Assessment of the sheet steel surface roughness to justify the target values of its parameters

Abstract

Sheet steel roughness estimation is considered as determination of influence of surface roughness on quality characteristics and production process efficiency. A comprehensive quantitative assessment of the impact of the steel base surface roughness on the quality and quantity of the highest grade of Electrolytic Tinplate was performed. An increase in the Arithmetical mean deviation of the assessed profile (Ra), oriented perpendicular to the rolling direction, increases the tin consumption, worsens the corrosion resistance and stampability of the Electrolytic Tinplate. However, at the same timethe quantity of the highest grade products is increases. Quantitative assessment of the combined effect of the steel base surface roughness, the velocity of strip and the tinning current indicates that the effect of the roughnessis more significant for the stampability and corrosion resistance of the Electrolytic Tinplate. The mass of the coating is been defined largely bythe tinning current strength. The minimum deviation the actual mass of the coating from the nominal, satisfactory corrosion resistance of the Electrolytic Tinplate and a consistently quantity of the highest grade products are observed if the steel base surface roughness issatisfies the restrictions: 0.35 ≤ Ra ≤ 0.63 μm for a class III coating and 0.35 ≤ Ra ≤ 0.55 μm for a class II coatingper GOST 13345–85, nominal mass of which is corresponds to E8,4 and E5,6 coatings per GOST R 52204–2004.