At what temperature is welding not allowed?

Welding is generally not allowed at temperatures below freezing, which is 32 degrees Fahrenheit (0 degrees Celsius). This restriction is in place because low temperatures can adversely affect the properties of materials, especially those that are being welded. Cold metal can become brittle and less malleable, leading to poor weld quality and increasing the risk of defects such as cracks.

Additionally, at low temperatures, the heat-affected zone—the area of the metal that changes properties due to welding heat—can expand, potentially resulting in distortions or ineffective bonds. Therefore, when temperatures reach 0 degrees, welding operations are typically suspended to ensure the integrity and safety of the welds. This guideline helps prevent failures that could result from compromised joint strength due to unfavorable conditions.

Other temperature options, while cold, do not present the same critical concerns regarding weld quality and safety, which is why the choice of 0 degrees is the most appropriate cutoff for welding operations.