Description: The precision rolling unit is crucial for ensuring high-precision rolling in high-speed wire mills. Therefore, tungsten carbide roll rings must be used to guarantee both rolling speed and wear resistance. To date, no alternative material has been found to replace tungsten carbide roll rings in high-speed wire mills.
Keyword: High-speed wire rolling mill, rolling mill roll material selection
Tungsten Carbide Roll Rings in High-Speed Wire Mills
High-speed wire mills are characterized by fast rolling speeds, high product accuracy, excellent surface quality, large rolling volumes, and a torsion-free and micro-tension-free rolling process. A typical high-speed wire rolling mill consists of a roughing unit, intermediate unit, pre-finishing unit, and finishing unit, with the entire line generally comprising 28 to 30 stands.
Each rolling unit typically includes 4 to 8 stands. Due to high rolling temperatures, large sections, and deep grooves, the rolls must possess good fracture resistance, thermal crack resistance, wear resistance, and biting performance. Commonly used rolls include nodular cast iron rolls with a hardness of HSD 45–55 or alloy semi-steel rolls with a hardness of HSD 45–50.
Rolls in the intermediate unit require good wear resistance and surface roughness durability, with little variation in material selection. Thus, nodular iron rolls with a hardness of HSD 60–70 or alloy indefinite chilled cast iron rolls are generally selected for their economic and practical benefits.
The pre-finishing unit in high-speed wire mills helps reduce rolling incidents and improves the dimensional accuracy of the finished wire. Roll materials for this unit should serve as a transition between previous and subsequent stages, with wear resistance being the primary consideration.
Globally, a wide range of materials is used for pre-finishing roll rings in high-speed wire mills. Some manufacturers use tungsten carbide roll rings, which offer excellent wear resistance but are prone to fracture due to low strength. Centrifugal composite roll rings and high-speed steel rolls provide three times the wear resistance of high-nickel-chromium indefinite chilled cast iron, higher strength than tungsten carbide roll rings, and a more cost-effective price. Therefore, centrifugal composite rings and high-speed steel rolls are emerging as the preferred materials for future roll applications.
The precision rolling unit is a critical component for achieving high rolling accuracy. Hence, tungsten carbide roll rings remain essential in high-speed wire mills to maintain rolling speed and wear resistance. To this day, no material has successfully replaced tungsten carbide in this application.
