All About The Heat I Guess - Page 2
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  1. #26
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    Aug 2008
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    Re: All About The Heat I Guess

    Quote Originally Posted by cd19 View Post
    Do you see the contradiction? If peening works like you said to relieve stress in the weld, then heating the backside and shrinking it hardly relieves stress in the piece, it adds stress. Although the weld may permanently bend a small area, it doesn't permanently bend the whole piece. I don't take away that it works, I just don't think it is always the best solution.
    You're partially right, and I'm partially wrong. There is some residual stress from flame straightening.

    http://shipstructure.org/pdf/198.pdf
    http://www.shipstructure.org/pdf/247.pdf

    However, the Fed Highway Admin. accepts this form or repair.
    https://www.fhwa.dot.gov/bridge/steel/heat_guide.pdf

    Given the alternative...….a totally useless piece of metal......some stress is acceptable.

    PEENING


    Sounds really great. Has a nice ring to it......but is it the answer?????

    Peening is a cold working process...……...In other words...…...it's after the fact. The damage has already been done. Once you exceed the tensile strength of the parent metal, it's a done deal. The warpage/bend is permanent. There's been deformation.

    Real world...….tack a piece of metal to something. The first tack causes the piece to rock back towards the tack. The second tack snugs it up, but has caused some movement in the parent metal.

    First weld when the assembly is still hinged (free to move). Name:  weld distortion1.jpg
Views: 252
Size:  137.2 KB

    Name:  weld distortion2.jpg
Views: 253
Size:  133.6 KB

    No distortion. Name:  weld distortion3.jpg
Views: 251
Size:  116.5 KB

  2. #27
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    Re: All About The Heat I Guess

    So now, let's tie that baby down.

    Second weld. Name:  weld distortion5.jpg
Views: 248
Size:  123.1 KB

    We gotta problem. Name:  weld distortion6.jpg
Views: 246
Size:  137.6 KB

    So, taking the argument in hand, let's relieve the stress in the weld throat. Name:  weld distortion7.jpg
Views: 248
Size:  124.9 KB

    Cutting the weld relieves all stress wouldn't ya say?

    Now lookee what we got. Name:  weld distortion8.jpg
Views: 250
Size:  130.8 KB

    You can beat the livin' ****e outta that weld, and it ain't gonna correct the permanent distortion.

  3. #28
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    Aug 2008
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    Re: All About The Heat I Guess

    So, you gotta choice. Change some things, or live with an obviously ruined weldment.

    I noticed that they say that straightening is an art. I agree. And I truly believe I'm an artist. I try to pass this stuff on at every chance I get. I'd like others to try it, and develop their own skills

  4. #29
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    Re: All About The Heat I Guess

    Artist...…..sounds arrogant...….well Hell, just had a doood tell me I'm arrogant, and ignorant...…...might as well fit the profile

  5. #30
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    Aug 2008
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    Re: All About The Heat I Guess

    STRESS RELIEF

    If you have an oven big enough, be my guest. Have to elevate the temp to around 1100 degrees, hold it for a soak period, then cool it at a controlled rate. This is simply unfeasible in a shop environment.

  6. #31
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    May 2008
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    Orange, TX
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    Re: All About The Heat I Guess

    Quote Originally Posted by farmersamm View Post
    Yeah, and my stupid push mower won't start The mower K'kins uses is too low to mow the shop. Never know what's under all that tall Johnson Grass.
    Goats Samm. Getcha some dem goats.
    MM200 w/Spoolmatic 1
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    Save Second Base!

  7. #32
    Join Date
    Dec 2015
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    Kentucky
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    275

    Re: All About The Heat I Guess

    They would eat he flowers and some weeds and skip the Johnson grass.
    Round up early and often
    Mike

  8. #33
    Join Date
    Dec 2010
    Posts
    558

    Re: All About The Heat I Guess

    Quote Originally Posted by farmersamm View Post
    So now, let's tie that baby down.

    Second weld. Name:  weld distortion5.jpg
Views: 248
Size:  123.1 KB

    We gotta problem. Name:  weld distortion6.jpg
Views: 246
Size:  137.6 KB

    So, taking the argument in hand, let's relieve the stress in the weld throat. Name:  weld distortion7.jpg
Views: 248
Size:  124.9 KB

    Cutting the weld relieves all stress wouldn't ya say?

    Now lookee what we got. Name:  weld distortion8.jpg
Views: 250
Size:  130.8 KB

    You can beat the livin' ****e outta that weld, and it ain't gonna correct the permanent distortion.
    I would not agree that cutting the weld relieves all the stress, there is a fair amount of stress in the weld itself. As far as flame straightening being an approved REPAIR procedure, that I have no problem with, however on something that was bent for example you are using the heat shrinking to shrink the stretched metal. In a new piece I'd rather deal with the stress where it is actually coming from.

  9. #34
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    Aug 2008
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    11,095

    Re: All About The Heat I Guess

    Doing all my final "heavy" welds today. I like to do anything involving heavier plate with the Ranger. It has more oomph than the little crackerbox, and it's infinitely adjustable, which is a real plus when going uphill. Plus, when I can, I like to run the Ranger for as many welds as possible in a short time.....less gasoline, and like me,, it ain't gettin' any younger

    Name:  heavy duty hinges52.jpg
Views: 131
Size:  134.5 KB You can see a lot of arc blow on this side of the hyd cylinder tab. Always fighting arc blow

    Name:  heavy duty hinges51.jpg
Views: 132
Size:  124.3 KB This side had no arc blow, and the flat weld came out nice and clean.

    The flat welds are 5/32 Excalibur at just shy of 180amps. The uphills are 1/8 at around 8.5ish on the 130amp range.

    After these are complete (few more passes to go), the heat input will entirely surround this piece of tubing...….which should have a neutral effect on distortion. All things being equal I gots 1/2" hinges, 1" plate, and an adjoining piece of 3/16 wall tubing...…...all converging at this point If this pulls, it's gonna be an epic straightening mess

  10. #35
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    Aug 2008
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    Re: All About The Heat I Guess

    BTW......I have a bit of a preheat on the 1". Ran it up to around 300 degrees, which is high, but by the time I get around to moving stuff where it's supposed to be, grinding out the tack welds, etc...…….it's back down to around maybe somewhere shy of 200.

    Name:  heavy duty hinges53.jpg
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    It's all there in the "Bible" Great little book.

    Now theoretically...….preheat is gonna keep my welds from cracking as they cool (preheat makes for slower cooling), and it sometimes helps with reducing distortion.

    How can the welds crack?? This is a sort of restrained weld. There's no give to speak of in the 1" plate, although the 3/16 tubing is fairly flexible. I'd rather cover my bets, and put some heat to it before gluing it up.

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