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Wear detection and repair technology of crane hook

2025-07-29 06:23:02

Technical Guide for crane hook Wear Detection and Repair

(covering testing methods, repair processes, scrapping standards , in compliance with GB/T 10051, EN 1677 and other standards)

1. Wear detection method

1. Conventional testing methods

Test items Tools and Methods Allowable wear limit
Increased opening Caliper measurement (compared to original size) ≤10% original size (oversize and scrapped)
Dangerous section wear Ultrasonic thickness gauge/caliper measurement ≤5% of the section thickness (scrap if exceeding the limit)
Local wear on the hook Magnetic particle testing (MT) or penetrant testing (PT) No cracks and wear ≤3mm
Thread wear Thread gauge inspection Effective thread engagement length ≥80%

2. Intelligent detection technology

  • 3D Scanning Imaging : Laser scanning reconstructs the wear profile with an accuracy of ±0.1mm.

  • Internet of Things (IoT) Monitoring :

    • Strain gauges + wireless transmission monitor stress changes in the wear area in real time.

    • Example: After installing sensors on the hooks of a port, the accuracy of wear warning increased by 90%.

2. Restoration Technology

1. Repairable conditions

  • Wear amount : does not exceed the scrap standard (opening ≤ 10%, wear ≤ 5%).

  • No cracks : No hidden defects found in magnetic particle inspection.

2. Repair process

(1) Surfacing repair

  • Applicable scenarios : local wear (such as hook tip, stress-bearing surface).

  • step :

    1. Surface treatment : Grinding to remove the oxide layer, cleaning with acetone.

    2. Preheating : 150~200℃ (to prevent cold cracks).

    3. Surfacing materials :

      • Low alloy steel welding wire (such as ER80S-D2, matching 34CrMo4 steel).

      • Stainless steel welding rods for marine environments (such as E309L).

    4. Post-processing :

      • Slow cooling + tempering (eliminating welding stress).

      • Machined to size (lathe/grinder).

(2) Metal spray repair

  • Applicable scenarios : large area uniform wear.

  • Process :

    • Arc spraying (material: FeCrNi alloy, coating thickness ≤ 2 mm).

    • Machining + polishing is required after spraying.

(3) Sleeve reinforcement

  • Applicable scenarios : thread wear or local damage to the hook neck.

  • method :

    • The worn areas are turned and inserted with high-strength alloy steel sleeves (interference fit).

3. Post-repair verification

  1. Non-destructive testing :

    • Secondary magnetic particle inspection (to confirm that there are no welding cracks).

  2. Mechanical testing :

    • Static load test : 1.25 times the rated load, suspended for 10 minutes (GB/T 10051).

    • Hardness test : The hardness of the repaired area must be consistent with that of the parent material (±10%).

4. Unrepairable scrapping standards

The product must be scrapped if any of the following conditions occur :

  • Cracks (of any length or depth).

  • The opening increases by >10% of the original size.

  • Dangerous section wear > 5% or local wear depth > 3mm.

  • Thread failure (stripping, breakage).

5. Preventive maintenance recommendations

  1. Regular inspection :

    • Visual inspection every shift and precision measurement every month.

  2. Lubrication and anti-wear :

    • Apply wear-resistant grease (such as molybdenum disulfide) to the wire rope contact surface .

  3. Environmental protection :

    • In corrosive environments, use galvanized hooks or spray anti-rust paint regularly.

6. Technology Trends

  • Laser cladding repair : higher precision and smaller heat-affected zone (suitable for high-value hooks).

  • AI wear prediction : Based on historical data training models, high-risk areas are warned in advance.

Summarize

✅Repairable  : Local wear within the limit → Surfacing/spraying + strict verification. ❌Unrepairable  : Cracks/deformation beyond the limit → Immediately stop use and scrap.

Technical Guide for Crane Hook Wear Detection and Repair

(covering testing methods, repair processes, scrapping standards , in compliance with GB/T 10051, EN 1677 and other standards)

1. Wear detection method

1. Conventional testing methods

Test items Tools and Methods Allowable wear limit
Increased opening Caliper measurement (compared to original size) ≤10% original size (oversize and scrapped)
Dangerous section wear Ultrasonic thickness gauge/caliper measurement ≤5% of the section thickness (scrap if exceeding the limit)
Local wear on the hook Magnetic particle testing (MT) or penetrant testing (PT) No cracks and wear ≤3mm
Thread wear Thread gauge inspection Effective thread engagement length ≥80%

2. Intelligent detection technology

  • 3D Scanning Imaging : Laser scanning reconstructs the wear profile with an accuracy of ±0.1mm.

  • Internet of Things (IoT) Monitoring :

    • Strain gauges + wireless transmission monitor stress changes in the wear area in real time.

    • Example: After installing sensors on the hooks of a port, the accuracy of wear warning increased by 90%.

2. Restoration Technology

1. Repairable conditions

  • Wear amount : does not exceed the scrap standard (opening ≤ 10%, wear ≤ 5%).

  • No cracks : No hidden defects found in magnetic particle inspection.

2. Repair process

(1) Surfacing repair

  • Applicable scenarios : local wear (such as hook tip, stress-bearing surface).

  • step :

    1. Surface treatment : Grinding to remove the oxide layer, cleaning with acetone.

    2. Preheating : 150~200℃ (to prevent cold cracks).

    3. Surfacing materials :

      • Low alloy steel welding wire (such as ER80S-D2, matching 34CrMo4 steel).

      • Stainless steel welding rods for marine environments (such as E309L).

    4. Post-processing :

      • Slow cooling + tempering (eliminating welding stress).

      • Machined to size (lathe/grinder).

(2) Metal spray repair

  • Applicable scenarios : large area uniform wear.

  • Process :

    • Arc spraying (material: FeCrNi alloy, coating thickness ≤ 2 mm).

    • Machining + polishing is required after spraying.

(3) Sleeve reinforcement

  • Applicable scenarios : thread wear or local damage to the hook neck.

  • method :

    • The worn areas are turned and inserted with high-strength alloy steel sleeves (interference fit).

3. Post-repair verification

  1. Non-destructive testing :

    • Secondary magnetic particle inspection (to confirm that there are no welding cracks).

  2. Mechanical testing :

    • Static load test : 1.25 times the rated load, suspended for 10 minutes (GB/T 10051).

    • Hardness test : The hardness of the repaired area must be consistent with that of the parent material (±10%).

4. Unrepairable scrapping standards

The product must be scrapped if any of the following conditions occur :

  • Cracks (of any length or depth).

  • The opening increases by >10% of the original size.

  • Dangerous section wear > 5% or local wear depth > 3mm.

  • Thread failure (stripping, breakage).

5. Preventive maintenance recommendations

  1. Regular inspection :

    • Visual inspection every shift and precision measurement every month.

  2. Lubrication and anti-wear :

    • Apply wear-resistant grease (such as molybdenum disulfide) to the wire rope contact surface .

  3. Environmental protection :

    • In corrosive environments, use galvanized hooks or spray anti-rust paint regularly.

6. Technology Trends

  • Laser cladding repair : higher precision and smaller heat-affected zone (suitable for high-value hooks).

  • AI wear prediction : Based on historical data training models, high-risk areas are warned in advance.

Summarize

✅Repairable  : Local wear within the limit → Surfacing/spraying + strict verification. ❌Unrepairable  : Cracks/deformation beyond the limit → Immediately stop use and scrap.

Technical Guide for Crane Hook Wear Detection and Repair

(covering testing methods, repair processes, scrapping standards , in compliance with GB/T 10051, EN 1677 and other standards)

1. Wear detection method

1. Conventional testing methods

Test items Tools and Methods Allowable wear limit
Increased opening Caliper measurement (compared to original size) ≤10% original size (oversize and scrapped)
Dangerous section wear Ultrasonic thickness gauge/caliper measurement ≤5% of the section thickness (scrap if exceeding the limit)
Local wear on the hook Magnetic particle testing (MT) or penetrant testing (PT) No cracks and wear ≤3mm
Thread wear Thread gauge inspection Effective thread engagement length ≥80%

2. Intelligent detection technology

  • 3D Scanning Imaging : Laser scanning reconstructs the wear profile with an accuracy of ±0.1mm.

  • Internet of Things (IoT) Monitoring :

    • Strain gauges + wireless transmission monitor stress changes in the wear area in real time.

    • Example: After installing sensors on the hooks of a port, the accuracy of wear warning increased by 90%.

2. Restoration Technology

1. Repairable conditions

  • Wear amount : does not exceed the scrap standard (opening ≤ 10%, wear ≤ 5%).

  • No cracks : No hidden defects found in magnetic particle inspection.

2. Repair process

(1) Surfacing repair

  • Applicable scenarios : local wear (such as hook tip, stress-bearing surface).

  • step :

    1. Surface treatment : Grinding to remove the oxide layer, cleaning with acetone.

    2. Preheating : 150~200℃ (to prevent cold cracks).

    3. Surfacing materials :

      • Low alloy steel welding wire (such as ER80S-D2, matching 34CrMo4 steel).

      • Stainless steel welding rods for marine environments (such as E309L).

    4. Post-processing :

      • Slow cooling + tempering (eliminating welding stress).

      • Machined to size (lathe/grinder).

(2) Metal spray repair

  • Applicable scenarios : large area uniform wear.

  • Process :

    • Arc spraying (material: FeCrNi alloy, coating thickness ≤ 2 mm).

    • Machining + polishing is required after spraying.

(3) Sleeve reinforcement

  • Applicable scenarios : thread wear or local damage to the hook neck.

  • method :

    • The worn areas are turned and inserted with high-strength alloy steel sleeves (interference fit).

3. Post-repair verification

  1. Non-destructive testing :

    • Secondary magnetic particle inspection (to confirm that there are no welding cracks).

  2. Mechanical testing :

    • Static load test : 1.25 times the rated load, suspended for 10 minutes (GB/T 10051).

    • Hardness test : The hardness of the repaired area must be consistent with that of the parent material (±10%).

4. Unrepairable scrapping standards

The product must be scrapped if any of the following conditions occur :

  • Cracks (of any length or depth).

  • The opening increases by >10% of the original size.

  • Dangerous section wear > 5% or local wear depth > 3mm.

  • Thread failure (stripping, breakage).

5. Preventive maintenance recommendations

  1. Regular inspection :

    • Visual inspection every shift and precision measurement every month.

  2. Lubrication and anti-wear :

    • Apply wear-resistant grease (such as molybdenum disulfide) to the wire rope contact surface .

  3. Environmental protection :

    • In corrosive environments, use galvanized hooks or spray anti-rust paint regularly.

6. Technology Trends

  • Laser cladding repair : higher precision and smaller heat-affected zone (suitable for high-value hooks).

  • AI wear prediction : Based on historical data training models, high-risk areas are warned in advance.

Summarize

✅Repairable  : Local wear within the limit → Surfacing/spraying + strict verification. ❌Unrepairable  : Cracks/deformation beyond the limit → Immediately stop use and scrap.

Pre: Specification for multi-machine collaborative operation of crane hooks
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