Abstract:
Galvanizing process is one of methods for rust protection of structural steel. The HotDip Galvanized process is a popular process because it is really simple process, low cost process and life time expansion for structural steel. However, one of problem found in HotDip Galvanized is the deformation for thin steel plates of thickness less than 6 mm. As in Hot-Dip Galvanized factory in our case study, the deformation problem is found in hot-dip galvanizing processes of steel plate SS400 at size of 600 mm x 1200 mm with thickness of 4, 5 and 6 mm. Generally, this problem is corrected by using reinforcing steels, however, there is no standard for this technique. So the method of Linear Discriminant Analysis is introduced and applied to cope with this problem in this study. With the Linear Discriminant Analysis method, three main independent variable (X1: The welding position of reinforcing steels at size 320 mm to 450 mm, X2: Thickness of SS400 steel plate at size 4, 5 and 6 mm and X3: Thickness of reinforcing steels at size 6, 8 and 10 mm) and one dependent variable (Y: Deformation of steel plate) are analyzed. Finally, the calculation result shows that predictive equation of = 0.044X₁ + 0.3616X₂ + 0.1328X₃ and Q = 19.59 by it is appropriate for this problem with 92.11 % predict efficiency. After applying this equation with hot-dip galvanizing processes of case study factory, the net income is increased 60.9 % (3,147,356.94 Bahts per month) since defection rate is reduced.