GB/T 20062-2017 Mobile Crane Reliability Test Standard
Test Conditions and Procedures
GB/T 20062-2017 specifies the operating reliability test conditions for mobile cranes: the test site must be level and firm, with wind speed ≤13 m/s. The test load is set at 100% of the rated lifting capacity, and the cumulative operating time must reach at least 500 hours. The test covers all crane motions, including hoisting, lowering, slewing, luffing, and travel.
During the test, data such as fault time, location, and mode are recorded and classified as inherent faults or misuse faults. The reliability assessment indicators require a mean time between failures (MTBF) of ≥150 hours and an operational success rate of ≥90%.
Fault Classification and Data Analysis
Inherent faults—failures caused by defects in product design and manufacturing—are included in the MTBF calculation. Examples include cracks in structural components, hydraulic system leaks, and electrical component failures. Misuse faults—failures resulting from improper operation or inadequate maintenance—are excluded from MTBF but must be recorded and analyzed. Secondary faults—failures triggered by other faults—are also excluded from MTBF. If the same component fails three or more times consecutively, it is deemed a design defect and the test is terminated.
After the test, non-destructive testing is performed on the main structure to confirm the absence of cracks and permanent deformation. The standard provides a systematic classification of faults: inherent faults refer to failures caused by design or manufacturing defects and are included in the MTBF calculation. Examples include cracks in structural components, hydraulic system leaks, electrical component failures, and premature aging of seals.
Misuse faults refer to failures caused by improper operation or poor maintenance—such as overload, failure to follow maintenance schedules, or operational errors leading to collisions. These are excluded from MTBF but must be recorded for analysis and improvement. Secondary faults refer to failures triggered by other faults—for example, damage to a hydraulic pump caused by a ruptured hydraulic pipeline. These are also excluded from MTBF but the fault chain must be documented.
The standard requires that a fault analysis be conducted within 2 hours of each fault occurrence, with details recorded in the fault record table (time, location, mode, cause, and classification). After 500 hours of cumulative operation, the MTBF is calculated, and the operational success rate is determined—the ratio of successfully completed work cycles to total work cycles must be ≥90%. Following the test, non-destructive testing is performed on the main structure to confirm the absence of cracks and permanent deformation.
If the same component fails three or more times consecutively, it is deemed a design defect and the test is terminated.
| reliability Indicator | technical requirements | test method | Determination |
|---|---|---|---|
| MTBF | ≥150h | Accumulated Operation | inherent fault Calculation |
| Completed Power | ≥90% | Full Cycle | All Completed |
| inherent fault | ≤3Times/500h | Recording and Statistics | Exclusion of Misuse/Subordinate |
| Structural Condition | None Crack/Deformation | Non-destructive testing | Test Before-and-After Comparison |
Test Report & Assessment
The Test Report must include product information, test conditions (temperature, humidity, wind speed, Load spectrum), test data (operating hours, duty cycles, fault record table), MTBF calculation process and results, fault analysis (fault tree or root cause analysis), improvement suggestions, and the final assessment conclusion.
Testing must be terminated immediately in the event of a personal safety incident, three or more consecutive faults at the same component, or when the MTBF falls significantly below the target value with no realistic prospect of improvement.
The Test Report shall contain the following complete information — product details (model, serial number, factory date, key Parameters), test conditions (site, temperature, humidity, wind speed, Load spectrum), test data (operating hours, duty cycles, fault record table), MTBF calculation process and results, fault analysis (fault tree or root cause analysis), improvement suggestions, and the final assessment conclusion.
The report must be signed by the test supervisor and stamped with the official seal of the testing organization, with a retention period of no less than 10 years. The standard specifies the conditions for terminating a test — immediate termination upon a personal safety incident; termination upon three or more consecutive faults at the same component, which indicates a design Defect; and termination when the MTBF is significantly below the target value with no possibility of improvement. After termination, an interim Test Report shall be issued documenting the reason for termination and the cumulative test data.
Products that fail the test must undergo design improvements and then repeat the reliability test until all Indicator requirements are met. Kelude can provide Mobile Crane reliability testing services according to the standard.
| Fault Classification | Definition | Inclusion Criteria MTBF | Example |
|---|---|---|---|
| inherent fault | design Defect | Yes | Crack/Leakage |
| misuse fault | Improper Operation | No | overload/Collision |
| secondary fault | Secondary Inducement | No | Chain Reaction |
| Shutdown Due to Electrical Fault | maintenance Defective | No | Lubrication Insufficient |
FAQ
Q: How is the MTBF indicator calculated?
A: MTBF = total test time / number of inherent faults. The standard requires MTBF ≥ 150h. For example, if 3 inherent faults occur over 600h of cumulative operation, the MTBF is 200h, which passes. An inherent fault is a failure caused by design or manufacturing defects. Misuse faults (improper operation) and secondary faults (triggered by another failure) are not counted.
Q: How is the load spectrum for the reliability test determined?
A: Light load (≤30% of rated capacity, 40% of the time), medium load (30%–70%, 35%), and heavy load (70%–100%, 25%). The cycle includes all motions: hoisting/lifting, lowering, slewing, and luffing. The total test duration is ≥500h.
Q: What happens if a fault occurs during the test?
A: Record the time, location, mode, and cause of the fault. The test may resume after replacing the failed part; replacement time is not counted. If the same fault recurs 3 or more times at the same location, it is deemed a design defect, and the test is terminated with a failing result.
Q: What must be included in the test report?
A: Product model, test conditions/load spectrum, total test time, MTBF calculation process, fault record table, fault analysis conclusions, and improvement suggestions. The final verdict — pass or fail — must be stated along with the justification.
