Heat Accumulation Factor
The heat accumulation factor corrects cooling conditions in small components where successive weld passes sum up to temperature build-up. It adjusts theoretical calculations to actual workshop conditions.
Physical-Chemical Mechanism of Action
Welding small components leads to a continuous accumulation of thermal energy in the local surrounding conditions. This can cause unwanted heat buildup that impairs the microstructure and can lead to cracking.
Metallurgical Relevance & Welding Risks
Too high a heat accumulation factor can cause the material to not cool sufficiently. This can lead to glass-hard martensite formation and increased crack risk in the weld. Too low a factor, on the other hand, can lead to insufficient cooling and coarsening of the microstructure, which impairs the toughness of the material.
Workshop Practice & Instructions
For small components with successive weld passes, it is important to consider the heat accumulation factor. This can be achieved by using special welding parameters and careful cooling. A typical value for this factor is 1.2 to 1.5. If necessary, welding times should be reduced or the distance between passes increased.