Steel memory
Steel memory
(OP)
Hi all,
Wondering if someone can help.
If you can picture a strip of steel about 6mm wide x 1-2mm thick x 250mm long.
It is flat half way along(125mm)and then curves down at a constant radius like a quadrant of a circle.
Now that needs to be the original shape of it.
What I need to do is insert it (quadrant end first) through a straight tube (16mm bore x 200mm long)
So it needs to be flexible enough to almost flatten out to go through the tube and come out the other end returning to original shape.
I hope this is understandable.
I need to know what spec steel to use and if or what heat treatment is needed.
Wondering if someone can help.
If you can picture a strip of steel about 6mm wide x 1-2mm thick x 250mm long.
It is flat half way along(125mm)and then curves down at a constant radius like a quadrant of a circle.
Now that needs to be the original shape of it.
What I need to do is insert it (quadrant end first) through a straight tube (16mm bore x 200mm long)
So it needs to be flexible enough to almost flatten out to go through the tube and come out the other end returning to original shape.
I hope this is understandable.
I need to know what spec steel to use and if or what heat treatment is needed.





RE: Steel memory
Why do you think you need heat treatment?
RE: Steel memory
Think of it this way, if you have a flat part and bend it in this radius would you expect it to spring right back straight?
Calculate the stress involved, and then we can see if this is even possible.
You would be helped with a material with a lower modulus (Ti, Al, Cu, Mg) and very high strength (steel, Ni alloys, Ti alloys, BeCu), and making the part thinner (to reduce stress).
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Steel memory
RE: Steel memory
I have tried to attach a sketch, hopefully it has uploaded OK.
Basically the metal strip that can be less than 1mm thick if it has to be, needs forming to the shape on left of picture.
It needs to flex to push through tube (right in pic)and then return to formed shape (left of pic) when it comes out.
Please note that the scale of picture is not perfect.
RE: Steel memory
What prevents you from inserting the metal strip from the straight end?
Design for RELIABILITY, manufacturability, and maintainability
RE: Steel memory
https://res.cloudinary.com/engineering-com/image/upload/v1451335800/tips/inserted_up_to_bend_1mm_oif8j9.pdf
Once you pull the straight end of you part through to the end of the pipe your centerline radius will have to flatten to 141.64mm radius (provided bend flattens uniformly
https://res.cloudinary.com/engineering-com/image/upload/v1451335934/tips/pulled_through_to_end_of_pipe_1mm_gklm29.pdf
Then once the entire rolled section is in the pipe it will have flattened the radius even more to a 268.12mm radius
https://res.cloudinary.com/engineering-com/image/upload/v1451336060/tips/roll_pulled_just_into_pipe_1mm_o4dtlk.pdf
I realize this doesn't give you the material but it does you you’re geometry change that your part will need to experience during this pull through operation
RE: Steel memory
djhurayt, that is what the metal strip needs to do, thank you for taking the time to create the drawing.
Any ideas? can it be done? or will I need to resort to a different metal or different material; ie fibreglass, plastic....?
RE: Steel memory
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Steel memory
http://www.mscdirect.com/browse/tn/Motion-Control-...
This is a strain based issue so what Ed Stainless said about modulus of elasticity is the only property you are concerned with along with thickness. Modulus of elasticity will not change with heat treatment but yield strength determines how tight of radius you can bend before permanent deflection occurs,
DESIGNER: You said, "Basically the metal strip that can be less than 1mm thick if it has to be, needs forming to the shape on left of picture."
Design for RELIABILITY, manufacturability, and maintainability
RE: Steel memory
Design for RELIABILITY, manufacturability, and maintainability