[TheForge] warped 1" plate table

Mon Sep 2 00:55:00 2002

At 03:58 PM 9/1/02, you wrote:

Bob, Rick,Ray and Ralph;
  Gentlemen,thanks for your help!..I'll have at it again tomorrow. Like 
most of us, I'm a stubborn old  crusty.
In retrospect, new plate would have been cheaper of course..."The cheap guy 
pays the most" ,again.
It was difficult getting it to it's current location and , this being the 
"boonies"  heavy equipment resources are distant.

>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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