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Why is the purchased backup roll not durable?


Due to the use environment of the backup roll, it must bear a large radial force, so it is the most critical mechanical part of the equipment except the work roll. Many equipment manufacturers do not understand the structure of the backup roller, and use ball bearings and bushing parts to assemble the backup roller by themselves. This kind of backup roller is extremely insufferable, and the poor accuracy affects the use.

The real backup roll should be composed of mandrel, bearing sleeve, needle roller, seals, fasteners, heat-resistant extreme pressure grease, and the heat treatment hardness, material selection, clearance fit, assembly and debugging of each part have specifications and requirements . In the tension leveling line below 450 m/min, the service life of the backup roller should be between half a year and two years (depending on the initial plate type and use environment). If the backup roller is broken in two or three months, please Inform the supplier in time, it is basically a quality problem or improper use.


There are generally three reasons why the backup roll is not durable:


  1. The quality of the backup roller itself. Open the backup roller, if it is found that the internal structure is assembled with standard parts such as bearings, it is basically an inferior product. The inside of the real backup roller should be composed of needle rollers or needle rollers with cages, and the backup roller itself is a non-standard bearing. Install the backup roller on the roller box and measure its circular runout. If the circular runout is larger than 0.01mm, it is also bad, please replace it in time.
  2. Wrong selection. When the plate exceeds 0.3MM or the production speed of the tension leveling line exceeds 300 m/min, it is not recommended to use a light-duty backup roll with a cage, and a heavy-duty backup roll with a full complement of rollers is used. After dismantling the backup roller, if the inner roller (cylindrical needle roller) is covered by a ring cage made of nylon, brass, cast iron, etc., then the backup roller is a light-load type, and it is recommended to find a supplier for replacement.
  3. The roll box accuracy is not good. The accuracy of the roll box directly affects whether the backup roll can contact the work roll or the intermediate roll. If some backup rolls rotate and some do not rotate when the machine is working, it means that the non-rotating backup rolls do not bear the load, and the backup rolls of the roll box are installed. The face is high and low. In this way, the bearing of each backup roller will be uneven, and the force will be broken quickly, and the force will not work. It is recommended to re-process the mounting surface of the roller box, and it is better to grind the guide rail and pull a knife as a whole. After installation, measure the paste liquid with red powder, blue oil, etc. to check the force of the backup roller. If there is still a precision error, it can be adjusted with a 5-micron level adjustment sheet.

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As professional one-stop solution provider, LIAONING MINERAL & METALLURGY GROUP CO., LTD(LMM GROUP) Established in 2007, and focus on engineering research & design, production & delivery, technology transfer, installation & commissioning, construction & building, operation & management for iron, steel & metallurgical industries globally. 

Our product  have been supplied to world’s top steel manufacturer Arcelormittal, TATA Steel, EZZ steel etc. We do OEM for Concast and Danieli for a long time.

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Core technology products:

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  • slide gate plate
  • graphite electrode

Core technology products:

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  • cast steel rolls
  • tungten carbide ring roller

Core technology products:

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