sheet metal forming

[danielanarine]

hi all!

Can anyone tell me what the smallest diameter that can be achieved by rolling a 1/16" thick metal sheet?

Thank You! :->

 

[finman]

The smallest diameter will be dependant on what the material is and the application the final ring or tube is put to.

On stress bearing components in mild steel I use the following; bend radius = 2 x the material thickness, however I have used 1 x the material thickness for a 180 degree, none structural component.

But you must satisfy yourself that this will work for your problem.

The question has to be asked, why not use small dia tube and cut it to length? this is probably better from a stress and accuracy point of view.

 

[borjame]

finman is correct that the bend radius is a function of material and heat treat, 1T should be the lowest but you'll need to check with a materials handbook or a materials engineer familiar with the metal.

 

[arto]

For reference, the ASME B&PV Code UCS-79 [carbon steel] lets you go up to 40% extreme fiber elongation in some cases.

Percent Extreme fiber Elongation in defined as:
50t[1-Rf/Ro]/Rf for single curvature [i.e., cylinders] &
75t[1-Rf/Ro]/Rf for double curvature [i.e., heads]

t = Plate thickness
Rf = final centerline radius
R0 = original centerline radius [infinite for flat plate]

You probably would want to dye check for cracks, too.

 

[limct]

For sheet metal bending, directionality of sheet or strip metal is a factor which must be considered in relation to bending, the most favorable considtion exists when the axis of the bend is perpendicular to the grain direction. Of course the hardness does play a major role.

1) quarter hard temper, and bending axis MUST be perpendicular to the grain direction and (bending radius >= stock thickness) , for this material to be bent parallel to the grain size, it's advisable to maintain at 90 degree right angle the most.

2) Skin rolled temper, basically a grade which is suitable for fairly deep drawing operations where surface disturbances such as stretcher strains are objectionable. It cane be bent in direction.

3) dead soft temper, a very soft and ductile cold rolled strip, it is suitable for bending flat upon itself in any direction.