Roll is an important consumable in steel rolling process and one of the main products of large-scale casting and forging enterprises. Roll recycling is no doubt the roll from consumables into recyclable durable goods, only the work layer of the roll as a consumable. However, if you want to achieve the cycle of roll use must meet the following basic

conditions:
      1, a repair of the roll service life is greater than equal to the original roll service life. If the performance of the repaired working layer is consistent with that of the original roll, the thickness of the unilateral increased working layer should be 80mm ~ 100mm. If the quality of the repaired working layer is much higher than that of the original roll, the thickness of the working layer can be reduced appropriately.
      2. During the repair process of the roll, the roll substrate remains basically unchanged, can be used repeatedly, and the stress state of the roll substrate is good after repair.
      3. The newly added working layer has a good combination with the roll substrate, can bear the complex stress state, without the defects of relative sliding, spalling and cracking of the working layer.
      4. The new working layer has high anti-spalling performance, good anti-wear performance and anti-fatigue performance, no defects in the working layer, uniform hardness and microstructure. The main methods of roller circulation use:
      1, surfacing technology, surfacing technology is a kind of welding method which uses electric welding or gas welding to overlay the molten metal on the tools or machine parts. As a traditional repair technology, surfacing technology has been used in the field of roll and large-scale casting and forging, which is a common and mature technology in roll recycling industry.
      2, insert the sleeve technology, the work layer and the roll substrate by two or more materials of the composite roll produced. It is one of the important methods to use interference fit to combine the high strength working layer jacket with the high toughness roll body. The roll base, which accounts for more than 80% of the total roll, can not be

changed in the rolling process and can be recycled. The Roll Shell, which accounts for less than 20% of the total roll weight, is continuously consumed in the rolling process, replacement of roll sleeve after reaching scrap standard.
      3. Cladding technology, laser cladding is a new surface strengthening technology of roller in recent years. It is to use high energy laser beam to heat the surface of roller, at the same time, by melting the cladding layer material on the substrate surface and rapidly solidifying by the self-cooling of the substrate, a compact cladding layer bonded to the substrate is obtained. The roll recycling technology not only can increase the benefit of the enterprise through the maintenance service, but also can develop the compound roll. It is also an important core technology for the long-term development of roll manufacturing enterprises. Hot Strip, work roll, cold mill