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Can I Flame Straighten 2'' Plate?


macbruce

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I have a piece of 2x30x50'' steel plate I'm going to use for a PH base and it has a 1/8'' bow in it the long way.........I do have a a large oxy propane (as big as a flamin' golf club) rosebud and am wondering if it's any use to try and get the bow out or just put the cup towards the floor and forget about it.............? thanks, mb

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Seems like flattening something that size in outside of an industrial setting would be difficult  to achieve with accuracy.   An alternate to flattening would to treat the machine base as a column base plate by using anchor bolts double nutted to level the machine and then grout solid under the the leveled plate.   I have seen column base plates more than twice that size successfully grouted.

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    do you know anyone with a lg Cat or track Ho ?? or the like -- 966 loader :) 

I have bent stuff this when needed also 966 is next door

put a block under each end steel would be better than wood, use cat blade to  press down on hump slowly ck often for straightness

to bend big stuff you need something Bigger

NOW other Idea put in forge bring up to temp and tap with hammer :o

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Hey Mac,

 

At the Bottom of this Site there is a # for Customer Service give them a call they will set you up to fasten that plat down to never come up for the PW and the force you are going to be giving the Bolts . and there is More then likely a "Hilti Rep" in the area that can even stop by to chat with you .

 

https://www.us.hilti.com/#0

 

I have used the Company a Ton of times .

 

Best Regards Brother Mac

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You can flame straighten it, but you need to read up on it a bit.  It is/was common on straightening steel plate in ship construction, where the plates were fairly thick.  Also, done in bridge construction.  Most used a rosebud with O/A.

 

I had several links on the subject bookmarked, but can't find them all.  I ran across one, here:

 

http://www.fhwa.dot.gov/bridge/steel/02.cfm

 

Same basic principle with plate.

 

You can google "heat straightening" and there is a lot of info out there.  Also, post messages on welding sites like weldingweb.com.  The link above did have some info on the patterns to heat and the size and type of rosebuds to use.  Basically, the area and side you heat will shrink when the metal cools.  

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straightened a round bale single fork for a neighbor after his kid stuck it in the dirt. Almost flipped the tractor. Heated it in my coal forge and had the old man press it down across my anvil with hydraulics. The loader with different hight blocks until it looks flat to you sounds good.

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MB do you have access to a heavy welding platen ?   If so you could place the crowned side down spaced above the platen with say a 1" square bar under the top of the crown and bolt the edges of the platen maybe using pipe sleeves welded to the opposing edges of the plate to provide the bending tension.  Then with bolts snugged, heat the concave side of the bend to allow a slow and controlled straightening a bit at a time.  Heat - measure - snug, heat - measure - snug.  Or measure, heat , snug.

 

My thought is that if you really want it flat the process needs a good flat, stable surface to work to, and the adjustment needs to be controlled incrementally.  

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MB, can it be done? Real easy if you know how! I used to employ a chap who could do it even with a hangover. Would it not be easier to just stick it in a shaper or mill? It would probably be fun(and expensive) to give it a bash, I would, at worst you would just machine it afterwards anyhow. I've got teak rail ties and rubber mat under my hammer so I'm not sure that a small bow would bother me.

Ian

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Greetings Mac,

 

A simple solution would be to slit a 1/8 cut the length about 1 1/4 deep and than heat the center at the 1/4 hinge .. If it corrects the crown gouge out a welding grove and stitch weld..  You do not need a lot of strength in the center if it is going to be a base..   Lots of big metal to work with...  Good luck..

 

Forge on and make beautiful things

Jim

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Torch heat the crown fast with no time to soak. The heat will expand the steel but there is too much resistance for it to move so when it cools it's been upset and draws. Drawing will pull the bow down. It's counter intuitive till you know how the steel moves.

 

Welding beads on the crown does exactly the same thing if a tad differently.

 

I have a plate hammer in the shop, think a long headed turning hammer in the 8l-10 lb range. It's for straightening plate but I have zero idea how. My uncle Frank would have known how, he was a welder in the Bremerton shipyards during WWII but I'm not psychic.

 

As I recall he called it "plate dressing" but that's a childhood memory, he may have been talking about Thanksgiving dinner.

 

Frosty The Lucky.

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You are basically looking to shrink one side. With a torch you heat it up, then quench one side which shrinks it drawing the other side up. I have seen pics of 6" thick plate several yards wide being heavily curved with heating, and cooling. What welding does is that as the weld bead cools it shrinks,and draws that side together causing a bend (warping).

Frosty, that hammer may have been used on the opposite side to spread it out, thus making the plate curve the opposite direction.

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Thanks all.........I've flame straightened many a beam and bar in my day but never tried a big thick plate.........If I can ever find my huge 3' long rosebud (I figure it's hiding in plain sight just laughing at me) that fits my Victor body I think I'll have a crack at by applying heat across the plate in about a 4'' swath  for say 15 minutes, let it cool and see if there is any improvement. With that torch, 15 minutes will equate to about half a large bottle of Ox but very little in propane by comparason.  If there's no improvement then I'll use it as is, being mindfull NOT to square off the plate and use the digital level to make the post and anvil paralell..........

   When I bought this plate I didn't check it for flat thinking/ assuming 2'' just HAS to be flat....right?..............Still learning,lol, but at .40 Per pound I probly would have bought it anyway................ B)

 

 

 

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I thought you were going to bolt your power hammer to this piece for added weight. I would weld the anvil to the crowned area up, the welds will help straighten the plate naturally.

No my old 220 lb'er was brought up to 10 to 1 some ago and it works just fine. This is a new 200lb hammer with a KZ control for a client. Of all the hammers I've made welding the mast and the anvil to the base plate never affected the plate so alignining the two will be a bit trickier.

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You are basically looking to shrink one side. With a torch you heat it up, then quench one side which shrinks it drawing the other side up. I have seen pics of 6" thick plate several yards wide being heavily curved with heating, and cooling. What welding does is that as the weld bead cools it shrinks,and draws that side together causing a bend (warping).

Frosty, that hammer may have been used on the opposite side to spread it out, thus making the plate curve the opposite direction.

 

 That makes intuitive sense Guns but I just don't know . . . maybe someone here does know how to use the thing. I'd sure like to know, that way if I ever get a chance I won't have to start from zippo.

 

Frosty The Lucky.

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I dont think that heating a  wide strip will work.

 

The way I do it, I think of it as a traveling spot. I would use an oxy torch start at one edge and heat a small spot almost to 1200F then work my way across the plate keeping the heated line reasonably thin (1.5-2 inch maybe) letting the metal cool behind the spot. You dont want the underside to get too hot or it wont work.

 

the idea is the cool steel in front of the heated area is holding the heated spot under tension and causing the upset in the hot metal that you need to make it move back as it cools. If you heat a whole strip at once it will just bend up and shrink back to its original shape.

 

Pretend you are welding it, but with the oxy torch.

 

edit 1200F is not that hot, it is a silvery look after the torch has been removed for about 5 seconds in average daylight. So dark red in good daylight is a little hot for heat shrinking. that is the best I can describe it, sorry!

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I ran the biggest oxy-propane rosebud I could find across the hump(still can't find my monster) for about a half hour today and It did move the metal, making the hump worse by about a qtr inch which is what you want when it's hot..........If all goes well it should shrink back more than it expanded......We'll see in the morning..........

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Everytime I have flame straightened a plate I immediately quenched the hot side to shrink it. I have watched bent conveyor side plates move inches as the wet rags hit them. Thick plate might need a hose, but I think it would work much better than air cooling.

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Only a slight inprovement when I checked it this morning...............What I really need is my monster torch which is still in hiding :( Maybe I can borrow one as a new one will set me back around $300.

Believe I will quench it next time with my trusty siphon sprayer when I get my hands on a bigger rosebud......

I've watched guys use these along with local heats to straighten/curve beams that weighed 400 lbs per ft without flooding the shop with water....

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