[TheForge] warped 1" plate table

Sun Sep 1 18:08:02 2002

Try to keep the side opposite to where you are heating cool with an
air-water spray. Make a siphon out of a plumbing tee ,water coming in the
bottom, air in one side and the air- water spray out the other. If you can
get half  the thickness hot rather than the full thickness, you will get a
better pull. As Ray said- shrink the high side. Actually the pull comes from
an upsetting effect- the cold surrounding material will prevent the
expansion in that direction and the material will get thicker where you heat
it.  When the cooling occurs the surface area is smaller so that area will
shrink.
 Bud Oggier told a story of shipyard work where they got a warped deck plate
hot with big torches. he then used fire hoses to cool the area around the
heated zone. When cold a 2 inch high "pimple " formed that was cut off to
get the deck level again. That was the result of the upsetting effect.
 Another way to level plate is to roll it in pinch type rolls. Put a radius
in it, turn it over and roll it flat. The extra metal winds up at the edges.
This may be hard to do with 1" plate.
 Steel plate is very cheap now , have you considered buying a new piece? Bob
----- Original Message -----
From: "Peter Fels and Phoebe Palmer" <[email protected]>
To: <[email protected]>
Sent: Saturday, August 31, 2002 11:03 PM
Subject: [TheForge] warped 1" plate table


> I'm in over my head again and wish to beg some of you-all's expertese.
> This 1"x8'x9' plate is warped and while I've been able to
> herd  the  warpage around, I've been unable to get it flat.
> It is up on house jacks in the work yard and presently has a gentle
> diagonal crease about 3' long  so the thing is high on 2 corners.
> The theory I had was that by spot heating and quenching, it would shrink a
> little at that spot and that if a line was heated and quenched,it would
> shrink along  the length of that line.
> What seems to be happening instead is that the spot heated area bulges and
> only partially returns to flat when quenched and that the heated line
seems
> to  cause a folding  along the line that draws the sides up perpendicular
> to the heated line.
> So the theory is wrong.
> Would someone be so kind as to explain this  and how to control it and fix
> the problem..or where to find the info?....thanks...Pete F
>
>
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