Material Engineering - Metal Forming & Welding

  • Thread starter hafiz88a
  • Start date
  • #1
1
0

Homework Statement



Lightweight bicycle had been fabricated from aluminium alloy tubing, with joints made by adhesive bonding. When the frame fractured near one of the joints, the owner requested that a repair be made using conventional gas tungsten arc welding. Shortly thereafter, the frame broke again. This time the fracture was adjacent to the repair weld and the the characteristics of the break were different. The first fracture was somewhat brittle in nature, the second fracture occurred in the tube material, not the weld itself.

Homework Equations



If the material had been cold drawn aluminium tubing (i.e. strain hardened), explain what might occurred during repair. What is the possible cause of the second fracture?

The Attempt at a Solution



Cold drawn products could have internal cracks which the heat from welding causes thermal cracks to occur.
 

Answers and Replies

  • #2
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
12,798
1,670
The fact that the second break occurred in the tube material and not the weld means the weld was not at fault, i.e. the weld was done properly.
The underlying problem is that the aluminum tubing is not strong enough to support the loads being imposed on it.
The owner is going to have to get a stronger bike.
 

Related Threads on Material Engineering - Metal Forming & Welding

Replies
1
Views
3K
  • Last Post
Replies
3
Views
8K
  • Last Post
Replies
10
Views
5K
Replies
4
Views
234
  • Last Post
Replies
2
Views
1K
Replies
6
Views
5K
  • Last Post
Replies
6
Views
5K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
5K
Top