Martensitic Residual Stresses
Martensitic residual stresses arise from rapid cooling of steels, causing a severely distorted lattice. These stresses can cause cracks and hot cracks.
Physical-Chemical Action Mechanism
Martensitic residual stresses come from fast cooling of steels, where the lattice suddenly shifts to higher strength and density. This causes strong volume-increasing lattice distortion, creating internal compressive and tensile stresses.
Metallurgical Relevance & Welding Risks
These stresses can cause cracks and hot cracks, especially if cooling is too fast. They increase the risk of fracture and reduce the mechanical properties of the weld.
Shop Practice & How-To
To minimize martensitic residual stresses, control the cooling. For steels with high martensite-forming ability (e.g., high-carbon steels), slow cooling or temperature control is essential. The critical t8/5 time should be between 10 and 20 seconds to get a balanced structure.