Thermal affected zone
The heat-affected zone is the area of the material that is altered in its microstructure by the thermal input of the cutting process without being melted. This can lead to unwanted hardness changes.
Physical-chemical mechanism of action
The heat-affected zone is created by localized heating of the material during the cutting process. The surface and immediate surroundings are briefly brought to elevated temperatures without melting the entire material. This leads to microstructural changes in the high-temperature area.
Metallurgical relevance & risks in welding
The heat-affected zone can cause unwanted hardness changes and thus crack formation. Excessive hardness in this zone can impair the toughness of the material, which can be dangerous especially under stress or strain.
Workshop practice & instructions
To minimize the effects of the heat-affected zone, it is important to design the cutting process so that the maximum temperature in this area is limited. This can be achieved by using optimized cutting tool sharpness and suitable material. For heavily stressed components, it is advisable to allow careful cooling after cutting to control microstructural changes.