INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS
Come Join Us!
Are you an
Join Eng-Tips Forums!
- Talk With Other Members
- Be Notified Of Responses
To Your Posts
- Keyword Search
- One-Click Access To Your
- Automated Signatures
On Your Posts
- Best Of All, It's Free!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.
Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Metal and Metallurgy engineering FAQ
WELD CRACKS, DEFINITIONS, CAUSES, PREVENTION & REPAIR
Posted: 11 Jul 01
Definition: A depression left at the termination of the weld where the weld pool is left unfilled.
Cause: Improper weld termination techniques
Repair: If no cracks exist, simply fill in the crater. Generally welding from beyond the crater back into the crater.
Definition: A crack running in the direction of the weld axis. May be found in the weld or base metal.
Cause: Preheat or fast cooling problem. Also caused by shrinkage stresses in high constraint areas.
Prevention: Weld toward areas of less constraint. Also preheat to even out the cooling rates.
Repair: Remove and reweld
Definition: A crack running into or inside a weld, transverse to the weld axis direction.
Cause: Weld metal hardness problem
Definition: A crack, generally in the shape of an ôXö which is found in a crater. Crater cracks are hot cracks.
Cause: The center of the weld pool becomes solid before the outside of the weld pool, pulling the center apart during cooling
Prevention: Use crater fill, fill the crater at weld termination and/or preheat to even out the cooling of the puddle
Definition: A longitudinal crack located in the weld throat area.
Cause: Transverse Stresses, probably from shrinkage. Indicates inadequate filler metal selection or welding procedure. May be due to crater crack propagation.
Prevention: Correct initial cause. Increasing preheat may prevent it. be sure not to leave a crater. Use a more ductile filler material.
Repair: Remove and reweld using appropriate procedure. Be sure to correct initial problem first.
Definition: A crack in the base metal beginning at the toe of the weld
Cause: Transverse shrinkage stresses. Indicates a HAZ brittleness problem.
Prevention: Increase preheat if possible, or use a more ductile filler material.
Definition: A crack in the weld at the weld root.
Cause: Transverse shrinkage stresses. Same as a throat crack.
Prevention: Same as a throat crack
Definition: A crack in the unmelted parent metal of the HAZ.
Cause: Hydrogen embrittlement
Prevention: Use LOW HYDROGEN electrodes and/or preheat
Repair: (only found using NDT). Remove and reweld.
Definition: A crack in the weld that occurs during solidification.
Cause: Micro stresses from weld metal shrinkage pulling apart weld metal as it cools from liquid to solid temp.
Prevention: Preheat or use a low tensile filler material.
Repair: Remove and reweld, correct problem first, preheat may be necessary, increase weld size.
Definition: A crack that occurs after the metal has completely solidified
Cause: Shrinkage, Highly restrained welds, Discontinuities
Prevention: Preheat, weld toward areas of less constraint, use a more ductile weld metal
Repair: Remove and reweld, correct problem first, preheat may be necessary.
Repairs to Cracks
Determine the cause
Correct the problem
Take precautions to prevent reoccurrence
Generally required to repair using a smaller electrode
Here is a link to a powerpoint presenation. http://pntbeldyk.wirefire.com
Back to Metal and Metallurgy engineering FAQ Index
Back to Metal and Metallurgy engineering Forum
Product engineers and tooling manufacturers have much to gain from 3D printing: By generating low-cost physical prototypes early in the design process, they can check form, fit and function, gauge customer response and compare design iterations without commitment. Download Now
Keeping up with the demand for better, faster design flow performance while preserving the original layout hierarchy of a design can be very challenging during design verification. Download Now
Top performing companies donâ€™t just integrate PLM with their enterprise systems â€“ they also integrate PLM with their engineering tools and CAD systems. Download Now
Radial wheels can match production floor demands where debris or contaminates are present Download Now
Join Eng-Tips® Today!
Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.
Here's Why Members Love Eng-Tips Forums:
- Talk To Other Members
- Notification Of Responses To Questions
- Favorite Forums One Click Access
- Keyword Search Of All Posts, And More...
Register now while it's still free!
Already a member? Close this window and log in.
Join Us Close