Factors affecting bending of stainless steel? - Deformation Software? 1

[Hercules28]

Hi,

I have a machine that produces 90 degrees elbows from stainless austenitic steel tubes 304L. I have issues with the consistency of the bend angle. Do you have any idea why this would happen?

Any metal deformation software out there?

Which are the factors that affect the springback?
(grain size, thickness, cold work, deformation speed)?

Thanks

 

[Compositepro]

Download the Tube and Pipe Bending Manual here:

http://www.toolsforbending.com/literature.asp

 

[TVP]

There are several different software types for simulating metal deformation, including DEFORM from SFTC and QForm from Quantor.

DEFORM

http://Www.deform.com

QForm

http://www.qform3d.com/?go=main

 

[salmon2]

Second TVP on DEFORM, I used it for the similiar analysis before.

Spring back is a natural result of elastic recovery. So you need very accurate true flow curve of material for simulation.

Of course everything you listed is important. But grain size is hard to evaluate or monitor, it is a physical parameter, not mechanical. I want to say thickness, bending radius, punch stand-off are the primary parameters you ought to focus on. I assume this is a cold process, but sure you should avoid any cold work before this process. Deformation speed should be kept low, one punch several seconds is a reasonable speed to me.

If you want to do it very fast, you need flow curve at that strain rate for simulation too.

 

[Hercules28]

Thank you all. Your comments help me a lot!

 

[Hercules28]

Is there an ASM book for true flow curves for Stainless steels? (304L and 316L)

 

[salmon2]

Hercules28,

If you look down, you will see a thread I posted not long ago asking how to get true flow curve from a tensile test. I have done some reading and feel pretty good about it right now.

I suggest you get back with your tube manufacturer and hopefully get a full load/extension curve from a tensile test they did on your heat. Then I can help you to get the true flow curve out of it. Basically you can get very reliable true flow curve up to the necking poing; the translation after necking will be not so reliable because of localized strain, etc. Tensile data with round specimen are preferred. If your deformation does not exceed the uniform strain limit, which is the strain at necking onset, the simulation can be very accurate.

Or you may go ahead to do a tensile test, be sure to specify you want the total load/extension curve and round sample. This way, the data is a true representative of your material.

salmon2