A question about ASTM A513 pipe

[Rustybolt]

The set up; I have some 3.5 inch Dia. by .500 wall thickness 513 pipe I need to machine into fixures. Part of the maching will require that I mill a slot nearly the length of the piece.
The questio; Do I need to stress relieve this stuff first? I don't want the slot to spring open.
Thanks guys.

[Toolguy]

I would. You don't know which way it will go. It may spring shut and clamp the saw blade. That is worse - it may break the blade.

[CCWKen]

Depends on the type. Does it show any signs of scale or made from hot rolled (generally a rough surface)? If not, relieve.

[Rustybolt]

Its cold formed DOM.
I'm just going to be on the safe side and have it stress relieved. It's not my money and the boss didn't flinch when I told him the project might be a couple of days late.
Thanks guys.

[JoeLee]

You never know what may happen when you cut into rolled products. I would try one and see.

JL......................

[Rustybolt]

Joe the reason I don't want to try it is that the equipment I'm working with isn't mine and I don't know what kind of stresses are built up in a piece of cold formed tube with .500 wall thickness.
If it decided to spring apart it could ruin my day not to mention the tooling.

[RichR]

Couldn't you make a close fitting plug, mill your slot, pop out the plug, and take a cleanup pass?

[JoeLee]

Joe the reason I don't want to try it is that the equipment I'm working with isn't mine and I don't know what kind of stresses are built up in a piece of cold formed tube with .500 wall thickness.
If it decided to spring apart it could ruin my day not to mention the tooling.

Understood. You could cut it most of the way on a horizontal cut off saw and then lock it in a vise and finish cutting through by hand, then release it and see what happens. I've done this with 2" square tube .375 wall. The square tube I cut opened up just over 1/4" when I broke through.

JL................

[darryl]

I think it's fair to say it will spring. Ordinary pipe would spring open, not sure about DOM. You'll probably have to look at it in terms of how critical the final shape and dimensions are to be. You can take material off the OD without distorting it much, but a slot is going to screw with it. If the slot needs parallel sides, you'll have to open up the length of it first, then machine it to the spec.