products

Main Data

  • Description: Rolling mill screw-down screw shaft
  • Screw thread type: buttress thread form
  • Screw thread pitch: 45 mm
  • Starts of threads: 2
  • Helical hand: Right
  • Accuracy of screw thread: 
    • Single pitch error shall be less than ±1%
    • Accumulated error shall be less than ±5%
  • Screw shaft: 
    • Material of screw shaft: Alloy steel
    • Heat treatment: Quenching and carburizing
    • Hardness: HS30~35
    • Thread surface finish: Turning
    • Major diameter: 390 mm
    • Pitch diameter: 361 mm
    • Minor diameter: 331 mm
    • Height of thread: 29.5 mm
    • Spline part:
    • Tip diameter: 440 mm
    • Normal circular thickness: 70 mm
    • Whole tooth depth: 60 mm
    • Number of teeth: 8
    • Length: 1100 mm
    • Spline surface finish: Ground
  • Nut
    • Material: Copper alloy
    • Hardness: 100HBS
    • Thread surface finish: Milling
    • Number of threads: 11
    • Out Diameter: 650 mm
    • Major diameter: 394 mm
    • Pitch diameter: 361 mm
    • Minor diameter: 332 mm
    • Height of thread: 31 mm
    • Length: 590 mm

The Main Fabrication Procedure

  • Screw shaft 
    • Forging the shaft blank
    • Normalizing
    • Rough turning
    • Ultrasonic inspection
    • Quenching and tempering
    • Semi-finish turning
    • Grinding the splines
    • Turning threads
    • Inspection magnetic inspection the thread flank, and then magnet demagnetization
    • Facing up
  • Nut 
    • Centrifugal casting
    • Rough turning
    • Semi-finish turning
    • Milling the threads
    • Facing up

Technical Documents

  • Inspection certificate of material
  • Mechanical property test report 
  • Heat treatment certificate
  • Non-destructive inspection(Certificate of ultrasonic inspection)
  • Record of hardness
  • Magnetic particle detection certificate(on tooth flank)
  • Size tolerance and geometric tolerance report
  • Inspection report of thread quality

Application

  • Rolling mill screw-down mechanism