Tri-Ply Circles
Annealing Tri-Ply Circles: Why Heat Treatment Decides Drawability
Roll bonding work-hardens the metal. Annealing softens it back - get this step wrong and circles crack in the press.
What annealing does
Controlled heating + slow cooling relieves internal stresses and restores ductility (elongation). Without it, bonded coil is too hard and brittle to deep-draw.
Bright annealing
Annealing in a protective atmosphere (hydrogen/nitrogen) prevents oxidation - the surface stays bright (that’s the BA finish) and no pickling is needed. Premium process, premium result.
When it goes wrong
- Under-annealed: too hard - cracking in deep draws
- Over-annealed: grain growth - orange peel defect
- Uneven: property variation across the coil
Ask suppliers about their annealing process and temperature control - it separates mills from pretenders.
Frequently asked questions
What is bright annealing?
Annealing in a protective gas atmosphere that prevents oxidation, leaving a bright, clean surface.
Why do circles crack during pressing?
Often under-annealed (too hard) material or excessive draw ratio. Check MTC elongation values.
Have a cookware project in mind?
We manufacture triply cookware and supply tri-ply circles for OEM, private label and distribution. Tell us your specs - we reply with a quote.