Crane Hook Block Specifications by Tonnage & Price
Key Points A crane hook block is the load-handling device at the end of the hoisting mechanism, consisting of the hook body, cross beam, pulley block, side plates, and anti-loosening nuts. ① By manufacturing process, hooks are classified as forged hooks (GB/T 10051.1) and laminated hooks (JB/T 4207); ② Common rated loads range from 1t to 100t, with 18 hook sizes from 006 to 250; ③ Forged hooks have a safety factor ≥5, and a single lamella fracture in a laminated hook does not compromise overall safety; ④ Kelude Heavy Industry hook blocks undergo a 1.25× static load test and a 1.1× dynamic load test before delivery, with 100% flaw detection coverage.
Hook Block Structure and Classification
A hook block comprises five components: the hook body, cross beam, pulley block, side plates, and anti-loosening nuts. By manufacturing process, hook blocks fall into two main categories: forged hooks and laminated hooks. Forged hooks are integrally forged from 20# high-quality carbon steel, offering high strength and a compact structure—making them the most widely used hook type today. Laminated hooks, by contrast, are assembled from multiple steel plates riveted together; a single lamella fracture does not affect overall safety, making them ideal for high-temperature environments such as steelmaking and foundry applications.
Hook Material and Heat Treatment Process
Hook material directly affects load-bearing capacity and service life. Forged hooks use 20# high-quality carbon steel (GB/T 699) with the following chemical composition (mass fraction): C 0.17–0.24%, Si 0.17–0.37%, Mn 0.35–0.65%, P≤0.035%, S≤0.035%. After hot forging, the 20# steel undergoes quenching and tempering (quenching + high-temperature tempering) to produce a tempered sorbite microstructure, giving the hook both high strength and good toughness. After quenching and tempering, the hook body hardness is HB 105–156, and the load-bearing surface at the hook mouth can be locally hardened to HRC 35–40 for improved wear resistance.
Laminated hooks are made from Q345B high-strength low-alloy structural steel plates (≈S355J2) in thicknesses of 6–20mm, with multiple plates joined by riveting or bolted connections. Q345B contains 1.0–1.6% Mn, has a yield strength ≥345MPa, and offers better low-temperature impact performance than 20# steel (KV₂≥34J at -20°C). Individual lamella plates in laminated hooks do not undergo heat treatment, but each plate is subject to visual inspection and ultrasonic thickness measurement before delivery to ensure freedom from lamination, laps, and other defects.
Kelude Heavy Industry forged hook blocks are manufactured to the GB/T 10051.1-2010 standard. Each batch of raw material is supplied with a Material Certificate (including chemical composition and mechanical properties test reports), and third-party material re-inspection is available upon request.
Hook blocks are available in 18 hook sizes—006, 01, 02, 03, 05, 08, 12, 16, 20, 25, 32, 40, 50, 63, 80, 100, 125, and 250—corresponding to rated loads from 1t to 100t. Kelude Heavy Industry hook blocks strictly implement the GB/T 10051.1 standard, and forged hooks are subject to Magnetic Particle Inspection (MPI) or Ultrasonic Testing (UT) to ensure freedom from cracks, folds, and other defects.
Forged vs. Laminated Hook: Specification Comparison
| Item | Forged Hook | Laminated Hook |
|---|---|---|
| execution standard | GB/T 10051.1 | JB/T 4207 |
| Material | 20#Steel Forging | Q345B (≈S355J2)Steel Plate Laminated Riveting |
| Safety factor | ≥5 | ≥5(Single Hook Fracture Safety) |
| Applicable Temperature | -20℃~+200℃ | -40℃~+400℃ |
| inspection requirements | Magnetic Particle/Ultrasonic Testing (UT) | Per Lamella Steel Plate Visual inspection |
| Primary Application | Standardcrane, Electric Hoist | Metallurgical, Casting, Heat treatment |
Hook Block Reference Price List by Capacity
| Hook Size | rated load(t) | Forged Hook Reference Price(CNY) | Laminated Hook Reference Price(CNY) |
|---|---|---|---|
| 006 | 1 | 180~260 | — |
| 02 | 2 | 250~380 | — |
| 05 | 5 | 450~680 | 720~960 |
| 12 | 10 | 850~1280 | 1200~1650 |
| 25 | 20 | 1650~2400 | 2200~3200 |
| 50 | 32 | 2800~4200 | 3600~5200 |
| 80 | 50 | 4500~6800 | 5800~8600 |
| 125 | 80 | 7800~12000 | 9800~15500 |
| 250 | 100 | 13500~21000 | 17500~28000 |
Note: The above prices are Kelude Heavy Industry's ex-factory reference prices for July 2026, including the pulley block and side plate assembly, excluding freight and installation. Final pricing depends on the specific hook size, pulley configuration, and order quantity.
Hook Block Selection Precautions
Key Points of the GB/T 10051 Standard Series
The GB/T 10051 "Lifting Hooks" standard series consists of five parts: Part 1 covers mechanical properties, lifting capacity, stress, and materials (GB/T 10051.1); Part 2 specifies technical requirements for forged hooks (GB/T 10051.2); Part 3 covers acceptance inspection of forged hooks (GB/T 10051.3); Part 4 specifies technical requirements for laminated hooks (GB/T 10051.4); and Part 5 defines discard criteria for hooks (GB/T 10051.5). Key provisions: forged hooks must be made of 20# steel or 20CrMo grades, with a forging ratio of at least 3. After quenching and tempering, the mechanical properties must achieve a tensile strength Rm ≥ 420MPa, yield strength ReL ≥ 350MPa, elongation after fracture A ≥ 20%, and impact absorption energy KV₂ ≥ 34J at -20°C. Stress at the critical section (inner side of the hook curve) is calculated based on the rated load, with a safety factor of at least 5.
Acceptance inspection includes visual inspection (unaided eye plus 5× magnifying glass to check for surface cracks, folds, overheating, and other defects), dimensional inspection (dimensional tolerances per GB/T 1804-m for the corresponding hook size), and Magnetic Particle Inspection (full surface, with sensitivity verified using A-type test piece 30/100). One sample from each batch of forged hooks must also undergo a destructive tensile test to fracture, with the fracture load ≥ rated load × 5. Every Kelude Heavy Industry hook undergoes full inspection per the above standards before delivery, accompanied by material certificates and NDT reports.
Hook Flaw Detection Methods and Inspection Intervals
Magnetic Particle Inspection (MPI) is the most commonly used method for detecting surface and near-surface flaws in forged hooks, including cracks, hairline cracks, and folds. The inspection process involves cleaning the hook surface, applying magnetic suspension, magnetizing with AC or DC current, and observing under UV light. Sensitivity requirement: the A-type test piece 30/100 must be clearly visible in any orientation. Ultrasonic Testing (UT) is used to detect internal defects such as inclusions, flakes, and cracks, using a longitudinal wave straight probe scanning from the hook body end face. Testing is performed in accordance with JB/T 5000.15-2007.
Inspection intervals: ① Hooks in normal service require MPI every six months; ② Hooks in high-temperature environments (metallurgical/foundry) require inspection quarterly; ③ Newly purchased hooks must be inspected before first use; ④ Hooks must be inspected immediately after an overload or impact incident. Kelude Heavy Industry offers hook inspection services — customers can ship hooks back to us or schedule on-site testing.
Hook Discard Criteria and Practical Examples
GB/T 10051.5 specifies the following discard criteria:
① Throat opening increased by more than 15% from the original dimension;
② Hook body twisted more than 10°;
③ Wear at the critical section (inner side of the hook bend) reaching 10% of the original dimension;
④ Cracks found at any point on the surface;
⑤ Thread corrosion or stripped threads on the hook shank;
⑥ Visible plastic deformation of the hook (bending or twisting).
Example 1: A 20t forged hook (hook size 25) was measured after 3 years of service. The throat opening had increased from the original 72mm to 85mm (an 18% increase), exceeding the 15% discard threshold. The hook was condemned and replaced.
Example 2: A laminated hook at a steel mill had been in service for 5 years. Disassembly inspection revealed a 5mm-wide transverse crack on the innermost steel plate. Because laminated hooks transfer load through riveted plate connections, a crack in a single plate does not immediately cause overall fracture, but the crack will propagate progressively. Per GB/T 10051.5, a crack in any single plate requires scrapping the entire hook assembly.
Example 3: A forged hook in a foundry workshop was found to have twisted approximately 12° from its original 0° position. The twisting resulted from torsional loads caused by load sway during lifting. Per the standard, a twist angle of 10° or more requires immediate replacement.
Hook Installation and Daily Inspection Essentials
Installation: When connecting the hook to the pulley block cross beam, the anti-loosening nut must be torqued to the specified value and secured with a cotter pin. The hook latch (anti-detachment device) should spring back freely, and the closed gap must be less than 5% of the hook opening size. The hook should pivot freely ±90° or more on the cross beam without binding. Kelude Heavy Industry hook blocks are fully assembled and functionally tested before delivery.
Daily Inspection Checklist (operator routine inspection):
① Visually inspect the hook surface for cracks, nicks, or significant wear;
② Verify the hook latch springs back into position correctly;
③ Check the anti-loosening nut for any signs of loosening;
④ Sound test: tap the hook body lightly with a tool — a clear ringing sound indicates no cracks, while a dull thud may suggest internal defects (requiring further flaw detection to confirm).
Monthly Maintenance: Apply grease to the hook threads for corrosion protection; measure the throat opening and compare against the original value, recording the wear amount.
Frequently Asked Questions
Q: Can the hook be replaced individually on a hook block?
A: Yes. The forged hook body can be replaced individually while retaining the cross beam, pulley block, and side plates. However, Kelude Heavy Industry recommends replacing the entire hook block after more than 5 years of cumulative service or after two hook replacements, as the side plates and cross beam also experience fatigue damage.
Q: How do I know when a hook needs to be scrapped?
A: GB/T 10051.5 specifies the following discard criteria: ① Throat opening increased by more than 15% from the original dimension; ② Hook body twisted more than 10°; ③ Surface cracks or fatigue fracture; ④ Wear at the critical section reaching 10% of the original dimension; ⑤ Thread corrosion or stripped threads. Kelude Heavy Industry offers free hook inspection services — customers can ship used hooks back for evaluation.
Q: What are the advantages of a laminated hook over a forged hook?
A: The key advantage of a laminated hook is "fracture safety" — multiple steel plates are riveted together, so a crack in one plate will not cause the entire load to drop. Laminated hooks are also high-temperature resistant (up to 400°C) and allow internal damage to be detected through sound testing. The downsides are larger dimensions, higher dead weight, and a cost approximately 1.3 to 1.5 times that of a forged hook.
Q: What is the warranty period for Kelude Heavy Industry hook blocks?
A: Kelude Heavy Industry hook blocks carry an 18-month warranty from the date of factory shipment. Any non-user-induced quality defects such as cracks, fractures, or weld separation within the warranty period are covered by free replacement. Each hook comes with a material certificate and NDT report, and free selection technical support is available.
This guide provides a comprehensive overview of crane hook block specifications and pricing across load capacities. Kelude Heavy Industry offers the full range of forged hooks and laminated hooks, with custom non-standard sizes available upon request with drawings. For selection assistance or a quotation, contact the Kelude Heavy Industry technical team for a one-on-one consultation.
Kelude Heavy Industry supplies the complete range of forged and laminated hooks, supporting custom non-standard dimensions from customer drawings. Every hook ships with a GB/T 10051 material certificate and Magnetic Particle Inspection (MPI) report, backed by an 18-month warranty. For selection guidance or a quotation, contact the Kelude Heavy Industry technical team for a tailored solution.
