Quenching Medium
Quenching medium is a fluid or gas used for targeted heat removal during quenching. Its heat transfer coefficient determines the achievable hardness.
Physical-Chemical Mechanism
The quenching medium transfers heat from the weld to the surrounding area. The higher the medium's heat transfer coefficient, the faster it cools.
Metallurgical Relevance & Risks in Welding
A poor quenching medium can cause uneven cooling and result in an incorrect microstructure. This can lead to hardness variations, cracks, or grain coarsening in the material.
Workshop Practice & Instructions
For high-strength steels with high carbon content (e.g., martensitic), use a medium with a high heat transfer coefficient like water or glycol. For softer steels, oil or a polymer solution is better. Always ensure the correct temperature of the quenching medium and its cleanliness.