Best Bright Annealing Process Parameters for Stainless Steel & Copper

Even with a high-quality bright annealing furnace, unreasonable process parameters will still cause problems such as dim workpiece surface, excessive hardness and residual stress. Different metal materials have exclusive heating temperature, holding time and cooling rules. We sort out the most practical bright annealing process parameters for mainstream metal materials to help users improve finished product quality.

1. Stainless Steel Bright Annealing Parameters

For 304 and 316 stainless steel pipes and sheets: heating temperature 1050℃–1150℃, holding time 30–90 minutes (determined by workpiece thickness), adopt 75% nitrogen + 25% hydrogen mixed protective gas; slow cooling stage strictly controls cooling speed below 8℃ per minute to avoid workpiece deformation. This parameter can effectively eliminate quenching stress and present mirror bright surface.

2. Copper & Brass Annealing Parameters

Copper wires and copper connectors: low-temperature annealing at 280℃–450℃, holding time 15–40 minutes, pure nitrogen protection; brass parts need to appropriately reduce the temperature to 250℃–380℃ to prevent zinc element volatilization and surface discoloration. The process can improve the ductility and bending performance of copper workpieces.

3. Carbon Steel & Spring Steel Parameters

Low-carbon steel fasteners: annealing temperature 650℃–750℃, nitrogen-hydrogen mixed atmosphere; spring steel parts need staged heating, with holding time extended to 60–120 minutes to stabilize metal structure and enhance fatigue resistance.

4. Key Process Operation Tips

Before formal heating, pre-purge the furnace chamber for 10–20 minutes to completely discharge oxygen; avoid frequent opening of the furnace door during operation; thick workpieces should adopt staged heating to reduce temperature difference stress; do not accelerate cooling rapidly to prevent workpiece cracking.

Conclusion

Matching exclusive annealing parameters according to materials is the key to high-quality bright processing. Our technical team can provide free customized process formulas based on your workpiece specifications.