316ss, hot forming

[Hitch]

Need to get some bends in 25mm diameter bar, no problem, except some of them will probably need to be done hot to avoid damaging the cross section of the bar where its under pressure from the tooling.

The finished parts will be subject to various tests, including a magnetic test, will heating the bar give me problems with magnetism?

Once formed, the parts will be cut, welded, ground, and polished.

 

[hotrodder]

Heating won't give you problems, cold forming probably will. Annealing will deal with any magnetic issues from work hardening etc

 

[TechnicAl]

remember that annealing 316 involves quenching...........its the opposite to what most people think about annealing

 

[Welderpaul]

What's the job?

 

[madkayaker]

Stainless chain?

 

[Hitch]

I can press them while they are hot, which will dramatically reduce the forces for bending, stopping the indents from the rollers on the tooling.

Al, do you mean, once the bends are formed, annealing them again will reduce the magnetism levels?

On the other hand, the formed parts will also be subject to load testing, only about 3t, but another consideration.

 

[TechnicAl]

as Hotrodder says cold working increases the magnetism

softening (annealing) will return the ferrite to the inherant level.........probably less than 5FN.........depends

 

[Hitch]

From memory, I think the testing will be carried out in numerous places, something along the lines of a reading of 1.10 maximum....how and what its measured in, i have no idea.

 

[TechnicAl]

1.10 doesnt sound right..........doesnt ring any bells

 

[hotrodder]

Al, is that because you'd normally be concerned about/work in ferrite numbers or does it sound wrong for a measurement of relative magnetic permeabilty (something to do oersteds, maybe 200 of 'em i think )?

Forgot the link... http://www.sandmeyersteel.com/304.html#4 should goto physical properties, link's for 304 as under 316/316L it just said something along the lines of 'typically less than 1.02 in the annealed condition'

 

[TechnicAl]

Looks like thats it

I dont think Ive ever seen those numbers before. Do you know how they measure it?

 

[hotrodder]

Dunno but there appears to be several methods. Found a pdf of the ASTM standard... http://wenku.baidu.com/view/69e0680ef12d2af90242e61a.html and this gizmo... http://www.severnengineering.com/lomu.htm