How to Stop Steel From Bending When Welding

Metal can bend during welding because of heat distortion. This occurs when the metal cools too quickly. Heat distortion can be frustrating, costing time and materials, which drive costs up and profits down. It takes two workers to prevent welded metal from bending: one heats the steel and then moves aside while the second person welds. The first person then heats the steel again.

Things You'll Need

• Bench vise
• Welding clamps
• Propane, MAPP or oxyacetylene torch
• Heat colors chart at Blksmth.com
• Welding helmet, gloves and full leathers
• Fully equipped welding shop

Instructions

1. Clamp the steel as rigidly as possible on each side of the area to be welded.

2. Use a propane, MAPP or oxyacetylene torch to preheat the area near the intended weld to black, which is a maximum of 1,000 degrees Fahrenheit, as shown in the heat colors chart at Blksmth.com (see References).

3. Don a welding helmet, gloves and full leathers. Make your chosen weld using appropriate equipment. Welding inspector Ed Craig at WeldReality.com has a photo gallery on how to prevent or repair bad welds (see Resources).

4. Immediately reheat the area around the weld to black.

5. Back the flame of the torch away from the weld a half-inch at a time over several minutes. Allow the part to cool to room temperature over 30 or more minutes.

Tips & Warnings

• According to chartered engineer John Dyson, if small, general-purpose electrodes are used, "(this causes) low weld heat input, which when combined with no preheat gives very rapid heat dissipation." Rapid heat dissipation leads to bending, which can cause visible and unseen cracks. These cracks can lead to failure of the part in question at a critical phase.

References

• Blksmth: Heat Colors for Blacksmiths
• GoWelding: How to Prevent Weld Failure; Section 3: Bad Welding Method

Resources

• Weld Reality: Bad Welds or Bad Management?
• American Welding Society: Welding Safety Fact Sheets