How to Detect a Cold Weld

A cold weld is often the cause of defects within metalwork. It is very hard to detect because it resembles a merger of two metal pieces. But the cold weld is created when the two metal pieces are touching piece to piece without a bonding agent between them. The weld is made around these adjoining metal pieces but never between them. This leaves a weakness in that newly created joint that can easily become a break. There are only a few ways to spot these welds before the weakness causes an issue.

1. Ask about the welding process to determine the type of weld. Before you begin investigating, determine the type of weld performed by asking the welder. Ask specifically about a cold weld.

2. Look at the weld line. Colds welds are frequent in spot welding, so test these areas first for any weakness. Test welds performed by butt welding or tee-joint welds for weakness as well. They are also common cold weld techniques.

3. Perform a bend test. Cold weld joints can bend at the weld and withstand much more pressure than unwelded materials. Bend and/or twist that metal at the weld to see if the metal breaks faster than an unwelded piece does to determine if the piece is a cold weld, according to PHLburg Technologies' factsheet on cold welding.

4. Use technology. Get a thermal scanning inspection tool like a Thermal Profiling System made by Invisible E. The system will allow you to scan the metal pieces, according to Welding Design and Fabrication Magazine. Review the output data from the system and determine if you have a cold weld. The manufacturer of the system can help you with interpreting the data retrieved.

A cold weld will break faster than a regular weld. Tests can cause damage to the object. The bending test especially can cause damage. Use a scrap piece of the metal used in the project to perform a test if necessary.

"Metal Forming Glossary," MA Metal.
"Real-Time Monitoring/Inspection for Detecting Weld Defects," Welding Design and Fabrication Magazine.