Holding time
Hold time is the time a component is kept at the target temperature to ensure complete through-heating or phase transformation. Too short times can lead to incomplete transformation and porosity, while too long times can cause hardening and embrittlement of the material.
Physico-Chemical Mechanism of Action
The holding time refers to the time during which a component is kept at a specific temperature. This is crucial for through-heating and possible microstructural transformations in the material. If the time is too short, the material cannot be fully heated through, which can lead to incomplete transformations and porosity. If it is too long, the material can become overhardened, leading to embrittlement and possible cracking.
Metallurgical Relevance & Welding Risks
Too short holding times can lead to incomplete transformation of the microstructure, which can cause porosity and reduce mechanical properties such as strength and toughness. Too long times can overharden the material, leading to embrittlement and possible cracks in the component. This can significantly shorten the part's service life and lead to safety issues.
Workshop Practice & Action Guidelines
The holding time must be strictly observed to ensure complete through-heating and microstructural transformation. This can be ensured by using thermostats and timing devices. Specific holding times for different materials and welding processes are given in the manufacturer's technical data sheets or manuals. It is important to follow these times exactly to ensure optimal weld quality.