600 deg C is about the right temp for stress relieving mild steel so the oven is out, barbeque will do it but not sure how you monitor the actual temperature?

To prevent scaling the part can be placed in an airtight tin or wrapped in stainless steel foil with something combustible to burn off the oxygen.

Tony

Stewart,

Mentioned this recently on another thread – but don't be tempted to use kitchen foil – it will melt.

I know!

IanT

There was a thread about cast iron 'chill' – and it's treatment recently Stewart. Not the same problem I know but perhaps a similar solution.

https://www.model-engineer.co.uk/forums/postings.asp?th=138364

I've placed both suspect castings and mild steel in my incinerator overnight to help with these things. I won't repeat everything again (as it's all in the previous thread) but I do feel it helps…. but I would also do a wee bit of roughing first too

Regards,

IanT

I would get out the propane torch and heat it up to a good red heat, keep it there for a while, and then let it cool as slowly as possible. A few chunks of firebricks around it to make a rudimentary furnace would help keep the drafts off. There will be some scale but not as much as with the old way of putting it in the embers of the fire overnight. There is very little danger of accidently getting it too hot, you won't melt it with anything you are likely to have at home.

If you don't have a propane torch, it is a really worthwhile thing to acquire, since you can also use it to harden bits of silver steel, or drill rod if you like. (or gauge plate.)

John

Hello Ian, I thought that treatment was for hardening? Do you not want a slow cooling for stress relief? Quite happy to be shot down over this as the memory is not too sharp these days.

Andrew.