News

Home > Technology

Limit load test method for crane hook

2025-07-29 02:53:04

The ultimate load test of the crane hook is the core link to verify its safety performance, which must strictly follow international standards (such as ISO 17096, ASME B30.10) or national standards (GB/T 10051.3). The following are professional test methods and key control points:

1. Test Standards and Grading

  1. Test Type

    • Static load test : Verify structural strength (usually 1.5~2 times the rated load)

    • Dynamic load test : simulates actual working condition fatigue (cyclic loading until failure)

    • Destructive testing : Determine the ultimate load-bearing capacity (for scientific research or new product certification)

  2. Test level (taking GB/T 10051.3 as an example)

    Test level Load multiple Duration Eligibility criteria
    Factory test 1.25x 10 minutes No permanent deformation
    Type test 2.0x 30 minutes No cracks
    Limit Testing ≥2.5x to fracture Record failure load

2. Test equipment and tooling

  1. Core equipment

    • Hydraulic loading system : accuracy ±1% (e.g. 500 ton hydraulic cylinder)

    • Strain measurement system : patch location is inside the hook body (dangerous section)

    • Deformation monitoring : laser displacement sensor (accuracy 0.01mm)

    • Non-destructive testing equipment : MT/UT testing is required before and after testing

  2. Tooling design

    • The test bench must meet the following requirements:

      • Rigid support (rigidity ≥ 10 times the rigidity of the hook being tested)

      • Load centering error ≤1° (to prevent eccentric loading)

    • Example configuration:

      plaintext 
      Loading chain → Force sensor → Hook → Simulated beam → Hydraulic actuator

3. Static load test process (key steps)

  1. Preloading

    • Apply 10% of the rated load and eliminate the assembly gap for 2 minutes.

  2. Staged loading

    stage Load ratio Keep time Monitoring Project
    1 50% 3 minutes Strain uniformity
    2 100% 5 minutes Hook deformation
    3 125% 10 minutes Weld integrity
    4 150%~200% Until failure Crack initiation point

  3. Qualification

    • Measure permanent deformation after unloading: the increase in hook opening is ≤0.25% of the original size

    • No cracks visible to the naked eye (re-inspection with a 20x magnifying glass is required)

4. Dynamic load fatigue test method

  1. Test Parameters

    • Load spectrum: simulates actual working conditions (such as 0~80% rated load alternating)

    • Frequency: ≤5Hz (to avoid heat accumulation affecting material properties)

    • Termination conditions:

      • Cracks ≥3mm appear

      • The number of cycles reaches the standard value (such as 100,000 times as specified in ISO 4309)

  2. Data collection

    • SN curve drawing: recording the relationship between crack initiation cycle and stress amplitude

    • Fracture analysis: Scanning electron microscope (SEM) observation of fatigue striations

5. Key points of destructive limit test

  1. Loading Control

    • Rate: ≤10MPa/s (to prevent impact effect)

    • Termination: Load drops to 10% of peak force (considered as failure)

  2. Failure Mode Analysis

    Failure type feature Improvement direction
    Plastic fracture Obvious necking, fibrous fracture Improve material elongation
    Brittle fracture Smooth fracture, radial pattern Optimizing heat treatment processes
    fatigue fracture Conchoidal striations Improved stress concentration design

6. Safety Protection and Reporting

  1. Protective measures

    • The test area is equipped with explosion-proof walls (withstanding ≥200% impact energy)

    • Remote monitoring operation (minimum safety distance ≥ 3 times the hook size)

  2. Test report contents

    • Load-deformation curve

    • Failure location coordinates (such as the root of the hook handle thread)

    • Comparative analysis with standard limits

7. Industry-specific requirements

  • Ship hoisting : additional salt spray corrosion test is required (such as DNVGL-ST-0378)

  • Nuclear power hook : required to withstand LOCA (loss of coolant accident) condition simulation

  • Aerospace : -55°C ~ 150°C temperature gradient testing is required

Precautions

  1. The testing organization must have CNAS/ILAC certification qualifications;

  2. Sampling ratio of the same batch:

    • Conventional test ≥3%

    • Type test 100%;

  3. After testing the samples must be permanently marked (e.g. laser engraved "TESTED").

Through scientific extreme load testing, the failure boundary of the hook can be accurately evaluated, providing data support for selection and safe use. It is recommended that companies establish a test database and conduct life prediction in conjunction with actual working conditions.

The ultimate load test of the crane hook is the core link to verify its safety performance, which must strictly follow international standards (such as ISO 17096, ASME B30.10) or national standards (GB/T 10051.3). The following are professional test methods and key control points:

1. Test Standards and Grading

  1. Test Type

    • Static load test : Verify structural strength (usually 1.5~2 times the rated load)

    • Dynamic load test : simulates actual working condition fatigue (cyclic loading until failure)

    • Destructive testing : Determine the ultimate load-bearing capacity (for scientific research or new product certification)

  2. Test level (taking GB/T 10051.3 as an example)

    Test level Load multiple Duration Eligibility criteria
    Factory test 1.25x 10 minutes No permanent deformation
    Type test 2.0x 30 minutes No cracks
    Limit Testing ≥2.5x to fracture Record failure load

2. Test equipment and tooling

  1. Core equipment

    • Hydraulic loading system : accuracy ±1% (e.g. 500 ton hydraulic cylinder)

    • Strain measurement system : patch location is inside the hook body (dangerous section)

    • Deformation monitoring : laser displacement sensor (accuracy 0.01mm)

    • Non-destructive testing equipment : MT/UT testing is required before and after testing

  2. Tooling design

    • The test bench must meet the following requirements:

      • Rigid support (rigidity ≥ 10 times the rigidity of the hook being tested)

      • Load centering error ≤1° (to prevent eccentric loading)

    • Example configuration:

      plaintext 
      Loading chain → Force sensor → Hook → Simulated beam → Hydraulic actuator

3. Static load test process (key steps)

  1. Preloading

    • Apply 10% of the rated load and eliminate the assembly gap for 2 minutes.

  2. Staged loading

    stage Load ratio Keep time Monitoring Project
    1 50% 3 minutes Strain uniformity
    2 100% 5 minutes Hook deformation
    3 125% 10 minutes Weld integrity
    4 150%~200% Until failure Crack initiation point

  3. Qualification

    • Measure permanent deformation after unloading: the increase in hook opening is ≤0.25% of the original size

    • No cracks visible to the naked eye (re-inspection with a 20x magnifying glass is required)

4. Dynamic load fatigue test method

  1. Test Parameters

    • Load spectrum: simulates actual working conditions (such as 0~80% rated load alternating)

    • Frequency: ≤5Hz (to avoid heat accumulation affecting material properties)

    • Termination conditions:

      • Cracks ≥3mm appear

      • The number of cycles reaches the standard value (such as 100,000 times as specified in ISO 4309)

  2. Data collection

    • SN curve drawing: recording the relationship between crack initiation cycle and stress amplitude

    • Fracture analysis: Scanning electron microscope (SEM) observation of fatigue striations

5. Key points of destructive limit test

  1. Loading Control

    • Rate: ≤10MPa/s (to prevent impact effect)

    • Termination: Load drops to 10% of peak force (considered as failure)

  2. Failure Mode Analysis

    Failure type feature Improvement direction
    Plastic fracture Obvious necking, fibrous fracture Improve material elongation
    Brittle fracture Smooth fracture, radial pattern Optimizing heat treatment processes
    fatigue fracture Conchoidal striations Improved stress concentration design

6. Safety Protection and Reporting

  1. Protective measures

    • The test area is equipped with explosion-proof walls (withstanding ≥200% impact energy)

    • Remote monitoring operation (minimum safety distance ≥ 3 times the hook size)

  2. Test report contents

    • Load-deformation curve

    • Failure location coordinates (such as the root of the hook handle thread)

    • Comparative analysis with standard limits

7. Industry-specific requirements

  • Ship hoisting : additional salt spray corrosion test is required (such as DNVGL-ST-0378)

  • Nuclear power hook : required to withstand LOCA (loss of coolant accident) condition simulation

  • Aerospace : -55°C ~ 150°C temperature gradient testing is required

Precautions

  1. The testing organization must have CNAS/ILAC certification qualifications;

  2. Sampling ratio of the same batch:

    • Conventional test ≥3%

    • Type test 100%;

  3. After testing the samples must be permanently marked (e.g. laser engraved "TESTED").

Through scientific extreme load testing, the failure boundary of the hook can be accurately evaluated, providing data support for selection and safe use. It is recommended that companies establish a test database and conduct life prediction in conjunction with actual working conditions.

The ultimate load test of the crane hook is the core link to verify its safety performance, which must strictly follow international standards (such as ISO 17096, ASME B30.10) or national standards (GB/T 10051.3). The following are professional test methods and key control points:

1. Test Standards and Grading

  1. Test Type

    • Static load test : Verify structural strength (usually 1.5~2 times the rated load)

    • Dynamic load test : simulates actual working condition fatigue (cyclic loading until failure)

    • Destructive testing : Determine the ultimate load-bearing capacity (for scientific research or new product certification)

  2. Test level (taking GB/T 10051.3 as an example)

    Test level Load multiple Duration Eligibility criteria
    Factory test 1.25x 10 minutes No permanent deformation
    Type test 2.0x 30 minutes No cracks
    Limit Testing ≥2.5x to fracture Record failure load

2. Test equipment and tooling

  1. Core equipment

    • Hydraulic loading system : accuracy ±1% (e.g. 500 ton hydraulic cylinder)

    • Strain measurement system : patch location is inside the hook body (dangerous section)

    • Deformation monitoring : laser displacement sensor (accuracy 0.01mm)

    • Non-destructive testing equipment : MT/UT testing is required before and after testing

  2. Tooling design

    • The test bench must meet the following requirements:

      • Rigid support (rigidity ≥ 10 times the rigidity of the hook being tested)

      • Load centering error ≤1° (to prevent eccentric loading)

    • Example configuration:

      plaintext 
      Loading chain → Force sensor → Hook → Simulated beam → Hydraulic actuator

3. Static load test process (key steps)

  1. Preloading

    • Apply 10% of the rated load and eliminate the assembly gap for 2 minutes.

  2. Staged loading

    stage Load ratio Keep time Monitoring Project
    1 50% 3 minutes Strain uniformity
    2 100% 5 minutes Hook deformation
    3 125% 10 minutes Weld integrity
    4 150%~200% Until failure Crack initiation point

  3. Qualification

    • Measure permanent deformation after unloading: the increase in hook opening is ≤0.25% of the original size

    • No cracks visible to the naked eye (re-inspection with a 20x magnifying glass is required)

4. Dynamic load fatigue test method

  1. Test Parameters

    • Load spectrum: simulates actual working conditions (such as 0~80% rated load alternating)

    • Frequency: ≤5Hz (to avoid heat accumulation affecting material properties)

    • Termination conditions:

      • Cracks ≥3mm appear

      • The number of cycles reaches the standard value (such as 100,000 times as specified in ISO 4309)

  2. Data collection

    • SN curve drawing: recording the relationship between crack initiation cycle and stress amplitude

    • Fracture analysis: Scanning electron microscope (SEM) observation of fatigue striations

5. Key points of destructive limit test

  1. Loading Control

    • Rate: ≤10MPa/s (to prevent impact effect)

    • Termination: Load drops to 10% of peak force (considered as failure)

  2. Failure Mode Analysis

    Failure type feature Improvement direction
    Plastic fracture Obvious necking, fibrous fracture Improve material elongation
    Brittle fracture Smooth fracture, radial pattern Optimizing heat treatment processes
    fatigue fracture Conchoidal striations Improved stress concentration design

6. Safety Protection and Reporting

  1. Protective measures

    • The test area is equipped with explosion-proof walls (withstanding ≥200% impact energy)

    • Remote monitoring operation (minimum safety distance ≥ 3 times the hook size)

  2. Test report contents

    • Load-deformation curve

    • Failure location coordinates (such as the root of the hook handle thread)

    • Comparative analysis with standard limits

7. Industry-specific requirements

  • Ship hoisting : additional salt spray corrosion test is required (such as DNVGL-ST-0378)

  • Nuclear power hook : required to withstand LOCA (loss of coolant accident) condition simulation

  • Aerospace : -55°C ~ 150°C temperature gradient testing is required

Precautions

  1. The testing organization must have CNAS/ILAC certification qualifications;

  2. Sampling ratio of the same batch:

    • Conventional test ≥3%

    • Type test 100%;

  3. After testing the samples must be permanently marked (e.g. laser engraved "TESTED").

Through scientific extreme load testing, the failure boundary of the hook can be accurately evaluated, providing data support for selection and safe use. It is recommended that companies establish a test database and conduct life prediction in conjunction with actual working conditions.

Pre: Specification for multi-machine collaborative operation of crane hooks
Next: Analysis of factors affecting the price of crane hooks

Inquiry

Please leave us your requirements, we will contact you soon.

  • *
  • *
  • *
  • *