What is the minimum preheat temperature when using E7018 electrode on ASTM A572 grade 42, 2” thick material?

The minimum preheat temperature when using E7018 electrodes on ASTM A572 grade 42, particularly for materials that are 2 inches thick, is indeed 150°F. Preheating is essential to reduce the risk of hydrogen-induced cracking in thicker materials and to ensure proper weld metal fusion with the base metal.

In AWS D1.1, the specified minimum preheat temperature is guided by the thickness of the material and the type of filler metal used. E7018 is a low-hydrogen electrode, which requires specific preheat temperatures to effectively mitigate the risks associated with high carbon content in the steel, such as hydrogen embrittlement.

For ASTM A572 grade 42, which has a yield strength of 42 ksi and is categorized as a carbon steel, the preheat requirement increases with the thickness of the base material. Though the code does provide flexibility under certain conditions, for a 2 inch thick section, the minimum preheat of 150°F is established to ensure adequate weld quality and structural integrity.

Higher preheat temperatures, such as 200°F or 250°F, may be required in certain scenarios, particularly if additional factors like ambient temperature or the presence of restraint are considered; however, 150°F