Strictly control the heating temperature and time. The decarburization rate significantly increases with rising temperature; for example, above 800°C, every increase of 50°C may double the decarburization speed. Therefore, set an appropriate heating temperature based on the spring steel type (such as 60Si2Mn) to avoid overheating. Meanwhile, the holding time should be sufficient for austenitization but not too long, especially for thin-section leaf springs, where the holding time must be precisely calculated to prevent excessive heating from deepening the decarburization layer.
Additionally, the loading method affects the process. There should be gaps between workpieces to avoid stacking too densely, ensuring uniform circulation of furnace atmosphere to prevent localized accumulation of oxidizing components due to poor gas flow, which could cause severe decarburization in certain areas.
It is recommended to regularly inspect the decarburization depth during production (using metallographic or hardness methods), and adjust the furnace atmosphere parameters or heating process based on the results. This approach effectively keeps the decarburization layer within the required range (generally, the decarburization depth should not exceed 1% to 2% of the sheet thickness).
