IRON PLATING SOLUTION FOR PRETREATMENT UNDERPLATING FOR MANUFACTURING GIGA STEEL WITH NICE-LOOKING SURFACE FOR HIGH-TENSION AUTOMOBILE STEEL SHEET

摘要

The present invention relates to an iron plating solution for pretreatment underplating for manufacturing giga steel with a nice-looking surface for a high-tension automobile steel sheet. According to the present invention, the iron plating solution for pretreatment underplating, which is used as an electrolyte for underplating base steel on an apparatus located between a base thermal treatment (located before a non-oxidizing annealing furnace process for annealing) and a pretreatment process for cleaning the surface of a steel sheet for the cleanliness of the base steel during a galvanized steel sheet manufacturing process, includes: salt containing iron; alkali salt for adjusting or increasing pH of an iron plating solution; an oxidation preventing agent and a complexing agent for inhibiting the generation of iron oxides and precipitates in the iron plating solution; a surface improving agent (leveling agent) for flattening an iron plating film coated on the base steel; an eutectoid agent (precipitation assisting agent); and a stress reducing agent. Therefore, according to the present invention, since an unoxidized pure iron plating layer is formed by electrically plating a cold rolled steel sheet base layer (a general cold rolled steel sheet and an automobile high-tension steel sheet) with iron after conducting a pretreatment process (de-oiling, pickling) on the base layer, metal particles (Mn, Si and the like) can be inhibited from being discharged from the base layer of the cold rolled steel sheet or high-tension steel sheet due to an external physical, thermal or chemical shock, and an un-plated defect on a plated surface can be completely inhibited after galvanizing on the base layer, so a galvanized steel sheet with a nice-looking surface can be produced.;COPYRIGHT KIPO 2020