Steel pipe questions

[Slauma]

If a weld is done is it possible to re-temper the entire piece? If you bring it to the right temperature and hold it there it will anneal right? How hard would that be to do?

[Moonbogg]

If a weld is done is it possible to re-temper the entire piece? If you bring it to the right temperature and hold it there it will anneal right? How hard would that be to do?

I did that with a cannon made of aluminum. Using 4043 filler rod is common for post weld heat treatment. This rod anodizes to a jet black color, so if your part is anodized, the rod may stand out, but its a small price to pay to regain tensile properties lost during the weld process. I read somewhere it is not guaranteed to regain 100% of the base metals strength, although much of it will be regained. So make sure your safety factor is as high as possible.

[jhalek90]

Umm.... schedule 40 steel thats only rated to 400 psi????
WHAT?

My pneumatic steel 1'' valve has been used at like... 850. (CO2)
But than again... that is only 1'' 2" would be considerably weaker assuming the same wall thickness.

On a side note, they do rate the pipes and fitting on the low side. i would not put a steel fitting being pushed past its rating by MY face... but you would also probabbly be fine if you overshoot the pressure rating by a tiny amount, not alot... but a little should be okay. If your comfortable with that.

And again... i have very little experience with combustion cannons...im talking from pneumatic experience .