GB/T 10603-2015 Grab Crane Bucket Standard Guide
GB/T 10603-2015 "Grab Buckets" is the general product standard for crane grabs. It specifies the classification, technical requirements, test methods, and inspection rules for grab buckets, and is applicable to the manufacturing and acceptance of all types of crane grabs, including double-rope, single-rope, hydraulic, and electric grabs.
GB/T 10603-2015 is the general technical standard for grab buckets, defining their classification, technical requirements, test methods, and inspection rules. As the core load-handling device for bulk material handling, grabs are widely used in port, power plant, and metallurgical operations for material handling tasks.
Grab Classification and Structural Types
GB/T 10603-2015 classifies grabs by drive mode: Double-rope grabs — two wire ropes independently control the opening/closing and hoisting actions. This type offers a simple, reliable structure and is the most widely used grab configuration. Single-rope grabs — one wire rope handles both opening/closing and hoisting through a special mechanical locking mechanism that switches between the two actions at set positions. These are suitable for simple cranes with a single drum. Hydraulic grabs — hydraulic cylinders drive the shell opening/closing, delivering high gripping force with precise control. These are ideal for handling large or hard materials. Electric grabs — a built-in electric hoist winch or electric linear actuator drives the opening/closing action without requiring external wire rope coordination, making them suitable for dedicated grab cranes. By shell count, grabs are divided into two-shell grabs (two symmetrical shells, the most common type for bulk handling) and multi-shell grabs (4–8 shells arranged in a rosette pattern, designed for large ore, scrap steel, and logs). By material density, grabs are classified as light-duty (for materials with density ≤1.2 t/m³, such as coal and grain), medium-duty (density 1.2–2.0 t/m³, such as sand, gravel, and ore), and heavy-duty (density ≥2.0 t/m³, such as iron ore and steel slag).
Technical Parameters and Selection
Key technical parameters specified in the standard include: Rated volume — the effective internal volume of the grab in the closed position, expressed in m³. Rated capacity — the rated weight of material the grab can handle in a single cycle, expressed in tons, typically equal to the grab's dead weight plus the rated material weight. Grab dead weight — the weight of the grab itself, a significant component of the crane's lifting capacity. The grab ratio (weight of material grabbed divided by grab dead weight) is the core efficiency indicator: double-rope grabs typically achieve a ratio of 1.5–2.5, while hydraulic grabs can reach 2.5–4.0. Maximum opening width — the greatest horizontal distance between the shell tips when the grab is fully open, determining the grab's reach within the material pile and the working space required for the supporting crane. Closed height — the overall height of the grab when fully closed, which affects the crane's minimum lifting height. The standard recommends a series of grab volumes (0.5 m³, 0.75 m³, 1.0 m³, 1.5 m³, 2.0 m³, 2.5 m³, 3.0 m³, 4.0 m³, 5.0 m³, 6.0 m³, 8.0 m³, and 10.0 m³ — 12 sizes in total). Users should select the appropriate grab volume based on material density and crane lifting capacity.
Materials and Structural Strength
The standard specifies the following material and structural strength requirements: Shell material — grab shells must be made of high-strength wear-resistant steel, with recommended materials being Q345B, Q390D, or equivalent or higher-grade low-alloy structural steel. The shell cutting edges (the blade portions in direct contact with the material) must be made of wear-resistant alloy steel (such as NM400 or NM500, hardness HB360–500) or fitted with a hard-faced wear layer. Worn cutting edges may be repaired by repair welding. Main structural components — the upper crossbeam, lower crossbeam, and struts must be made of Q345B or higher-grade steel. Welded joints must undergo non-destructive testing (100% UT inspection for critical butt welds). Pins and bushings — all moving hinge points (shell-to-lower-crossbeam connecting pins and strut end pins) must be made of 40Cr or 42CrMo steel with a quenched hardness of HRC40–50. Grease fittings must be provided between pins and bushings for lubrication. Wire rope pulleys — the wire rope pulleys on the grab's upper crossbeam must comply with GB/T 24809, with a sheave diameter to wire rope diameter ratio of D/d ≥ 20.
Grab Testing and Inspection
Test items specified in the standard: No-load test — all mechanisms must operate smoothly without jamming when the grab is in a free state; all shells must move in synchronization, and the clearance between shell cutting edges when closed must be uniform (maximum gap ≤3 mm). Load test — simulated grabbing tests using material at the rated capacity (no fewer than 10 cycles) to verify the grab's closing performance under full load and the sealing of the shells (no significant material leakage through shell gaps). Strength test — a static load test applying 1.25 times the rated load to the grab to check for permanent deformation or cracks in load-bearing components. Grabbing force test — measuring the actual grab volume under standard test material conditions, which must not be less than 90% of the rated capacity. Inspection rules — each grab must undergo a no-load test and visual inspection before delivery, with 20% of each batch randomly sampled for load testing (if any unit fails, all units in the batch must be tested individually). A type test is required every five years.
Grab Maintenance and Care
Routine maintenance of the grab directly affects its service life and operational safety. The standard sets out systematic maintenance requirements: Daily — perform a full visual inspection before each work shift, focusing on cutting edge wear, hinge point lubrication, and wire rope wear. Weekly — clean accumulated dust and material residue from all moving parts, and check pin-to-bushing clearance (replace bushings when single-side clearance exceeds 3 mm). Quarterly — conduct a comprehensive grab inspection, disassembling each hinge point to check pin wear (replace pins when diameter wear exceeds 3% of the original dimension) and performing visual and Magnetic Particle Inspection (MPI) on all weld seams. The standard also requires grab manufacturers to supply an operation and maintenance manual covering the lubrication chart, wear parts list, and disassembly/assembly procedures.
| Type | drive mode | Grab Ratio | Applicable Materials | Cost |
|---|---|---|---|---|
| Double Rope Grab (grab bucket) | Wire Ropeopen close+Hoisting / Lifting | 1.5~2.5 | Bulk Material(Coal, Sand & Grain) | Low |
| Single Rope Grab (grab bucket) | Single Rope+Locking Mechanism | 1.2~1.8 | Light Bulk Material | Low |
| Hydraulic Grab | Hydraulic Cylinder Drive | 2.5~4.0 | Lump Ore & Scrap Steel | High |
| Electric Grab (grab bucket) | Built-in Electric Hoist Winch | 1.8~3.0 | Various Materials | Medium |
FAQ
Q: What are the main grab bucket structural types and what materials are they suited for?
A: The standard classifies grab buckets by structural type as follows: 1) Double-jaw grab — consisting of two jaw plates, it offers a simple design and broad versatility, making it suitable for coal, ore, sand, and other bulk cargo; 2) Multi-jaw grab (orange-peel grab) — comprising 6–8 jaw plates, it delivers high digging force and a superior fill ratio, ideal for large lump ore and scrap steel; 3) Clamshell-type grab — the jaws close in a scissor-like motion, suited for fine-grained materials and hold cleaning operations. Additionally, by drive mode, grabs are classified into wire rope grabs (controlled by dual drums for hoisting and closing) and hydraulic grabs (jaw open/close actuated by the hydraulic system).
Q: What are the fill ratio (fill factor) requirements for grab buckets?
A: The fill ratio (or fill factor) is a key indicator of grab bucket loading efficiency — defined as the ratio of material weight picked up in one cycle to the grab's dead weight. The standard requires a fill ratio of ≥1.5 for double-jaw grabs (i.e., the material weight picked up must be at least 1.5 times the grab's dead weight) and ≥1.2 for multi-jaw grabs. A grab with an excessively low fill ratio suffers from poor operational efficiency and higher operating costs. Factors affecting the fill ratio include jaw plate shape and lip angle, material density and particle size, and the grab's lowering speed. Kelude Heavy Industry performs fill ratio verification tests on all grabs before delivery.
Q: What are the wear-resistant treatment requirements for grab bucket lip edges?
A: The lip edge is the part of the grab that comes into direct contact with the material and therefore experiences severe wear. The standard requires that lip edges be made of wear-resistant material or undergo wear-resistant treatment: 1) Hardfacing overlay — a high-chromium cast iron or chromium carbide wear layer is deposited on the lip surface, with a minimum overlay thickness of 5 mm and a hardness of HRC55–62; 2) Bolt-on replaceable wear plates — wear-resistant alloy steel plates (e.g., NM400, NM500) are fabricated as replaceable lip plates and secured to the jaw lip with bolts. Although replaceable wear plates carry a higher initial cost, they offer easier replacement and maintenance, resulting in a lower total lifecycle cost.
Q: What are the key points for daily inspection and maintenance of grab buckets?
A: Daily inspection: check that the jaw plates open and close smoothly, inspect the lip edges for significant wear or chipping, and examine the wire rope for broken wires and wear. Weekly inspection: check the wear condition of hinge pins and bushings at all hinge points (replace pins when diameter wear exceeds 3%), and lubricate all hinge points and sheave bearings. Monthly inspection: inspect the overall structure for deformation and cracks (with special attention to the jaw hinge areas and the upper cross-beam connections), and check the remaining thickness of the lip edge wear layer (re-weld or replace the lip plates when worn down to 40% of the original thickness). A static load test and fill ratio test are performed every six months.
