Hello,
We are manufacturers drawn bars. Currently we draw: Round , Hex and Square shapes. I needed some information about drawing other shapes/profiles that are specific to various customers. Apart from making the die, are there any special procedures that may be required? Profile/Shape rolling? Aneeling?
If anyone has any information, I would really appreciate it if you could share it with me.
Thank you, Sachin
Dear Sachin,
The input shape (cross section) must be as close as possible to the finished shape's cross section. For example drawing a "half circle" profile is best done with oversized round milled one one side or as a as-rolled to oversized "half circle" stock. Theorectically, you can drawn a "half moon" cross section from an oversize round (full circle cross section) using several dies morphing into a half moon cross section - with intermediate stress relieving (or re-crystallization anneal) between the draws.
A cold finishing mill in Indiana once had a small re-roll hot mill on-site to make special as-rolled shapes from purchased hot roll (straight) rods of basic round, square, hexagon, or flats.
Cold finishing difficult shapes by drawing requires heavy drafts (or draughts as the British say) with intermediate thermal treatments keep to a minimum due to cost. Some cross sections as "I" beams are never cold drawn because straightening after drawing is problematic and requires some acceptance in loss of some desired quality due to redundant deformation.
Ed Vojack
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