What is the typical preheat temperature range for welding carbon steel?

The typical preheat temperature range for welding carbon steel falls between 150°F to 250°F. Preheating carbon steel is essential to reduce the risk of weld defects such as cracking, particularly in thicker sections or when welding high-strength steels. The temperature range helps to mitigate the thermal gradient and helps in the even distribution of heat throughout the material.

When steel is welded without preheating, the rapid cooling of the weld can lead to increased hardness and brittleness in the heat-affected zone. By preheating the material, it allows for a slower cooling rate and helps to maintain the ductility and toughness of the weld. This practice is especially crucial in colder environments where the risk of weld cracking is heightened due to lower ambient temperatures.

The other ranges either do not provide sufficient heat for the process or are too high for carbon steel, which would lead to unnecessary softening or even damage to the material. Hence, the chosen range is appropriate and widely accepted in welding practices for carbon steel.