Vertical Raymond Mill Body Liner

Wear debris contaminates products and is reassumed to be one cause of reduced brightness of the product. The main cause of the Problem is: Air transports (conveys ) the powdered product ground inside vertical mill. This causes severe erosion on the body liner. The resulted wear debris are conveyed along with the product. The Solution: The wear liners were selected with following MOC. a) Boiler quality base plate of 6mm overlaid with chromium carbide containing weld alloy of 4mm thickness. Weld alloy was Eutectic OA 4601 teromatic wire and was welded using REISS robot on a water-submerged plate. The deposited alloy had 56 HRC hardness.Though harder and more wear resistance carbides deposits were available; their use was restricted by the subsequent bending of wear liners to the fit the body. The inside geometry of the vertical mill body and the location of retaining holes were non-standard and varied on a mill-to-mill basis causing fitting delays. b) Packing material failure due to sleeve surface roughness. c) Mild steel plate of 10mm thickness was coated with Ni-Cr-B-Si alloy containing tungsten carbide to a concentration of around 50%. The deposit thickness was 0.4mm and hardness was around 60 HRC for the matrix and 850 Vickers for the carbide particles. Deposits were applied by the spray and fuse process and powder used was SF 15211/SF 10112 of Eutectic. Equipment by which spray had been done is Castodyn 8000 of Eutectic+Castolin Switzerland. The process is fast and plates can be bend to one desired shape without many efforts. Fitment is also relatively easy. The cost of providing the needed 0.8mm thick coating may be high.