1. The influence of the tensile strength or hardness of the steel wire
The steel wire has high tensile strength and high hardness. During the flattening process, the resistance of the steel wire to longitudinal movement per unit volume increases and the elongation decreases. However, the unit volume of the steel wire moves laterally where the resistance is smaller, and the width increases. On the contrary, the steel wire is easy to elongate in the longitudinal direction, and its width is reduced. This is the reason why the steel wire has high hardness, easy to widen, low hardness, easy to stretch but not wide. In the event of large deviations in the tensile strength of the steel wire and poor uniformity of the hardness of the steel wire rod, the width of the rolled billet will vary greatly, which will seriously affect the quality of the billet.
2. The influence of steel wire surface roughness
In the rolling process, if the surface of the steel wire is rough, the relative friction coefficient between the steel wire and the roll increases, the friction resistance increases, the elongation of the steel wire decreases, and the spread increases. In the production, the material of the weighted leather is easy to widen because of its rough surface. On the contrary, the surface of the steel wire is smoother, because the friction resistance between the steel wire and the roll is small, it is easier to elongate and the spread is smaller. In order to prevent rust, the surface of domestic steel wire is coated with butter. If the butter is not clean, it is easy to slip during flattening, which also affects its width.
3. The influence of the chemical composition of the steel wire and the metallographic structure
The higher the carbon content of the steel wire, the worse its plasticity, the smaller the compression rate and elongation of the steel wire, the smaller the deformation of the steel wire during rolling, and the smaller its width. For alloy steel wires, since the alloying elements dissolved in the solid solution can increase the hardening rate of the steel wire during cold work, its deformation resistance is large, its width is small during rolling, and it is easy to be brittle.
