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