Induction hardening
Induction hardening is a fast surface hardening process where the surface of a material is heated and cooled by a magnetic alternating field. This increases the hardness and strength of the surface layers.
Physical-Chemical Working Mechanism
Induction hardening uses a high-frequency magnetic alternating field that induces electricity in the metal part. This creates a local heat zone on the surface of the material through self-induction. The surface is heated in a flash and then quenched immediately.
Metallurgical Relevance & Welding Risks
The rapid hardening can cause local stress buildup, which may lead to cracks or distortion in the material. It is important that the material is suitable for induction hardening and the alternating field is set up correctly to achieve uniform hardness distribution.
Workshop Practice & Action Items
• Equipment: Use an induction hardening machine with a high-frequency alternating field (e.g., 50 kHz).
• Preparation: Clean the surface of the material thoroughly and remove any dirt or paint.
• Settings: Set the hardness target according to the desired end goal (HRC 30 to 60).
• Procedure: Place the material in the alternating field and start heating. The duration of the hardening cycle depends on material thickness, usually 1 to 2 seconds.
• Post-treatment: Quench the surface immediately after the hardening cycle with cold water or air.