OEM-engineered hammerhead jibs, flat-top booms, luffing systems, and rack-and-pinion builder hoists ready for international site mobilization.
YOM 2019-2023
YOM 2019-2023
YOM 2019-2023
YOM 2019-2023
YOM 2019-2023
YOM 2019-2022
YOM 2019-2023
YOM 2013-2014
The working arm, or jib of a tower crane, represents the primary structural member dictating operational reach, bending moment resilience, dynamic hook path stability, and load-chart economics across modern civil and industrial sites. In both cantilevered topkit configurations (supported by high-tensile tie-rods) and topless flat-top structures (governed by pure bending moment capacity), crane jibs undergo intense static axial compression and dynamic cyclic torsional stresses during trolley traversing and high-velocity slewing.
For engineering procurement managers, EPC contractors, and equipment leasing conglomerates, evaluating jib of tower crane manufacturers and factories transcends basic tip-load metrics. It requires forensic assessment of chord steel metallurgy (e.g., Q345B, Q460D high-strength seamless tubes), robotic welding seam penetration profiles, modular section interconnection pin-connection tolerances, and ultrasonic non-destructive testing (NDT) under EN 14439 and FEM 1.001 guidelines.
Every jib segment fabricated by Tier-1 OEM manufacturing clusters undergoes strict finite element analysis (FEA) modeling under dynamic cyclic loads to eradicate fatigue crack propagation along chord joints:
Data validated through multi-axis strain gauge stress analysis under simulated hurricane wind gusts up to 150 km/h in out-of-service weathervaning configurations.
From micro-alloyed seamless main chords to multi-coat anti-corrosion barrier systems, examine how certified factories build crane jibs that withstand decades of fatigue cycles.
Main chords are subjected to massive bending moments. Top-tier factories utilize manganese-silicon alloyed steel (Q345B/Q355B or fine-grained Q460D/E) with high Charpy V-notch impact absorption toughness at -20°C to -40°C. Diagonal and horizontal lattice webs are formed from precision cold-drawn structural steel tubing, maximizing buckling capacity under dead load while keeping deadweight low.
Manual welding produces micro-fissures and thermal stress risers. Modern OEM jib manufacturing uses twin-wire submerged arc welding (SAW) and robotic gas metal arc welding (GMAW) under 80% Ar / 20% CO2 shielding gas. Factory QA mandates 100% magnetic particle testing (MT) on web fillet welds and full radiographic (RT) or phased-array ultrasonic testing (PAUT) on chord butt splices.
Dimensional drift leads to jib sagging and accelerated pin wear. Leading crane factories mount entire welded jib sections on dedicated five-axis CNC gantry milling machines. Connection pin ears are bored simultaneously at both ends in a single fixturing setup, ensuring true axial alignment with pin-hole tolerance controlled under H7/g6, eliminating racking and joint looseness.
The lower chord double-functions as the structural spine and high-precision runway rail for the trolley mechanism. Heavy-duty I-beam lower chords or cold-rolled rail guides must have absolute straightness (<1/1000mm deviation) to eliminate trolley vibration, premature wheel flange wear, and jerky load oscillation during acceleration or deceleration phases.
Topkit hammerhead jibs deploy rigid tie-rods or multi-strand steel cables to suspend the jib from the tower head (cat-head), minimizing chord steel mass. Conversely, flat-top jibs feature cantilevered box-truss connections engineered for sites with overlapping radii or air-space ceiling restrictions, reducing assembly crane tonnage and eliminating tie-rod tension balancing.
Long sea transport and harsh site microclimates demand C4 to C5-M marine-grade surface protection. Manufacturing protocols include internal & external automatic shot blasting to ISO 8501-1 Sa 2.5 cleanliness, zinc-rich epoxy primer (80μm), intermediate epoxy micaceous iron oxide build (100μm), and two-component aliphatic polyurethane topcoats (60μm).
Different megaproject typologies dictate specific jib geometry, moment capacity, and erection dynamics. Discover how EPC contractors match engineering needs with factory output.
| Application Sector | Predominant Jib Configuration | Critical Engineering Focus | Load Moment Class | Procurement Priority |
|---|---|---|---|---|
| Precast Modular Construction | Flat-Top (Topless) 60m - 75m | Tip load stiffness & tight hook radius positioning | 200 – 400 t·m | Zero Jib Deflection |
| Urban High-Density High-Rises | Luffing Jib (Boom Angle 15°-85°) | Out-of-service weathervaning radius under 12m | 160 – 350 t·m | Airspace Clearance |
| Bridge Pylon & Infrastructure | Topkit Hammerhead with Heavy Tie-Bars | High lateral cross-wind stability up to 25 m/s | 250 – 630 t·m | Dynamic Rigidity |
| Thermal & Nuclear Power Plants | Heavy-Duty Modular Lattice Jibs 70m - 80m | Ultra-heavy mid-radius picking capacity (16t - 25t) | 500 – 1200 t·m | Certified NDT Dossier |
| Shipyard Fabrication & Drydocks | Traveling Portal Crane Jibs | Continuous cyclic fatigue resistance under FEM A6/A7 | 315 – 800 t·m | Corrosion Resistance |
Senior SEO Growth & Engineering Insight: When engineering teams issue RFPs for used or newly manufactured replacement jibs, the critical bottleneck is rarely the initial tip capacity rating. The actual failure mode during audits stems from mismatching tie-bar elongation elasticity coefficients or installing mismatched pin metallurgy (e.g., swapping 40Cr quenched pins with mild alloy pins). Verified OEM suppliers maintain strict traceability on all fastener kits and load-path pin journals.
Reviewing production philosophies, steel utilization, and modular adaptability among the world's most reputable lifting equipment manufacturing brands.
Pioneer of the legendary MC and MD topkit series, and MCT flat-top lines. Potain jibs excel in pin-joint tolerance, lightweight chord optimization, and standardized tie-bar kinematics, reducing auxiliary mobile crane size requirements during assembly.
One of the world's largest lifting equipment producers. Famous for the QTZ and T-series flat-top jibs. Engineered with high-strength cold-drawn circular tube profiles that minimize aerodynamic drag during gale-force storms while providing substantial tip picking power.
Renowned for structural durability across harsh climate conditions. XCMG's automated manufacturing facilities deploy deep structural shot-blasting, multi-stage baking lacquer lines, and automated robotic lattice welding, guaranteeing extended fatigue lifetimes.
Yongmao is globally praised for heavy-duty shipyards and dam-building jibs with moments surpassing 600 t·m, while SANY modernizes flat-top booms with digital strain-monitoring telematics and anti-collision sensor packages directly embedded in chord profiles.
Crossing international borders requires complete alignment with statutory lifting equipment standards and specialized maritime container packaging.
Mandatory for the European Economic Area. Governs crane stability calculations, out-of-service wind resistance formulas, limit switches, and acoustic power safety levels across all active jib elements.
Rigorous operational safety protocol governing structural load indicators, monthly qualified person inspections, visual weld crack logs, and ANSI/ASME B30.3 crane boom design compliance.
Governs the classification of crane mechanisms and structural load cycles (A3 through A8), dictating allowable working stresses, safety factors against yield, and cumulative fatigue lifetime models.
Lattice jib sections are designed modularly in 5m, 10m, and 12m increments to nest precisely within standard 40-foot High Cube containers or 40-foot Flat Racks, eliminating breakbulk shipping surcharges.
Representative engineering values illustrating chord dimensions, steel grades, section weights, and maximum allowable tip moments for Tier-1 models.
| Jib Model Class | Standard Reach | Tip Capacity | Main Chord Dimensions | Material Grade | Average Jib Weight | Pin Diameter |
|---|---|---|---|---|---|---|
| 6013 Class (QTZ100) | 60 Meters | 1.30 Tonnes | CHS Φ114 × 10 mm | Q345B High Tensile | 8,450 kg | Φ55 mm / 40Cr |
| 6515 Class (STT153) | 65 Meters | 1.50 Tonnes | SHS 120 × 120 × 12 mm | Q355B / Q460D | 10,200 kg | Φ65 mm / 40CrMo |
| 7020 Class (QTZ200) | 70 Meters | 2.00 Tonnes | CHS Φ140 × 12 mm | Q355D Seamless | 13,800 kg | Φ70 mm / 42CrMo |
| 7025 Class (QTZ250) | 70 Meters | 2.50 Tonnes | CHS Φ159 × 14 mm | Q460E Fine Grain | 15,900 kg | Φ80 mm / 42CrMo |
| 7527 Class (Heavy EPC) | 75 Meters | 2.70 Tonnes | Built-up Box Chord | Q460D / Welded Plate | 19,500 kg | Φ95 mm / Quenched |
Clear, engineering-backed answers addressing crane jib replacement, refurbishment verification, metallurgy, transport, and structural safety.
Explore verified tower crane packages, secondary booms, and passenger/goods hoists inspected at our 30+ acre facility in Huai'an, China.
YOM 2019-2023
YOM 2019-2023
YOM 2019-2023
YOM 2018
YOM 2019-2023
OEM Standard
OEM Standard
OEM Standard
Operated by Huaian Zhongqiang International Trade Co., Ltd. in Jiangsu, China, housing inspected inventory from XCMG, Zoomlion, Potain, SANY, Yongmao, and Dahan, ready for physical or live video inspection.
Every structural weld, pin journal, chord tube, and connection bolt is verified against original manufacturer dimensional drawings, with complete ultrasound records provided to client engineers.
In-house dismantling, component color coding, export container stuffing, and land-to-sea transport through Shanghai and Qingdao ports to over 50 global destination harbors.
