In the continuous production line of steel strip, the strip is wound around tension rollers, creating friction at the contact points, which generates a tension differential between the inlet and outlet. This changes the tension value of the steel strip at the inlet or outlet of the tension roller, allowing for tension control in the system. Surface corrosion and wear are common forms of damage to tension rollers. Currently, there are various methods for surface repair and reinforcement, such as spray welding, thermal spraying, laser cladding, and electroplating, each with different repair effectiveness.

Solution: At the request of our client, we conducted surface repair and reinforcement on the damaged tension rollers. After a comprehensive analysis of the damage caused, we adopted a supersonic spraying process to coat the surface with tungsten carbide to enhance its surface hardness.

The tungsten carbide coating has gradually replaced traditional hard chrome plating due to its wear resistance. Industrial tests indicate that the roughness of the tungsten carbide-cobalt coating only decreased from 6 μm to 3 μm after 36 months, while the roughness of the chrome plating dropped from 6 μm to 2 μm after just 8 months. This demonstrates that tungsten carbide coatings have a longer service life and better surface retention capabilities.