What temperature should the rail head and base be preheated to if the rail temperature is between 0 and 40 degrees?

In thermite welding, preheating the rail head and base plays a crucial role in ensuring the quality and integrity of the weld. When the ambient temperature is between 0 and 40 degrees Fahrenheit, it is important to raise the temperature of the rail to a level that minimizes thermal shock and promotes effective bonding during the welding process.

Preheating the rail head and base to 110°F is an appropriate choice within this temperature range. This temperature helps to reduce the risk of cracking and other defects that can occur due to the rapid cooling of the molten metal in colder temperatures. A preheat of 110°F ensures that the material is adequately warmed to allow for the best possible weld characteristics without overheating the steel, which could lead to other complications.

Selecting a lower temperature, such as 100°F, might not sufficiently address the thermal stresses involved in the welding process, while temperatures like 120°F or 130°F could exceed the necessary preheating range for this scenario, potentially leading to issues such as warping or weakening the steel. Therefore, setting the preheat at 110°F is a balanced approach to effective thermite welding in the given temperature conditions.