Abstract
When a cold drawn mild or hard steel wire is aluminum coated by hot-dip process, the tensile strength decreases to between 50 and 60% of the original tensile strength.
Hereby, we applied hot-dip Al-coating on any cold drawn mild (0.1%C) and hard (0.6%C) steel wire by passing them through molten commercial pure Al, Al-0.2% Be and Al-0.2% Be-5% Si bath respectively, and then attempted to revive the tensile strength of these aluminized steel wires by cold drawing. At the same time, we investigated the change of other mechanical properties and corrosion resistance by cold drawing.
Both the aluminized mild and hard steel wire by passing through the molten Al-Be or Al-Be-Si bath show comparatively quicker revivification of the tensile strength by cold drawing process than the aluminized steel wire by passing through molten commercial pure aluminum bath.
When a cold drawn mild steel wire (0.1%C) is applied with hot-dip aluminum coating, it is possible to revive up to nearly the original tensile strength before coating by after cold drawing of about 70% total reduction.
When any cold drawn hard steel wires (0.6%C) are applied to hot-dip aluminum coating by passing them through molten commercial Al or Al-Be-Si bath, they can be cold drawn to 40% and 60% total reduction respectively, and then it is possible to revive up to about 70% and between 80 and 95% of the original tensile strength before coating respectively. Beyond these reduction, the torsion and wrapping tests on these after cold drawn aluminized steel wires show worse result, so these over drawn steel wires become impossible to be used as wires for any purposes.
The corrosion resistance of these cold drawn aluminized steel wires become worse proportionally to the increase of the reduction of cold drawing, accordingly to the decrease of the thickness of coated layer.
Generally, the steel wire applied to Al-coating by passing it through molten Al-Be-Si bath can be cold drawn without cracking of coated layer and shows much superior corrosion resistance than the steel wires coated by the other two simpler molten metal bathes.
