摘要 |
A combined gas wiping die and closed protective atmosphere chamber for treating linear material issuing from a molten metal coating bath is provided with gas exit orifices leading from the hood to the external environment. The gas exit orifices have a combined cross sectional area less than the total cross sectional area of the throat of the wiping die. The combined wiping die and protective chamber with limited area exit orifices is used with a wiping gas such as nitrogen or argon. The thickness of molten coatings on linear material wiped with the combined die and protective chamber can be very accurately controlled by changes in wiping gas pressure. |