GB/T 5972 Wire Rope Discard Criteria Explained
GB/T 5972 Wire Rope Discard Standard is a key technical specification in the crane industry. Developed by the national standards committee, it defines the inspection and discard criteria for crane wire ropes.
The standard provides a unified technical basis for design personnel, inspection bodies, and end users. Kelude strictly adheres to its requirements throughout the product development and manufacturing process.
Scope and Application of the Standard
GB/T 5972 Wire Rope Discard Standard specifies the technical requirements and safety indicators for the discard criteria of crane wire ropes. It applies to all types of lifting appliances with a Rated Lifting Capacity above 0.5 t. The standard covers not only the design and manufacturing of new equipment but also provides clear technical guidance for the inspection, maintenance, and modification of in-service machinery. As a critical component of the crane standard system, it aligns with the EN 13001 Crane Safety Standard series and ISO 4309 Wire Rope Inspection Standard, forming a comprehensive technical framework. The core technical parameters and Safety factor requirements defined in the standard give design personnel a clear design basis and provide third-party inspection bodies with quantifiable acceptance criteria for Type Test and Factory Acceptance Test procedures.
Core Technical Parameters and Requirements
Under GB/T 5972, the design and manufacturing of wire rope discard criteria must satisfy a stringent set of technical parameters. These values are established through extensive test data and safety engineering principles, covering the entire process from material selection to structural design. The Safety factor ranges specified in the standard account for the fatigue life and limit load conditions of lifting appliances in demanding operating environments. In engineering practice, design personnel must translate these requirements into concrete design parameters to ensure that the load capacity of every component meets the safety requirements.
Comparative Analysis of Key Technical Parameters
| Item | technical requirements | Description |
|---|---|---|
| Diameter Reduction | >7%nominal diameter Discard | Mean Vertical Diameter Measurement on Unloaded Straight Section |
| Number of broken wires | 1lay length>10%Total Number of Wires(regular lay) | Lang lay>5%Discard |
| Corrosion Grade | 3Grade(Severe Corrosion+Pitting)Discard Immediately | 1Light Grade/2Medium Grade/3Severe Grade |
| Kinking/Strand Extrusion | Discard Upon Detection | Non-Repairable |
| Inspection Interval | A1~A5Monthly Visual Inspection/Quarterly Electromagnetic | A6~A8Monthly Visual Inspection+Electromagnetic |
| Lubrication | Indoor Bimonthly/Outdoor Monthly | Compatible with Manufacturer |
Inspection Requirements and Intervals
GB/T 5972 sets forth explicit requirements for Factory Acceptance Test, Type Test, and periodic inspection regarding wire rope discard criteria. Factory Acceptance Test shall be conducted on each individual unit by the quality inspection department at the manufacturer's facility, and equipment that passes inspection shall be accompanied by a detailed inspection report and a certificate of conformity. Type Test is performed when a new product enters initial production, when manufacturing is transferred to another facility, or when major structural changes occur. The periodic inspection interval for in-service equipment is determined based on work duty and operating environment, generally not exceeding 12 months. For heavy-duty cranes operating continuously at A7 to A8 classification levels, the inspection interval shall be shortened to 6 months as appropriate.
| Item | technical requirements | Description |
|---|---|---|
| visual inspection | Full-Length Surface Rust/wire break/Deformation | Outdoor Monthly+Critical Zones |
| Diameter Measurement | vernier caliper0.02mm | Outdoor Monthly+Mean Vertical Diameter Measurement on Unloaded Straight Section |
| Electromagnetic Detection | Wire Rope Tester (WRT)LMA+LF | A5Quarterly/A6Outdoor Monthly |
| Lubrication Condition | Surface Lubrication/Core Lubrication | Indoor Bimonthly+Replenish if Insufficient |
Safe Operation and Management Requirements
Under the implementation of GB/T 5972, safe operation and routine management play a critical role. The Standard places particular emphasis on operator qualification and training, requiring that all operators complete specialized training and obtain the necessary certifications before being allowed to work. User units must establish a comprehensive equipment file management system that documents the full lifecycle of the equipment, including installation, operation, maintenance, and inspection. Any safety hazard identified must be addressed through the rectification procedure specified in the Standard to ensure the equipment remains safe and controllable at all times. Additionally, the Standard imposes restrictive requirements on equipment use under extreme operating conditions.
Frequently Asked Questions
Q: What are the discard criteria for wire rope under GB/T 5972?
A: The rope must be discarded if any of the following conditions is met: diameter reduction exceeding 7%, wire breaks exceeding 10% of the total, corrosion reaching Grade 3, or kinking/core protrusion.
Q: What are the electromagnetic testing requirements?
A: LMA detection sensitivity must be ≥2%, with a testing speed of 0.3–1.5 m/s. Calibration is required prior to testing.
Q: How do inspection intervals differ?
A: Grades A1 to A5 require monthly visual inspection plus quarterly electromagnetic testing. Grades A6 to A8 require monthly visual inspection plus electromagnetic testing. Outdoor equipment requires more frequent inspection.
Q: What are the lubrication requirements?
A: Indoor equipment requires lubrication every two months, while outdoor equipment requires monthly lubrication. Lubricants must be compatible with the manufacturer's recommendations.
Kelude Heavy Industry — Specialized in crane design and manufacturing, with products strictly compliant with the GB/T 5972 standard system.
