PALL Carbon Equivalent
PALL carbon equivalent is a criterion for evaluating the weldability and crack resistance of high-strength, thermomechanically rolled fine-grain structural steels. It helps in selecting the right welding process and sampling.
Physical-Chemical Mechanism of Action
The PALL carbon equivalent (PCE) measures the carbon content effects in high-strength steels. It considers both the direct carbon content and the effects of thermomechanical rolling and fine-grain structure.
Metallurgical Relevance & Risks in Welding
A too high PALL carbon equivalent can lead to the formation of glass-hard structures that are prone to cracking. This increases the risk of hot cracks and reduces the toughness of the weld.
Workshop Practice & Actions
Before starting to weld, the PALL carbon equivalent of the steel should be determined. With a high PCE (> 0.5 %), careful sampling and a suitable welding process are essential. For high-grade steels (e.g., HRC > 40), use slow cooling and controlled welding parameters to avoid cracking.