METHOD AND DEVICE FOR MANUFACTURING STEEL SHEET WITH BLACK COATING Russian patent published in 2021 - IPC C23C28/00 C23C2/06 C23C8/18 

FIELD: metallurgy.

SUBSTANCE: group of inventions relates to methods for blackening a steel sheet coated by a hot method with a Zn-Al-Mg alloy in a sealed chamber, and to devices for blackening the mentioned steel sheet. The internal pressure is maintained in the sealed chamber made with the possibility of regulating the amount of water vapor supplied to the sealed chamber and the amount of gas atmosphere released from the sealed chamber. At the same time, water vapor supply to the sealed chamber and gas atmosphere release from the sealed chamber are maintained to remove hydrogen gas formed in the sealed chamber from it, thereby providing the possibility of contact between the mentioned steel sheet and water vapor. In another embodiment of the invention, the internal pressure is maintained in the sealed chamber above or equal to 80% and below or equal to 120% of the set value. The device for blackening the mentioned steel sheet contains a sealed chamber made with the possibility of placing the specified steel sheet in it, and a pressure control unit made with the possibility of regulating the amount of water vapor introduced into the sealed chamber and the amount of gas atmosphere released from the sealed chamber, while maintaining the set value of internal pressure in the sealed chamber. The pressure control unit is made with the possibility to maintain internal pressure in the sealed chamber during processing by bringing water vapor into contact with the mentioned steel sheet and at the same time ensure the supply of water vapor to the sealed chamber and the release of gas atmosphere from the sealed chamber to remove hydrogen gas formed in the sealed chamber from it.

EFFECT: uniform blackening of the coating layer is provided to obtain a steel sheet with black coating of improved appearance.

4 cl, 3 dwg