Inspection | Crane Inspection Standards and Methods

1. Inspection classification and implementation requirements

1. Inspection category system

• Visual inspection: covers the appearance and structural integrity inspection of all visible parts

• Parameter measurement: Use precision instruments to quantitatively test 32 key operating parameters

• Load test: includes 5 progressive test stages (no load → rated load → static load → dynamic load → stability)

• Noise test: Sound pressure level measurement according to ISO 4871 standard

2. Sampling management specifications

• Mass production sampling:

  • First unit mandatory inspection + 3% batch random inspection

  • 100% full inspection for special models

• Single customized equipment:

  • On-site inspection in stages

  • Key node witness testing

3. Testing equipment requirements

• Measuring instruments:

  • Laser rangefinder accuracy ±1mm

  • Torque wrench accuracy ±3%

  • Vibration analyzer bandwidth 0-10kHz

• Loading device:

  • Standard test block accuracy ±0.5%

  • Electronic crane scale grade OIML R60 Class III

2. Visual Inspection Technical Standards

1. Structural parts inspection

• Metal Structure:

  • Weld UT inspection coverage ≥ 20%

  • High-strength bolt torque deviation ≤±5%

  • Corrosion area ≤ 5% of component surface area

• Mechanical components:

  • The number of broken wires in the wire rope is less than 10% of the total number of wires

  • Wear of pulley groove bottom ≤ 20% of wall thickness

  • Brake pad thickness ≥ 50% of original thickness

2. Safety device verification

• Electrical system:

  • Insulation resistance ≥ 1MΩ (1000V megohmmeter)

  • Emergency stop button response time ≤ 0.5s

• Limit device:

  • Lifting limit repeatability accuracy ±50mm

  • Stroke limiter action error ≤1%

3. Key points for document review

• Technical Documents:

  • Design calculation report (FEA report)

  • Material certification (mechanical properties testing)

  • Welding Procedure Qualification (WPS/PQR)

• Qualification documents:

  • Special equipment manufacturing license

  • Nondestructive testing personnel qualifications

  • Explosion-proof certification (applicable occasions)

3. Performance parameter testing standards

1. Motion parameter measurement

• Speed characteristics:

  • Hoisting speed deviation ≤ nominal value ±5%

  • Trolley travel synchronization error ≤ 2%

  • Rotation speed fluctuation rate ≤ 3%

• Positioning accuracy:

  • Repeat positioning error ±10mm

  • Braking slip ≤ 1% of travel

2. Structural parameter verification

• Geometric dimensions:

  • Span tolerance ±5mm (L≤30m)

  • Wheelbase deviation ≤±3mm

  • Track straightness ≤1/1000

3. Safety clearance check

• Minimum safety distance:

  • Swing allowance ≥300mm

  • Electrical clearance ≥10mm

  • Maintenance channel width ≥500mm

4. Load test specifications

1. Grading test procedures

• No-load test:

  • The entire process of each institution should take ≥ 5 minutes

  • Control system response testing

• Rated load test:

  • 3 complete operating cycles under 100% Pn conditions

  • Structural deformation monitoring (strain gauge arrangement)

2. Ultimate load test

• Static load test:

  • 125% PN hover for 10 minutes

  • Permanent deformation ≤0.1%L

• Dynamic load test:

  • 110%Pn impact load test

  • Braking deceleration 0.2-0.5m/s²

3. Stability verification

• Overturning test:

  • The most unfavorable working condition combination

  • Safety factor ≥ 1.25 (GB/T 3811)

  • Leg settlement ≤5mm

5. Special testing items

1. Fatigue performance evaluation

• Stress testing:

  • Hot spot strain measurement

  • Dynamic stress amplitude recording

• Life expectancy prediction:

  • Calculation based on Miner's criterion

  • FAT level verification of key welds

2. Environmental adaptability

• Climate testing:

  • -20℃ low temperature start

  • 50℃ high temperature continuous operation

• Corrosion testing:

  • Salt spray test ≥500h

  • Coating thickness ≥120μm

3. Intelligent functional verification

• Automated testing:

  • Positioning accuracy ±5mm

  • Anti-sway control (residual swing angle ≤ 1°)

• Remote Monitoring:

  • Data refresh rate ≥ 1Hz

  • Fault diagnosis accuracy ≥95%

6. Inspection Document System

1. Report preparation requirements

• Data Records:

  • Original data retention ≥ 10 years

  • Key Test Video Archive

• Conclusion

  • According to GB/T 5905-2023

  • Principles for determining the eligibility of each item

2. Certification mark

• Compulsory certification:

  • TSG Q7002-2019

  • CE certification (EN 13000)

• Voluntary certification:

  • ISO 4310

  • AWS D14.1

Implementation of this specification requires compliance with the Crane Design Specification (GB/T 3811-2008). For ultra-large cranes (lifting capacity ≥ 100t), additional wind load testing (according to EN 1991-1-4) and seismic analysis should be performed. It is recommended that a digital inspection system be used to enable real-time upload and AI-powered analysis of inspection data.