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Steel plate types

Discussion in 'Center Of Gravity' started by bigjbear, Mar 17, 2004.

  1. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    First, if this is not the right place move the thread, no explanation needed.

    Now for the meat of the post. When plate needs to be bent are there different grades of steel to use? My "?" comes from looking at a lot of plate and seeing how porous it is. When something in the 1/4" range is bent at a 90* angle does it created stress rises that would lead to possible cracking when put under a heavy load? Is there a certain type/grade that lends itself better to being bent. The intended use is for an 8274 mount.
     
  2. Muddytazz

    Muddytazz 1 ton status

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    I don't have an answer to your question, but was thinking about that when I made my 8274 mount 2 yrs ago. I just got myself a piece of 10" x 10" x .500 square tube and turned it into a piece of angle plate(the remnanent yard didn't have any angle iron that big).
     
  3. ZZ4x4

    ZZ4x4 1/2 ton status

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    In my experience with plate steel, it would probably be fine to bend 90 degrees in a brake with minimal risk of cracking at the bend. I know plenty of winch mounts and bumpers which are manufactured this way. However, I still prefer to make a line cut (but not all the way through )with a metal cutting blade and my circular saw. Then I bend the plate at the cut and put in a weld seam down the length of the bend. This hardens the bend and thickens the area.

    I still think 1/4 inch might be too thin for a winch mount though. Might want to consider using a C channel , maybe 8 inches wide?? /forums/images/graemlins/thinking.gif
    Good luck
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Looks like a fine CoG discussion to me. /forums/images/graemlins/waytogo.gif

    Even on an 8274 (assuming a proper vertical mount) 1/4" is borderline IMO. I think I would rather go 3/8 unless your planning a vertical rib or something near the bearing plate bolts.

    Not sure on the grades, I'll leave that to someone else (and eagerly await the answers).

    As already suggested, I generally slit and weld. One word of warning though. Not too long ago I got a plasma cutter. A few weeks ago I needed to build a skid plate with some bends. Not having a press brake, the only option was to slit and weld. So, I got the bright idea to use the plasma cutter to make the slit. Basically just speed up the travel for 1/2 inch or so every 3 inches so that it does not completely pierce in those areas. Bend as desired in a make shift press and weld it up. But I overlooked 1 problem (that some of you have probably already pegged)... The plasma cut is oxidized, so the weld was really crappy. And of course it was late the night before a run so I really didn't feel like grinding it all clean and welding up a huge gap. So there it sets on the truggy, crappy welds and all.
     
  5. jjlaughner

    jjlaughner 3/4 ton status

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    [ QUOTE ]
    I still prefer to make a line cut (but not all the way through )with a metal cutting blade and my circular saw. Then I bend the plate at the cut and put in a weld seam down the length of the bend. This hardens the bend and thickens the area.

    [/ QUOTE ]

    So is the cut to the inside of the bend?
    [​IMG] Like this?

    I have no idea on plate types /forums/images/graemlins/dunno.gif But I'm thinking a cold rolled would be stronger but more likely to crack becaues of the density. Biggest metal I have delt with is 3/8.

    My best guess would be to do the cut (on top) and lightly heat the back side along the seam to get the metal to expand /forums/images/graemlins/thinking.gif Sounds good anyways /forums/images/graemlins/tongue.gif
     
  6. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I bend it the other way. Cut to the outside. That gives you a nice trough to weld for full penetration and strength. No heating required if you get the cut deep enough. I usually set up a make shift press or use my 12 lb sledge, and sometimes it's as easy as bending it by hand...
     
  7. ZZ4x4

    ZZ4x4 1/2 ton status

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    Yup, same as BadDog. I bend the other way for a nice trough to weld in. Seems like there could be voids if I welded on the inside corner, plus I'm not sure the cut is wide enough to allow a 90 degree bend before the edges hit each other. /forums/images/graemlins/thinking.gif For a slight bend, either way may work.
    jeff
     
  8. Butch

    Butch 1/2 ton status

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    You would want to use A36, or mild carbon steel for something like that. Something to be aware of is steel does have a grain just like wood. Flat bar can be bent across the width, but not up the length as it will crack at the ends if bent to 90 degrees cold.
    Whereas plate steel, IE 4x8 sheets can be bent across the length, but not so much the width. This will vary with different properties of the metal, so it is kind of a rule of thumb.
     
  9. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    [ QUOTE ]
    However, I still prefer to make a line cut (but not all the way through )with a metal cutting blade and my circular saw.

    [/ QUOTE ]
    That will be what I do unless I can get my brother-in-law to bend it for me at work. It sounds a lot easier than doing it the heat & hammer way.
     
  10. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Russ I was planning to brace the ends of the formed angle with 1 3/4, .120 wall tube mounted at a 45* angle. I first I thought this would be plenty, but maybe I have overestimated the strength of the plate??? 3/8 seems like overkill???, max load would be 16k lbs if double lined on the last layer. I am going to have to think about this some more. Anyone have a source for figguring what loads plate can handle? Or better yet personal experience w/ overloaded plate failing?
     
  11. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Thanks Butch. Can one look for the grain in a cut piece of steel? Or is just a matter of L vs W?
     
  12. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Simple load calcs on the plate are going to be dependent on the moment arm, which will be the length between the bolts holding down the bearing plates, and whatever is holding the plate in place. But other parts of the structure are going to influence this depending on the overall design, and that can get much more complicated but much more accurate. Bottom line, if the structure holding the vertical plate vertical is fairly close to where the winch bearing plates bolt down and supports the full length of the bearing plate, then 1/4 is just fine. But, if that support is say 3" to either side, then you may be bending the plate on a hard pull with ¼ HR. But ¼ CR might be fine, or some alloy, etc. Rough guesses, I don't have the info to run real numbers.

    As for AR plate, that’s cool for skid plates, but it can be a real pain to cut or weld depending on your access to equipment and skills. I'll probably be doing my next skid in AR, but I had the 1/4 HR lying around so... the rest is history...
     
  13. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Hmmm, to be more specific, if the vertical front plate is solidly attached to the horizontal base plate (i.e. fully welded), and the winch is mounted as low as possible on the vertical plate, and the 45* angle braces (gussets) tie into the vertical plate near the top of the bearing plate on each side, then 1/4" HR plate should be fine.

    In fact, I would just make the angle gussets out of 1/4" plate and fully weld to the base plate and vertical plate as close as I could get it to the bearing plates without interfering with the winch operation. I think this would hold up fine as long as the whole thing tied into the frame rails adequately.

    But again, this is all just "shooting from the hip" since I don't have actual numbers.
     
  14. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    I thought about using plate for the gusset angles and depending on how I mount the whole thing I still might. The current plan is still for tube but I may add triangle plate gussets to fill in the space between the tube & the angle. If go any further in my description this will turn in to a "bumper" post.
    Cutting will not be a problem. Most of it will be done on a large shear. I have the capacity to weld the thicker plate, I just wasn't sure it was needed. Thanks for the input, I've got a plan now. I'll be talking w/ my steel guy Monday /forums/images/graemlins/thumb.gif
     

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