What is the minimum temperature of the base metal below which no welding should be performed?

The minimum temperature for performing welds on steel, as outlined in the AWS D1.1 Structural Welding Code, is critical to ensure the quality and integrity of the welds. The correct answer of 32°F indicates the lowest temperature at which welding should ideally be carried out.

Welding at temperatures below this threshold can significantly increase the risk of brittle fracture and adversely affect the mechanical properties of the base metal. Steel can reach a state where it becomes more susceptible to cracking if the temperature is too low. At 32°F, which is the freezing point of water, the risks associated with welding, such as reduced ductility and increased hardness in the heat-affected zone, begin to escalate.

This standard helps maintain the performance and reliability of welded structures, ensuring they meet the necessary safety requirements. Welding at or above this minimum temperature provides a more favorable environment for the weld metal to fuse effectively with the base metal, reducing the likelihood of defects.

In contrast, the other temperatures presented, such as 0°F, 20°F, and 50°F, either pose greater risks of undesirable outcomes or do not represent the established guideline in the code. The code emphasizes 32°F as a crucial benchmark, balancing safety and structural integrity during welding