GB/T 10051.4 Lifting Hook Lock Nut Standard Explained
GB/T 10051.4 — Lifting Hook and Hook Nut Standard is a key technical specification in the crane industry. Developed by the national standardization authority, it defines the requirements for lifting hook nuts used in crane applications.
The standard provides a unified technical basis for design engineers, inspection bodies, and end users. Kelude strictly follows its technical requirements throughout product development and manufacturing to ensure compliance and operational reliability.
Application Scope and Positioning
GB/T 10051.4 specifies the technical requirements and safety indicators for lifting hooks and hook nuts on cranes, covering all types of lifting appliances with a rated lifting capacity above 0.5 t. The standard governs not only the design and manufacturing of new equipment but also provides clear technical guidance for the inspection, maintenance, and retrofit of in-service units. 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 specification framework.
Core Technical Parameters
Under GB/T 10051.4, the design and manufacture of lifting hooks and hook nuts must satisfy a stringent set of core technical parameters. These values are established from extensive test data and safety engineering principles, covering the full spectrum from material selection to structural design. The safety factor ranges specified in the standard account for fatigue life and limit load conditions under demanding operating environments.
Key Parameter Comparison and Analysis
| Item | technical requirements | Description |
|---|---|---|
| Material | 45Steel Grade(quenching and tempering)/40Cr(quenching and tempering) | Yield≥640MPa |
| Properties Grade | 10.9Class(With Bolt Matching) | Hardness HRC32~39 |
| Thread Specification | Metric Coarse Thread6H | relief groovestress concentration Zone |
| Locking Measures | Cotter Pin/Lock Washer/Lock Nut | Dual Nut Locking Priority |
| Non-destructive testing | MTMagnetic Particle100% | relief groove+Thread Root |
| Preload Torque | Per GB/T 1231Standard | Final Tightening Torque Method |
Inspection Requirements and Intervals
Factory Acceptance Tests are performed on every unit by the quality inspection department at the manufacturer's facility. Each unit that passes inspection ships with a detailed inspection report and a Certificate of Conformity. Type Tests are conducted when a new product enters production, when manufacturing moves to a different facility, or when significant structural changes are introduced. For equipment already in service, the periodic inspection interval is determined by the work duty classification and operating environment, and generally does not exceed 12 months.
| Item | technical requirements | Description |
|---|---|---|
| Magnetic Particle Testing (MT) | relief groove/Thread Root | Annual+Detection Crack Discard |
| Thread Inspection | Wear/Deformation/Thread Stripping | Quarterly+Replace Upon Detection |
| Locking Components | Cotter Pin/Lock Washer Status | Monthly+Intact and Functional |
| Marking | Grade/Specification/Date | Permanently Visible |
Safe Operation & Management Requirements
The standard places strong 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, usage, maintenance, and inspection records.
FAQ: Hook Nut Standards & Inspection
Q: What are the material requirements for hook nuts under GB/T 10051.4?
A: Grade 45 steel with quenching and tempering, or 40Cr with quenching and tempering. Minimum yield strength of 640 MPa. Property class 10.9.
Q: What locking devices are required for hook nuts under GB/T 10051.4, and how should they be inspected?
A: Cotter pin, lock washer, or double nut. Double-nut locking is the preferred method. Monthly inspections must confirm all locking devices are intact and functional.
Q: What are the Non-destructive testing coverage requirements and inspection intervals for hook nuts under GB/T 10051.4?
A: Magnetic Particle Testing (MT) must achieve 100% coverage of the relief groove and thread root. Annual inspections are required; any crack detected mandates immediate replacement.
Q: What marking and identification requirements apply to hook nuts under GB/T 10051.4?
A: Property class, specification, and manufacturing date must be permanently and legibly marked. Markings must be reapplied whenever the nut is replaced.
Kelude Heavy Industry — Specialized in crane design and manufacturing, fully compliant with the GB/T 10051.4 standard system, offering full lifecycle service.
