Comparison of several repair forms for rolling mill archway wear

Thread Content

1. Mechanical removal method is to remove the damaged layer on the surface of the arch through online machining to process the mating surface, and increase the thickness of the bottom plate to achieve the required elevation size. After being repaired using this method, wear will appear after a period of use, and it will need to be machined again. Repeated machining will have an adverse effect on the strength and stiffness of the arch, and this method cannot fundamentally repair the wear. 2. Repair welding requires on-site machining after repair welding to process the joint surface. Large area surfacing can easily cause the arch to deform and bend due to thermal stress. And after repair, the joint surface and lining plate will wear again due to impact and corrosion. It cannot fundamentally solve the wear and tear, and the construction period is long. It consumes a lot of manpower, material and financial resources of the enterprise. 3. Compared with traditional cladding, spraying and electroplating, laser cladding has the characteristics of small dilution, dense structure, good combination of coating and substrate, suitable for cladding materials, large changes in particle size and content, etc. Therefore, the application prospects of laser cladding technology are very broad, but often due to high cost, long construction period and other reasons, the repair cannot be completed in a short time. 4. On-site repair of polymer composite materials. Polymer composite material repair technology can be used for on-site repair. Among them, the Fushi Blue polymer composite series with better application effects. The chemical bond connection force formed by the Fushi Blue 2211F polymer composite material used for repair after curing enables it to form excellent adhesion with the repaired metal parts, which can meet the requirements of the equipment to withstand various composite forces during operation. In addition, after repair using polymer composite materials, the mating surface can reach more than 90%, achieving a gap-free fit and avoiding the corrosion problem of the arch caused by the intrusion of cooling water. On-site repair case a) Construction technology of wear problem of matching surface of rolling mill archway and lining plate: 1. First, measure according to the drawings and usage requirements, and then determine the wear amount again. ； 2. Select the corresponding repair process according to the wear amount of the mounting surface of each liner. ； 3. Use oxygen acetylene for baking oil treatment ； 4. Use a polisher to polish the surface to remove the fatigue layer and high spots. 5. Use a sandblasting machine to roughen the surface and increase the bonding area. ； 6. Use absolute ethanol to clean the surface ； 7. Apply release agent to the liner and let dry for later use. ； 8. Adjust the coating material so that the material thickness is slightly higher than the actual wear amount. ； 9. Assemble the lining plate, tighten the bolts, and the repair is completed. b) Wear construction technology of the mating surface of rolling mill archway and oil cylinder 1. Process the template with a thickness of about 30-40mm according to the length and width of the balance cylinder and reserve fastening and positioning screw holes ； 2. The surface of the rack is first treated with oil, then the oxide layer is polished, and then the surface is sandblasted. ； 3. Clean the surface of the template, apply release agent to the reserved fastening and positioning screw holes of the template, and install the top screw in place. 4. Install the template. During the installation process, use a micrometer to measure with the symmetrical lining plate as the reference plane. During the measurement process, take at least six measurements to ensure the flatness and verticality after installation and meet the installation tolerance. After the size is adjusted, remove the template and keep the jackscrews still ； 5. Calculate the amount of materials and adjust the application materials ； 6. Install the fastening template and measure the installation dimensions to ensure that the installation error is within the design tolerance. ； 7. After the material is cured, remove the template, polish the surface with sandpaper, remove the smooth layer on the surface of the material, and clean up excess material. ； 8. Apply release agent to the mating surface of the balance cylinder and rolling mill arch. ； 9. Mix the material again and apply a thin layer to the surface of the archway that needs to be repaired to achieve a 100% surface fit. ； 10. Assemble the balancing cylinder, assemble it in place, and wait for the material to solidify. ； 11. After the material solidifies, tighten the bolts appropriately again, verify the dimensions, and complete the repair. 5. Summary of the on-site repair process of polymer composite materials. The repair process was completed in 2006 for the impact wear of the rolling mill arch. During this period, online repairs have been successfully implemented for the 450-F6 four-high rolling mill, 850 roughing mill, 650 roughing mill, 550 roughing mill, and 650 finishing mill. In 2016, the online repair of the impact wear on the mating surfaces of the eight bending fixing blocks and the rolling mill arch of the 1700mm hot continuous rolling F1-F6 finishing mill was successfully completed. In 2017, the online repair of the matching surface wear problem of the 1500 hot tandem roughing mill archway and balance cylinder, the 1700 hot tandem rolling line mill archway and frame roller matching surface repair, the 1810 rolling mill archway and bottom plate matching surface repair, 1580 rough rolling lower support roll lining plate and plate The matching surface of the steel mill universal rolling mill and the matching surface of the AGC cylinder were repaired. In 2018, on-site repairs were carried out on the matching surface of the CSP continuous casting and rolling mill arch and the upper and lower support rollers and work roll linings, and the matching surface of the CSP continuous casting and rolling mill arch and CVC cylinder. Compared with traditional maintenance, it not only saves maintenance time, but also the equipment operates without abnormality after repair, and meets the requirements of traditional repair processes. It is an important technical means for on-site equipment repair and maintenance worth promoting.