.9) * ($B$13+ $B$25)

    200,000 * 1.312 * .1972

    Pounds Force

     Draw Stress * Area

    51,760 * 3.799

    Draw Force

              196,657 lb

    =$B$40 * $B$17

    Thanks, you were right about the error.

    I have the updated 14A now, thanks Scott Henry.

    Can I use the actual Yield as the Average flow stress?



    ------------------------------
    David Kirchner
    COO
    High Performance Alloys, Inc
    Tipton IN
    (765) 945-8230
    ------------------------------

    Original Message


  • 8.  RE: Draw Bench math

    Posted 12-15-2023 16:58
    David,

    You ask a difficult question!

    As a ballpark number for Average Flow Stress, I would average the Yield Strengths and Tensile Strengths before and after drawing.


    Dave Coulston



    Original Message