Annealing heat treatment method and pickling method of high manganese steel cold rolled steel sheet

摘要

The present invention relates to an annealing heat treatment method for minimizing the surface oxidation of a Fe-Mn-Al-C high manganese steel cold rolled steel sheet used for steel sheets for automobile steel sheets and electromagnetic panels requiring high moldability and high strength, The present invention relates to a pickling method, in which the thickness of the oxide layer on the surface of the steel sheet is controlled to 1 m or less by appropriately controlling the atmospheric gas blanket of the annealing heat treatment furnace and the mixing ratio thereof to distribute pore AIN precipitates in the oxide layer so that the oxide layer can be easily removed in the next step And a method for removing the surface oxide layer of the high manganese steel cold-rolled steel sheet. The present invention relates to a method of annealing a conventional Fe-Mn-Al-C high manganese steel cold rolled steel sheet at a temperature of 500-1000C in a gas atmosphere in which the atmosphere gas is mixed with 100% nitrogen or 50% Characterized in pickling the surface of the surface oxide layer with an aqueous hydrochloric acid solution at a concentration of 0.06-0.8% by weight, an aqueous hydrochloric acid solution at a temperature of 15-50C, and a pickling time of 30-90 seconds in order to remove the surface oxidation layer. A method of manufacturing a manganese steel cold-rolled steel sheet.