Continuous Annealing & Coating Line

Selection criteria

Furnace temperature uniformity, atmosphere (H2/N2, dew point), coating-weight control.

Supply chain

Continuous annealing and coating lines for electrical steel are among the most specialised steel-plant equipment, built by a handful of international and Chinese engineering groups. Annealing atmosphere and coating type define both core loss and how well the steel punches, so match the coating to your stamping and welding process.

Buyer FAQ

Fully processed or semi-processed steel?

Fully processed grades are finally annealed and coated at the mill, so magnetic properties are guaranteed as delivered. Semi-processed grades must be annealed by the user after stamping, typically around 750–850 °C in a controlled atmosphere, to reach rated loss. Most motor makers use fully processed steel unless they already run their own annealing furnaces.

Which insulation coating class should I specify?

Under ASTM A976 / IEC 60404-1-1 type classes, C3 organic coatings give the best punchability but do not survive annealing, C5 inorganic-organic coatings withstand stress-relief annealing and weld better, and C6 is a thicker coating for large machines. Specify the class, coating thickness per side and surface insulation resistance, and match the coating to your welding or bonding process.

Do I need stress-relief annealing after stamping?

Punching deforms a band roughly one sheet thickness wide at each cut edge, raising local loss; the effect is largest on narrow teeth in small motors. Stress-relief annealing, typically about 750 °C for around 2 h in a non-oxidising atmosphere, recovers much of it. It requires an anneal-resistant coating and adds cost, so it is mainly used for high-efficiency designs.

Where it is used