Phase 1: Pre-Grinding Preparation
This Is The First Crucial Step To Ensuring Grinding Quality And Safety.
01 Roll Handover And Inspection:
(1) Rolls Removed From The Rolling Mill Are Transported To The Grinding Shop.
(2) The Operator Verifies Roll Information (Such As Roll Number, Material, And Mill Frame) And Records Surface Condition (Wear, Cracks, Steel Adhesion, Etc.).
02 Cleaning:
Use Specialized Cleaning Equipment (Such As A Pickling Tank Or Spray System) Or Tools To Thoroughly Remove Oil, Dust, And Metal Debris From The Roll Surface. Any Residue Will Damage The Grinding Wheel And Roll Surface During Grinding.
03 Flaw Detection:
Use Ultrasonic Or Eddy Current Testing On The Roll To Inspect The Surface And Subsurface For Microscopic Cracks That Are Invisible To The Naked Eye. If The Crack Depth Exceeds The Stock Removal Required For This Grinding Operation, The Roll May Need To Be Scrapped Or Undergo Further Processing.
04 Loading The Grinding Machine And Adjustment:
(1) The Cleaned Roll Is Hoisted Onto The Grinding Machine Using An Overhead Crane, And Its Concentricity And Levelness Are Accurately Adjusted Using A Dial Indicator. Any Slight Deviation Will Result In Tapered Or Crowned Rolls After Grinding.
(2) Start The Grinder And Rotate The Roll At A Low Speed.
Stage 2: Grinding Process
This Is The Core Processing Stage And Is Generally Divided Into Rough Grinding And Fine Grinding.
01 Selecting And Installing The Grinding Wheel:
(1) Select The Appropriate Grinding Wheel (Abrasive Type, Grit Size, And Hardness) Based On The Roll Material (Cast Iron, Forged Steel, Tungsten Carbide) And Hardness.
(2)Mount The Grinding Wheel Onto The Grinder Spindle And Perform Dynamic Balancing To Prevent Vibration During High-Speed Rotation, Which Can Affect Surface Quality.
02 Rough Grinding (Removing Defective Layers):
(1)Purpose: To Quickly And Efficiently Remove Fatigue Layers, Oxide Films, And Microcracks From The Roll Surface.
(2)Parameters: Use A Large Grinding Depth And A Low Roll Speed To Improve Efficiency.
(3)Coolant Is Continuously Applied During The Grinding Process To Reduce The Temperature Of The Roll And Grinding Wheel, Prevent Thermal Stress Cracks, And Flush Away Grinding Debris.
03 Fine Grinding (Achieving Dimensional And Form Accuracy):
(1)Purpose: To Achieve The Precise Diameter, Roughness, And Roll Profile Required By The Drawing.
(2)Parameters: Utilize Minimal Grinding Depth, High Grinding Wheel Speed, And Low Feed Rate To Achieve An Exceptionally Smooth Surface Finish.
(3)Roll Profile Control: This Is The Core Technology. Modern CNC Roll Grinders Use Program-Controlled Grinding Wheel Carriage Motion Relative To The Roll Axis To Grind Precise Crowns (Medium-High), Concavities, Or More Complex Curves, Such As CVC And SmartCrown Roll Profiles. The Operator Must Continuously Check The Profile Using A Template Or In-Process Measuring Instrument.
04 Smoothing Grinding:
When The Required Dimensions Are Nearly Achieved, Stop The Feed And Allow The Grinding Wheel To Dry-Grind Several Times Without Engaging The Tool To Eliminate Elastic Deformation And Further Improve Dimensional Stability And Surface Quality.
Stage 3: Post-Grinding Processing
01 Measurement And Inspection:
(1)Dimensions And Shape: Measure The Final Diameter Using An Outside Micrometer, Ring Gauge, Or Other Device. Check The Roll Profile Using A Template Or Profilometer.
(2)Surface Quality: Use A Surface Roughness Tester To Check The Ra Value (Arithmetic Mean Deviation Of The Profile) For Acceptable Quality. If Necessary, Perform Eddy Current Testing Again To Ensure That All Microcracks Have Been Completely Removed.
(3)Surface Texture: Macroetching (E.G., Using 5% Nital) May Be Necessary To Check The Grinding Pattern For Uniformity And The Presence Of Defects Such As Burn Marks And Chatter Marks.
02 Cleaning And Protection:
(1) Rinse And Air-Dry The Ground Rolls Thoroughly.
(2) Immediately Apply A Layer Of Rust-Proof Oil To Prevent Rust During Storage And Pending Use.
03 Lifting And Recording:
(1)Lift Qualified Rolls Off The Grinder And Store Them In A Designated Area For Future Use.
(1)Completely Record All Grinding Data, Including Grinding Weight, Final Dimensions, Roll Profile, Operator, Date, Etc., To Ensure Full Lifecycle Management.
Key Points:
(1)Precision: Target Micron-Level Accuracy Throughout The Entire Process.
(2)Cleanliness: Cleanliness Of Both The Rolls Themselves And The Coolant Is Extremely Important.
(3)Cooling: Adequate Cooling Is Key To Preventing Thermal Stress Cracks In The Rolls.
(4)Inspection: From Pre-Grinding Flaw Detection To Final Inspection After Grinding, We Ensure Every Detail Is Flawless.
This Rigorous Process Ensures That The Rolls Return To The Rolling Line In Optimal Condition, Producing High-Quality Steel With Uniform Thickness And A Smooth Surface.
