Re: sourcing - steel vs aluminum - stree relieving

--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

> Stress relieving is an annealing process that normalizes a

weldment. When materials are welded, heated to high temperatures
unevenly they distort and contain stresses in different areas. This
includes stamped and cold formed parts as well. Annealing involves
placing the weldment in an oven and taking it up to temperature to
allow the molecules to flow evenly then the part is cooled slowly
allowing the molecules in the steel to properly align themselves
evenly throughout the weldment therby alleviating all stresses
produced by welding. It's the opposite of heat treating which carbon
steels are taken to a specific temperatures depending on the rockwell
desired and as the molecules flow the part is quenched in oil or
water thereby abrubtly halting the flow of the molecules. Not
allowing the molecules to re-align themselves and making the part
brittle/hard. A note on stress relieving for general purpose
welments: Don't waste your money.

>
> Ron
>

I looked in the yellow pages and found a couple guys in Philadelphia
who do that type of work. As far as I know, it is best taken to a
show who has the ovens and ability to control temperatures.

Also, make sure everything is firmly fixed in place. if you have a
leg that is up in the air with weight on one side, it may actually
lean over when it comes back. the temperature gets the metal to the
point of (hope I'm using the correct word here) placiticy ? The
stress from the weight will allow the leg to actually bend.

If you grind the top flat you may get a very flat result. if you
leave in a weld bump in the middle of the table so the table rocks on
it, the table will bend.

Dave