Specialty coated rollers are used in a wide variety of applications in the metallurgy industry. The coating is selected based on process parameters such as wear, tension, temperature, abrasion, etc. A wide variety of specialty coating such as various types of carbides, alloys of chrome & boron, etc. can be provided. These are deposited by varied processes such as HVOF, electroplating, arc cladding, etc.
Bridle roller, chrome roller, tungsten carbide roller, boron carbide roller, wrapper roller, tension roller, looper roller, damming roller, infeed roller.
The specialty coating rollersare mission critical&the bonding of the coating with the substrate is of paramount importance. The overlay & surface finish of the roller has to be suitable for the application under consideration. This drives performance & improvesmetal strip product quality
The process parameters such as wear, temperature, tension, abrasion, etc. are the key properties to be considered for coating & substrate selection. HVOF coating are increasingly being preferred over electroplating process (for their excellent bonding & density, low porosity & resistance stress & high wear resistance). The application of coatings by welding process has to take notice of pre-weld / post weld head treatment requirements.
The roller shells are ND tested (in proof machined condition) to determine surface / internal defects. The selected overlay is then applied on the barrel using the appropriate processes. The various tests prescribed by the appropriate standards are carried out on test coupons (using the same lot / heat as the materials). After completion of testing, the roller barrel is suitably finished. Various parameters such as TIR, hardness, chemistry, etc. are measured &recorded.
After all quality parameters are satisfactorily met, a coat of anti-rust chemicals is applied on the bearing journals / ends. The barrel of the roller is wrapped with plastic paper & then with a runner. The rollers are then packed in individual sea-worthy wooden boxes (or as mutually agreed).