Induction Hardening Frequency Selection
The induction hardening frequency selection determines how deep the electromagnetic heat penetrates into the workpiece. A high frequency (e.g., 10 kHz) results in a thin, fast penetration depth, while a low frequency (e.g., 50 Hz) allows for a deep, slow penetration depth.
Physical-Chemical Working Mechanism
Induction hardening uses electromagnetic fields to heat the workpiece. The frequency of the alternating current determines the depth of heat penetration. High frequencies (e.g., 10 kHz) produce short wavelengths and lead to fast, surface-level penetration. Low frequencies (e.g., 50 Hz) have longer wavelengths and allow for deep, slow heat transfer.
Metallurgical Relevance & Welding Risks
Choosing the right frequency is crucial for hardness distribution in the workpiece. Too high a frequency can cause overly rapid cooling, resulting in a glass-hard, crack-prone structure (martensite). Too low a frequency coarsens the grain and reduces toughness, leading to fracture risk and poor mechanical properties.
Workshop Practice & Action Items
For a thin, fast penetration depth (e.g., on thin sheets), choose a high frequency of 10 kHz or higher. For a deep, slow penetration depth (e.g., on large parts), use a low frequency of 50 Hz or less. Ensure that cooling after induction hardening is controlled to achieve a uniform structure.