Hi,
there is a wrinkle to stress relief. For centuries thermal stress relief has been the norm, but raising a steel or iron part to 6500C letting it soak and then slowly cooling it over a period of 24 hours or so
requires a s***t ton of heat.

There is another technique called Vibratory Stress Relief. It's a machine that shakes the bejesus out of the part with a variable frequency. Its way WAY cheaper. There is quite a lot of papers about its
effectiveness in the academic record. It seems to work well with large structures but is less effective with thin sections, so the jury is out with regard to welded steel structures with thin sections, say 1/2 inch or
thinner. For such structures thermal stress relief is still the way to go.

My cast iron axis beds were vibratory stress relieved, the company that did the machining have such a machine and use it themselves, and it cost about $300NZD to have three cast iron beds of 115kg each
done. Had I got then thermal stress relieved it would have cost $2000NZD.

If you are looking to weld a structure the vibratory stress relief might save you a swag of money. It did for me....mind you the thinnest part of my axis beds is 50mm, so the technique is known to work well with
parts of that type.

Craig