The Research Of The Processes Of Deep Drawing Quality Galvanized Sheet Steel Produced By IF Steel

For facing price competition in national galvanized strip construction material market, entering home application material market, and improving Ansteel's galvanized strip product quality to meet the cold applying and coating requirement of galvanized strip used on home application products, it is necessary to develop high surface quality and deep drawing quality galvanized steel, and develop the process of producing deep drawing quality galvanized steel which can fit in Ansteel galvanizing line.Ansteel galvanizing lines are modified Sendzimir lines. Its in-line annealing furnace has the characteristic of rapid heating and rapid cooling. For fit the furnace characteristic and produce high quality products, a 2-factors and 4-levers experiment plan was designed and the thermo simulate experiment had been done by GLEEBLE-3800, the mechanical properties were got by tensile test, the microstructure was observed by optical micrometer, the 2nd phase and its composition was measured by TEM and EDS, the texture was measured by ODF, based on the results, the optimized annealing process had been got.In the industrial experiment, the furnace atmosphere, the zinc pot chemistry and skin pass and tension leveller process were modified, the deep drawing quality galvanized steels which had better mechanical properties and better surface qualities were produced. The main conclusions are followed:1. The yield strength and tension strength are reduced when annealing temperature increases, but when the annealing temperature is above 860 degree, the yield strength and tension strength reach the minimum value.2. The {111} texture varies at sheet thickness direction, it is low around the surface and high in the middle, and there is some a texture around the surface. The shape, size and distribution of the 2nd phase are affected by annealing temperature, the 2nd phase is small and widely distributed when annealing temperature is low, and is large when annealing temperature is high.3. The line speed mainly affects the r-value and the elongation of the steels. Line speed faster, r-value and elongation higher.4. The product mechanical properties when the strips are annealed at 860 degree can meet the requirement of technical contact, such as A80≥38%,n-value≥0.20,r-value>2.0.5. The coat quality control method expressed in this thesis can insure good coat adhesion (0a cold bend, pass) and the FB surface quality.