GB/T 18439-2001 Grab Bucket Technical Standard
GB/T 18439-2001 "Grabs for Lifting Appliances" is the general technical specification standard for crane grabs. It defines the technical requirements, test methods, and inspection rules for grabs used on cranes, and is applicable to all grab types matched with lifting equipment — ensuring proper grab-to-crane compatibility and safe, reliable grab performance.
Scope of Application and Standard Positioning
GB/T 18439-2001 serves as the companion technical specification to the product standard GB/T 10603-2015 "Grabs," focusing on general manufacturing and inspection requirements for grabs. The main structural components — shells, tie bars, and upper/lower cross beams — must be made of Q345B (≈S355J2) steel or higher grade. All welded joints are subject to Non-destructive testing in accordance with the weld quality level specified in the design requirements (UT sampling of critical welds ≥20%). Shell lip edges must be made of wear-resistant Alloy Steel (NM400 or NM500, hardness HB360–500), and hinge pins at all hinge points must be 40Cr or 42CrMo, quenched to HRC40–50.
Assembly requirements stipulate that all hinge points rotate freely (pins should turn by hand without noticeable binding), and the open-close synchronization of any two shells must not exceed 0.5 seconds difference in closing time. After closing, the maximum gap between shell lips must be ≤3mm for standard materials, or ≤5mm for lump materials with particle size >100mm. The centerline symmetry deviation of closed shells must be ≤5mm. The grab's Dead Weight deviation must not exceed ±5% of the design value.
Technical and Safety Requirements
The standard sets out systematic requirements for grab strength and safety: under static strength testing, the grab must be loaded to 1.25 times rated load, after which no permanent deformation or cracks may appear in any major load-bearing structural component (shells, tie bars, upper/lower cross beams). The test method involves closing the grab and applying a pulling force equal to 1.25 times the rated grab capacity (loading is applied via Wire Rope or Tie bars connected to the shell lip edges). Dynamic strength testing requires continuous open-close cycles of ≥20 at 1.1 times rated load, with no abnormal wear or cracks permitted on hinge pins or Weld Seams.
Safety factor requirements: the material Safety factor for all major load-bearing structural components must be ≥2.0 (relative to Yield Strength), and the shear Safety factor for all hinge pins must be ≥3.0 (relative to the pin material's shear strength). The Wire Rope diameter must match the rated grab capacity, with a wire rope Safety factor of ≥5. Each grab must have a Nameplate permanently affixed in a visible location (stating manufacturer, Model and Specification, rated grab capacity, Dead Weight, and date of manufacture) along with a safety operating instructions plate. Overload use of the grab is strictly prohibited.
Inspection Rules and Operation & Maintenance
The standard defines three levels of inspection: Factory Acceptance Test (unit-by-unit visual inspection, No-Load Test, and dimensional inspection), type test (conducted every 2 years, covering static strength, dynamic strength, and grab capacity tests), and sampling inspection (per GB/T 2828.1, general inspection level II, AQL=4.0). The grab capacity test under type test requires ≥10 grab cycles in standard test material, with the average actual grab volume calculated to be ≥90% of the rated capacity. The Wear Resistance test requires ≥500 consecutive grab cycles, after which the wear amount on the shell lip edges is measured.
The standard specifically classifies grabs as lifting equipment components closely related to personal safety. Non-Conforming Product must never leave the factory, and any grab failing any inspection item may not be repaired and resubmitted for inspection (direct disposal is required). During operation and maintenance, shell lip edge wear should be checked every 500 working hours; when lip height wear exceeds 50% of the original height, build-up Welding repair or replacement is required. Grease (lithium-based) should be injected through grease fittings into all hinge pins every 100 working hours. Pins and bushings must be replaced when the fit clearance exceeds 1.5 times the original clearance.
Standard Comparison and Application Recommendations
GB/T 18439-2001 and GB/T 10603-2015 "Grabs" are designed to be used together — the latter is the product standard (defining classification, types, and dimensional Parameters), while the former is the general technical specification (covering manufacturing process, material properties, and test methods). Grab manufacturing must comply with both standards simultaneously.
In grab selection, the rated grab capacity is designed around a specific material (typically standard sand and gravel with a Density of 1.6 t/m³). When switching to materials of different density (e.g., coal at 1.0 t/m³ or iron ore at 2.5 t/m³), a qualified person must recalculate the corresponding grab capacity, and the allowable grab weight must not be exceeded. On two-rope grabs, the open-close rope and Hoisting rope must be replaced at the same time, as differences in Wire Rope diameter deviation and flexibility between the two ropes can cause uneven shell open-close action. Kelude Heavy Industry supplies grabs and spare parts in all specifications.
Kelude Heavy Industry: Overhead & Gantry Crane Solutions
Kelude Heavy Industry specializes in the design and manufacture of heavy-duty overhead cranes and gantry cranes for industrial applications. Our product range covers single-girder and double-girder configurations, with capacities up to 300 tons and spans reaching 40 meters. We deliver reliable, high-performance lifting equipment tailored to demanding production environments.
Engineered for Performance and Safety
Every crane we produce is built to meet rigorous international standards, including ISO 4301 for crane classification and IEC 60204-32 for electrical equipment. Our engineering team focuses on key performance factors: duty cycle, lifting speed, and precise load control. Standard safety features include overload protection, limit switches, and emergency stop systems, ensuring safe operation even in continuous-use scenarios.
Customized Solutions for Diverse Industries
We understand that every facility has unique material-handling needs. Whether you require a low-headroom design for tight spaces, explosion-proof equipment for hazardous areas, or anti-sway technology for precise load positioning, our cranes can be customized to match your specifications. Industries we serve include steel processing, automotive manufacturing, warehousing, and power generation.
Technical Specifications at a Glance
The table below outlines the standard parameters for our overhead crane series. For custom projects, our engineers will work with you to define the optimal configuration based on your load requirements and operational conditions.
| Parameter | Standard Range |
|---|---|
| Lifting Capacity | 5 t – 300 t |
| Span Length | 10 m – 40 m |
| Lifting Height | 6 m – 30 m |
| Hoist Type | Wire rope / Chain hoist |
| Control Mode | Pendant / Remote / Cabin |
| Power Supply | 380 V / 50 Hz (customizable) |
Quality Assurance and Global Support
Our manufacturing facilities are ISO 9001 certified, and every crane undergoes rigorous load testing and inspection before shipment. We provide comprehensive documentation, including CE declarations and detailed operation manuals. With a global service network, we offer on-site installation, commissioning, and after-sales support to ensure your equipment operates at peak efficiency for years to come.
Frequently Asked Questions
Q: What is the lead time for a standard overhead crane?
A: Typical lead time for a standard single-girder crane is 6–8 weeks from order confirmation. Double-girder and custom-engineered cranes may require 10–12 weeks depending on complexity.
Q: Do you provide installation services?
A: Yes, our technical team can handle complete installation and commissioning on-site. We also offer operator training as part of our startup service package.
Q: Can you supply spare parts for existing cranes?
A: Absolutely. We stock a wide range of spare parts, including hoists, motors, brakes, and control panels. Contact our support team with your crane model and serial number for a quick quote.
Q: What warranty do you offer?
A: All our cranes come with a standard 12-month warranty covering manufacturing defects. Extended warranty options are available upon request.
Q: How do I request a quotation?
A: Simply send us your requirements—load capacity, span, lifting height, and duty cycle—via our website contact form or email. Our sales engineers will respond within 24 hours with a detailed proposal.
| Inspection Type | inspection items | technical requirements | Frequency |
|---|---|---|---|
| Factory Acceptance Test | Appearance+No-load+Dimension | unit by unit | Per Unit |
| type test | static load/dynamic load/Grabbing/Wear-Resistant | Per2Year | 1Frequency/2Year |
| Sampling Inspection | By GB/T 2828.1 | ⅡGrade AQL=4.0 | Batch |
| Daily Inspection | Cutting Edge Wear | ≤50%Original Height | Per500h |
| Safety Factor | Safety factor | inspection method | Standard |
|---|---|---|---|
| structural component Strength | ≥2.0 | 1.25Timesstatic load | §5.3 |
| hinge pin | ≥3.0(Shearing) | 1.1Timesdynamic load | §5.4 |
| Wire Rope | ≥5 | Breaking force | §5.5 |
| Grabbing Capacity | ≥90%Rated | Standard Material10Frequency | §5.5 |
Related Standards: GB/T 24810.1-2009 "Lifting Appliances — Brakes — Part 1: General Requirements" · GB/T 25120-2010 "Electric Hoists for Lifting Appliances"
Related Standards
Frequently Asked Questions
Q: What is the difference between GB/T 18439 and GB/T 10603 for grabs?
A: GB/T 10603-2015 "Grab" is a product standard — it defines classification, type dimensions, and the technical parameter series (the "what" standard). GB/T 18439-2001 "Grabs for Lifting Appliances" is a general technical specification — it focuses on manufacturing processes, material properties, and test methods (the "how" standard). The two complement each other; grab manufacturing must comply with both.
Q: Why is wear-resistant steel required for grab jaw blade edges?
A: Jaw blade edges come into direct contact with the material being handled, enduring high-stress cutting and abrasion. Standard structural steel (Q345B, HB150–200) typically lasts less than 500 hours when grabbing high-hardness materials like iron ore. Wear-resistant steel (NM400–NM500, HB360–500) offers 2–3 times the hardness of standard steel and delivers 5–10 times longer wear life.
Q: Why should the closing rope and hoisting rope of a two-rope grab be replaced at the same time?
A: The two wire ropes experience different load types — the closing rope primarily handles the tensile and impact loads of opening and closing the jaws, while the hoisting rope mainly carries static tensile loads. Replacing only one rope creates deviations in diameter, flexibility, and elongation between the two, causing uneven jaw operation and, in severe cases, grab skewing and material spillage.
Q: How often should the hinge pins on a grab be replaced?
A: Hinge pins should be replaced when the clearance exceeds 1.5 times the original fit, or when fatigue spalling appears on the pin surface. Inspection every 2,000 operating hours is recommended. Properly lubricated hinge pins can last 2–3 times longer. Kelude Heavy Industry supplies grabs and spare parts in all specifications.
