METHOD FOR PRODUCING COATED STEEL SHEET IN DEVICE CONTAINING PREHEATING SECTION, HEATING SECTION AND HOLDING SECTION Russian patent published in 2024 - IPC C21D8/02 C21D1/34 C21D9/46 C22C38/02 C22C38/04 C23C2/06 C23C2/12 

FIELD: metallurgy.

SUBSTANCE: method for producing a coated steel sheet in a device containing a preheating section, a heating section, and a holding section includes: A) a calibration step; and B) a step in which the steel sheet is subjected to recrystallization annealing and coating by immersion in a zinc-based or aluminium-based melt bath. Moreover, at calibration stage A), a steel sheet having the composition, wt.%: 0.05 ≤ C ≤ 0.50, 0.3 ≤ Mn ≤ 8.0, 0.01 ≤ Si ≤ 5, and, optionally, at least one of the following: 0.01 ≤ Al ≤ 1.5, B ≤ 0.004, Co ≤ 0.1, 0.001 ≤ Cr ≤ 1.00, Cu ≤ 0.5, 0.001 ≤ Mo ≤ 0.5, Nb ≤ 0.1, Ni ≤ 1.0, Ti ≤ 0.1, N ≤ 0.01, P < 0.1, S ≤ 0.01, V < 0.2, the balance of the composition is iron and inevitable impurities, as long as the specified quality coating will no longer meet the specified target value, the penultimate dew point DP_CAL is determined as DP₁, and if the specified coating quality is unsatisfactory, repeat the calibration steps with a higher dew point DP_CAL until the specified coating quality meets the specified to the target value, with the final DP_CAL defined as DP₁.

EFFECT: calibration determines a lower dew point to achieve uniform coating of the steel sheet.

13 cl, 4 dwg, 3 tbl