Double Girder Overhead Crane For Metallurgical Industry

Key Features of Double Girder Overhead Crane for Metallurgical Industry

Heavy-Duty Double Girder Design – Provides high strength, stability, and capacity up to 550 tons.

High Temperature Resistance – Equipped with heat-insulated hooks, motors, cables, and electrical parts for safe operation near molten metal.

Special Ladle Hook – Double safety brakes and insulation ensure secure handling of hot metal ladles.

Continuous Operation Capability – Designed for duty class A6–A8 (FEM/DIN), suitable for 24/7 heavy metallurgical processes.

Advanced Control System – Smooth lifting and traveling via Variable Frequency Drive (VFD) or PLC automation.

Safety Protections – Includes overload limiter, dual braking system, limit switches, sound & light alarms, and emergency stop.

Operator-Friendly Cabin – Heatproof glass, ergonomic controls, and optional air-conditioning for safe operation in harsh environments.

Customizable Span & Capacity – Tailored to workshop dimensions and production needs.

Precision & Reliability – Ensures accurate ladle pouring and material handling in steel mills and foundries.

Compliance with Standards – Manufactured according to FEM, DIN, ISO, CMAA, and metallurgical safety codes.

Comparison

Core Components：Bearing, Gearbox, Motor, Pump

Place of Origin：Henan, China

Warranty：1 Year

Weight (KG)：2000 kg

Video outgoing-inspection：Provided

Machinery Test Report：Provided

Design：Double beam

Effectiveness：high efficiency

Operating speed：High speed operation

Stability：Anti-swing function

Color：Optional

Power Source：110V/220V/230V/380V/440V,customized

Span：7.5-31.5m

Key Components of a Metallurgical Double Girder Overhead Crane

1. Bridge Structure

Main Girders: Fabricated from high-strength, low-alloy steel (e.g., S355JR/J2, Q345B). Often use a box-girder design for superior rigidity and resistance to torsional stresses under heavy, off-center loads. They are often coated with heat-resistant paint.

End Trucks (End Carriages): House the wheels, bearings, and drive mechanisms for the crane's longitudinal movement. Feature heavy-duty forged steel wheels and anti-derailment guards to ensure safety on the runway rails.

2. Hoisting Unit (The Core Lifter)

This is highly specialized for metallurgy.

Hoist Motor: Class H (180°C) insulation or higher is standard. Often totally enclosed fan cooled (TEFC) or even explosion-proof for environments with combustible dust.

Wire Rope & Drum: Uses high-grade, heat-resistant wire rope (e.g., with a steel core). The drum is machined for precise rope spooling.

Hook Block: For the most severe applications (ladle handling), a redundant pulley system is used. The hook itself is forged from alloy steel and may be of a C-hook design for coils or a special ladle hook.

Braking System: Multiple redundant brakes:

Primary holding brake.

Emergency mechanical brake.

Regenerative braking via the Variable Frequency Drive (VFD).

3. Trolley Frame

The structure that carries the hoisting unit across the bridge girders.

Drive Mechanism: Equipped with dual drives (one motor on each side) for synchronized movement and to prevent trolley skewing.

Buffers: Heavy-duty shock-absorbing buffers at each end.

4. Motion Drive Systems

Travel Drives (Bridge & Trolley): Utilize 3-phase AC motors controlled by Variable Frequency Drives (VFDs). VFDs provide smooth, controlled acceleration and deceleration, crucial for preventing load swing, especially with molten metal.

Gearboxes: Hardened helical gear reducers for high torque, efficiency, and durability under constant heavy loads.

5. Electrical and Control System

Power Supply: Insulated Conductor Bar System (ICBS) is preferred over festoon systems in dusty metallurgical plants as it is enclosed and more reliable.

Control Cabinets: IP54 or IP55 rated for protection against dust and water ingress. Components are selected for high thermal tolerance.

Operator Interface:

Pendant Station: Heavy-duty, heat-resistant pendant with emergency stop.

Radio Remote Control: Essential for operator safety, allowing control from a safe distance when handling ladles or near furnaces.

Pulpit Cabin: An air-conditioned cabin attached to the crane for full-time operators, providing a protected environment with a full view of the shop floor.

6. Safety and Protection Systems (CRITICAL)

Overload Limit Device: Mandatory. Prevents the crane from lifting a load beyond its rated capacity.

Double-Limit Switches: For hoisting and lowering to prevent over-travel and "two-blocking."

Anti-Collision System: Uses laser or radar to prevent cranes on the same runway from colliding.

Anemometer: For outdoor cranes, measures wind speed and can trigger an alarm or disable crane functions if limits are exceeded.

Ladle Monitoring System (for Ladle Cranes): Monitors ladle weight and hook engagement integrity. The most critical safety system for preventing molten metal spills.

Heat Shields: Protective plates placed between the hoist mechanism and the heat source (e.g., the ladle) to deflect radiant heat.

Emergency Stop Systems: Located at multiple points (pendant, radio, pulpit).

7. Specialized Attachments (Auxiliary Lifting Devices)

C-Hooks: For handling steel coils.

Electromagnets: For moving scrap steel, plates, or sheets. Require a separate generator on the crane.

Motorized Grab Buckets: For handling bulk materials like scrap or coal.

Ladle Lifting Beams: Specially engineered frames with hooks designed to safely engage the trunnions of a molten metal ladle.

Sketch

Main technical

Advantages of Double Girder Overhead Cranes in Metallurgy

Double girder cranes are the backbone of metallurgical facilities due to their unparalleled ability to handle the industry's extreme demands.

1. Exceptional Strength & High Load Capacity

Heavy-Duty Performance: Designed to handle the most massive loads, from 50 tons to well over 500 tons. This is essential for ladles of molten metal, large coils, and massive slabs.

Robust Construction: The double girder design provides superior structural integrity and rigidity, resisting the twisting and bending forces caused by off-center and dynamic loads.

2. Enhanced Safety for Extreme Environments (Most Critical Advantage)

Built for Heat: Components are specified with high-temperature ratings (e.g., Class H insulation motors, heat-resistant paints, and seals) to operate reliably near furnaces and molten material.

Redundant Safety Systems: Feature multiple fail-safes like dual brakes (primary and emergency), overload limiters, and ladle monitoring systems to prevent catastrophic accidents involving molten metal.

Operator Protection: Radio remote control is standard, allowing operators to control the crane from a safe distance, away from heat, fumes, and potential spill hazards.

3. Superior Precision and Control

Smooth Operation: Equipped with Variable Frequency Drives (VFDs) on all motions (hoist, trolley, bridge). This allows for incredibly smooth acceleration and deceleration, enabling precise positioning of valuable and dangerous loads.

Anti-Sway Technology: Advanced control systems automatically minimize load swing, which is critical when maneuvering a ladle of molten metal through a crowded shop floor without splashing.

4. Durability and Low Lifecycle Cost

Premium Components: Built with industrial-grade gears, hardened wheels, and heavy-duty drives that withstand continuous, high-cycle duty (FEM M7/M8 class).

Reduced Downtime: Their robust design and use of premium materials lead to longer service intervals, fewer breakdowns, and higher overall availability, which is vital for 24/7 metallurgical production.

5. Design Flexibility and Customization

Specialized Attachments: Can be seamlessly integrated with C-hooks for coils, electromagnets for scrap, and custom ladle lifting beams.

High Lifting Height: The design allows for greater hook height compared to single girder cranes, providing the necessary clearance for large ladles and stacked material.

Applications in the Metallurgical Industry

The double girder crane is indispensable across the entire metal production chain:

The manufacturing process of a QDY metallurgical casting bridge crane involves strict quality control and specialized engineering to ensure durability, heat resistance, and safety. Below is a step-by-step breakdown of the production procedure:

1. Design & Engineering

Load & Environment Analysis – Calculations for lifting capacity (5–500+ tons), span, and heat resistance.

CAD/3D Modeling – Structural design, stress simulations (FEA), and compliance with ISO, FEM, or GB standards.

Customization – Optional features (explosion-proofing, insulated hoists, automation) are integrated.

2. Material Selection & Preparation

Main Girders & End Carriages – High-strength steel (Q345B, Q460C) or heat-resistant alloy steel.

Wire Ropes & Hooks – Special heat-treated alloy steel (for molten metal handling).

Electrical Components – High-temperature-resistant cables, motors, and insulation materials.

3. Fabrication of Key Components

A. Bridge Girder Construction

Cutting & Welding – CNC plasma/laser cutting for precision; submerged arc welding (SAW) for high-strength joints.

Heat Treatment – Stress-relieving annealing to prevent deformation.

Machining – Drilling, milling, and surface grinding for assembly accuracy.

B. Hoist & Trolley Assembly

Hoist Drum & Gearbox – Machined for smooth operation; tested under 1.25x rated load.

Heat-Resistant Brakes – Dual-disc or electromagnetic brakes for fail-safe holding.

Ladle Hook & Safety Latch – Forged and ultrasonically tested for cracks.

C. End Trucks & Runway System

Wheel & Rail Machining – Hardened steel wheels for long wear life.

Drive Motors & Reducers – Equipped with anti-skid mechanisms for heavy loads.

4. Electrical & Control System Integration

Festoon/Conductor Bar System – For power supply along the runway.

Variable Frequency Drives (VFDs) – For smooth speed control and energy efficiency.

Safety Circuits – Overload sensors, limit switches, and emergency stop.

Operator Controls – Pendant, cabin, or remote/automated systems.

5. Surface Treatment & Corrosion Protection

Sandblasting (SA 2.5 Grade) – Removes rust and improves paint adhesion.

High-Temp Paint/Coating – Zinc-rich primer + heat-resistant topcoat (up to 800°C).

Critical Component Insulation – Ceramic fiber or refractory coatings on hooks and ropes.

6. Assembly & Testing

A. Pre-Assembly Checks

Dimensional inspection of girders, trolley, and end carriages.

Alignment of runway rails and crane tracks.

B. Load Testing (Per ISO 4310 / GB Standards)

No-Load Test – Checks motor, brake, and travel functions.

Static Load Test – 1.25x rated capacity for 10+ minutes.

Dynamic Load Test – 1.1x rated capacity with repeated movements.

Emergency Brake Test – Verifies fail-safe mechanisms.

C. Heat Resistance Validation (For Foundry Cranes)

Simulated high-temperature exposure (if required).

7. Packaging & Delivery

Disassembly (if needed) – For large cranes, components are shipped separately.

Anti-Corrosion Packaging – VCI film or desiccant for overseas transport.

Documentation – Manuals, test reports, and certifications (CE, ISO, GOST, etc.).

8. Installation & Commissioning (On-Site)

Runway alignment and crane reassembly.

Final load testing and operator training.

Workshop view:

The company has installed an intelligent equipment management platform, and has installed 310 sets (sets) of handling and welding robots. After the completion of the plan, there will be more than 500 sets (sets), and the equipment networking rate will reach 95%. 32 welding lines have been put into use, 50 are planned to be installed, and the automation rate of the entire product line has reached 85%.