Research and Application of Low-Frequency Induction Hardening Technology for Large Backup Rolls

　　A large-scale backup roll induction quenching integrated equipment was developed with complete localization based on the one-shot method principle. The innovative application of high-power low-frequency (4MW/25Hz) digital power supply and multi-turn variable tap technology for induction coil ensures the uniformity of the temperature field on the surface of the backup roll body ≤ ±5℃. Combined with multi-furnace engineering temperature field tests, the induction heating simulation technology for large backup rolls was successfully developed, achieving full coverage of induction quenching technology applications for nearly 70 specifications of backup rolls (including φ1000mm~φ1650mm×1200mm~2400mm). A large number of industrial application practices have shown that the independently developed low-frequency static integral induction quenching integrated technology for large backup rolls can stably achieve the technical indicators of "roller body hardness uniformity △≤±1HSD" and "zero" hardness drop at 100mm in the radial direction of the working layer, with the hardness quality of the rolls reaching the international top level.
　　Key: Large backup roll; High-power low-frequency; Integral induction; Simulation modeling; Industrial application