Custom Manufacturer Of Pinch Rolls And Tension Rolls For Hot-Dip Galvanizing Lines

Positioned immediately downstream of the uncoiler shear and adjacent to the guide table, the pinch roll assembly comprises two rolls:​

Lower Roll: A fixed, non-driven roll featuring a chrome-plated surface.​

Upper Roll: A motorized roll with a polyurethane-coated surface, mounted on a swing frame actuated by a pneumatic system to facilitate lifting and lowering. The roll is driven by an AC gear motor equipped with a brake, transmitting torque through a universal coupling. Positioning is monitored via proximity switches.​

During strip threading, the pinch roll remains open to receive the strip head. Once the strip passes through the guide table, a photoelectric sensor detects its presence, prompting the pinch roll to close. The engaged rolls then advance the strip head forward, ensuring smooth threading and preventing strip accumulation.​

At the end of the coil, the drive system synchronizes the upper roll's speed with the line speed. The pinch roll then closes to tension the strip tail, maintaining strip alignment and preventing tension loss or deviation.

Typically, a tension roll assembly consists of two tension rolls and one press roll. In specific sections, such as the exit of the annealing furnace, configurations may include three tension rolls or two press rolls to increase the wrap angle, accommodating significant tension differentials between the furnace and zinc pot areas.​

The assembly includes:​

Tension Rolls: Surface-treated to enhance friction, commonly through rubber lining or tungsten carbide coating. While rubber linings require annual replacement due to wear and potential deformation, tungsten carbide coatings offer superior durability, with a hardness of 1100–1300 HV, thickness of 0.08–0.1 mm, and surface roughness (Ra) of 3–5 µm.​

Press Roll: Typically rubber-lined using polyurethane or Hyplon, featuring a Shore A hardness of 80–85° and a rubber layer thickness of 15–25 mm.​

Tension rolls are available in two structural types:​

Through-Shaft Design: Offers higher structural integrity, albeit at a slightly increased manufacturing cost.​

Half-Shaft Design: Provides cost efficiency and ease of maintenance.​

In post-galvanizing sections, tension rolls are equipped with scraper systems to maintain surface cleanliness.