Предыстория проекта
This project is located at a large machinery manufacturing park in Hai Phong, Vietnam. The plant primarily handles welding, sandblasting, and assembly of heavy steel structures. Located near the bay, the environment features high humidity and high salinity. Equipment faces extreme corrosion risks. Since the production line frequently handles 20-ton steel components, existing single-girder cranes failed to meet strength and anti-corrosion requirements. The client required a high-rigidity double-girder gantry crane with superior environmental adaptability.
Gantry Crane Technical Specifications
The core technical indicators for the gantry crane selected for this case are as follows:
| Parameter Item | Технические характеристики |
| Номинальная грузоподъемность | 20 Ton |
| Основная балочная конструкция | Double Box Girder |
| Crane Travel Speed | 5 m/min |
| Lifting Power Source | Electric Drive |
| Anti-corrosion Grade | C5-M (Marine Atmospheric Standard) |
| Метод контроля | VFD (Variable Frequency Drive) Control |
| Рабочий класс | А5 |
20-Ton Gantry Crane Core Implementation Plan
Double Box Girder Structural Design
For the 20-ton lifting load, a double box girder structure ensures structural rigidity under full load. Main girders use Q345B steel. They are welded via automatic submerged arc welding to eliminate residual stress. The camber is pre-set at 1.2‰ of the span. This ensures the beam remains level during full-load lifting and prevents load swaying.
Anti-Corrosion Treatment System
For the coastal salt-spray environment in Vietnam, this crane uses a strict treatment process. This ensures a service life exceeding 15 years:
- Surface Cleaning: All structural parts undergo sandblasting to Sa 2.5 standards. This removes all oxide scale and rust.
- Primer System: High-performance epoxy zinc-rich primer is applied (Dry Film Thickness ≥ 80μm). This provides cathodic protection.
- Intermediate and Topcoat: Epoxy micaceous iron intermediate paint is applied. The topcoat uses polyurethane resin for excellent UV and salt-spray resistance. Total dry film thickness exceeds 240μm.
- Critical Component Protection: Motor covers, gearboxes, and control cabinets are sealed to IP55 standards. This prevents salt mist from entering the electrical systems.
Crane Travel and Drive Control
The 5 m/min speed setting ensures precision during heavy load handling. The system includes three-in-one geared motors with electromagnetic brakes.
- VFD Speed Regulation: Vector-controlled inverters provide smooth control during starting, acceleration, and stopping. This reduces inertial swaying and protects the load.
- Power Input: A cable reel system ensures stable power transmission during long-distance travel. This avoids downtime risks caused by poor contact in sliding lines.
Installation and Commissioning
The gantry crane was assembled on-site in Vietnam. Key challenges included beam positioning and leg verticality control. The team used total stations for multi-point calibration. This ensured the span deviation stayed within ±2mm.
During the load testing phase, a 25-ton weight (125% load) was used for static tests. This checked the main girder deflection. A 22-ton weight (110% load) was used for dynamic tests. This verified braking distances and VFD operation curves at 5 m/min. Results showed all performance metrics meet industrial standards.
Project Results and Benefits
This 20-ton gantry crane significantly improved workshop logistics efficiency after commissioning.
- Efficiency Increase: The VFD system improved positioning accuracy. Single lifting operation time was reduced by approximately 20%.
- Lower Maintenance Costs: The high-grade coating showed no corrosion after 12 months. This greatly reduced equipment maintenance frequency.
- Safety Assurance: Multiple limit switches and overload protection ensure safety during 24-hour operations. This eliminated major safety hazards.
Through this project, the HSCRANE team solved core lifting needs. We built a durable logistics infrastructure for a high-corrosion environment. This proves the importance of customized design for specific climates.
