Back end defect- coring

  • Thread starter yaver
  • Start date
  • #1
yaver
2
0
Hello,
I'm learning about the phenomenon of coring (back end defect) during the process of aluminium extrusion. I try to find a solution to this problem.
Is there anyone who know how can I prevent or even reduce this problem from the extrusion process
thanks
Yaver
 

Answers and Replies

  • #2
PerennialII
Science Advisor
Gold Member
901
1
Do you mean a some sort of a limit forming problem ?
 
  • #3
Astronuc
Staff Emeritus
Science Advisor
20,851
4,804
Coring (or coning or piping) is usually a front end problem in the extrusion of round barstock from round billets, and it is usually a problem with softer metals. I am somewhat familiar with this problem because it resulted in some defective barstock which led to product failures in the field.

The problems arises because there is a huge gradient in the hydrostatic and shear stresses at the front face of billet that is extruded through a die, and perhaps increases as the billet diameter increases in comparison to the die hole diameter. Perhaps a similar problem exists at the back end.

Also die lubrication might be an issue.

Adding a disk of softer material (Al) between the billet and mandrel might help.

But then one needs to cut off the Al portion at the back end.
 

Suggested for: Back end defect- coring

  • Last Post
Replies
3
Views
1K
Replies
1
Views
3K
Replies
1
Views
3K
Replies
3
Views
1K
Replies
6
Views
3K
Replies
1
Views
3K
  • Last Post
Replies
3
Views
2K
Replies
1
Views
3K
Top