QL Type Double Girder Hang Beam Overhead Crane

What is a QL Type Crane?

The QL Type Double Girder Hang Beam Overhead Crane is a standardized, modular overhead crane design primarily manufactured in China, following specific design codes (often referenced as "Q" for bridge crane and "L" for overhead type). It represents an economical, reliable double girder solution for medium-duty industrial applications.

Key Identifier: "QL" typically denotes a Chinese standard double girder overhead traveling crane with specific design parameters, distinct from European (FEM) or American (CMAA) standards.

 

ADVANTAGES OF QL TYPE DESIGN

1. Economic Benefits

Standardized Production: Mass-produced components reduce cost

Modular Design: Easy to assemble, disassemble, and modify

Competitive Pricing: Typically 20-40% less than European equivalents

Easy Maintenance: Standard components with wide spare parts availability

2. Performance Features

Adequate Strength: Suitable for most industrial workshops

Reliable Operation: Proven design with decades of application history

Simple Control: Straightforward operation suitable for general workers

Good Span Coverage: Can cover most standard factory bays

3. Practical Advantages

Quick Delivery: Standard configurations available from stock

Easy Installation: Pre-drilled, pre-fabricated components

Local Support: Widely available service in industrial regions

Documentation: Standard manuals in multiple languages

 

QL vs. EUROPEAN (FEM) STANDARD

Aspect	QL Type Crane	European FEM Crane
Design Standards	Chinese JB/T standard	FEM 1.001/ISO 8686
Safety Factors	Generally adequate	Higher margins
Component Quality	Standard industrial grade	Premium/high-grade
Control Sophistication	Basic to medium	Advanced, often with VFD
Price	Lower (20-40% less)	Higher
Delivery Time	Shorter (8-12 weeks)	Longer (16-24 weeks)
After-Sales Support	Variable by supplier	Generally comprehensive

 

TECHNICAL SPECIFICATIONS EXAMPLE

Model: QL-20t/22.5m A4

Capacity: 20 metric tons

Span: 22.5 meters

Lifting Height: 12 meters

Hoist Speed: 3.5 m/min (main), 7.0 m/min (auxiliary if equipped)

Crane Travel Speed: 30 m/min

Trolley Travel Speed: 20 m/min

Work Duty: A4 (medium duty, ~150 starts/hour)

Control: Pendant push-button, 8-button controller

Motor Power: Hoist 30kW, Crane travel 2x5.5kW, Trolley 2.2kW

Power Supply: 380V, 3-phase, 50Hz

Ambient Temperature: -20°C to +40°C

Relative Humidity: ≤85%

1. Bridge Structure (Double Girder System)

Main Girders

Welded box-type steel structure

High rigidity and load-bearing capacity

Designed for heavy-duty and metallurgical service

Maintenance Platforms

Walkways, handrails, and guardrails

Easy access for inspection and maintenance

2. End Beams

Welded steel end carriages

CNC-machined wheel seats

High-strength connection to main girders

Equipped with buffers and limit devices

3. Crane Traveling Mechanism

Crane traveling motors

Gear reducers

Electromagnetic or hydraulic brakes

Wheel sets (for bridge movement)

4. Trolley (Winch Trolley System)

Heavy-duty trolley frame

Lifting motor(s)

Gearbox and transmission system

Wire rope drum with rope guide

5. Lifting Mechanism

High-strength wire ropes

Pulley blocks and sheaves

Multiple lifting points for synchronous lifting

Designed for smooth and stable operation

6. Hang Beam (Lifting Beam) Device

Box-type or truss-type hang beam

Customized beam length and structure

Equipped with:

Hooks

Clamps

Slings

Load balancing and anti-tilt design

 

7. Electrical System

Main electrical control cabinet

Frequency inverter (VFD) for speed regulation

Power supply system (busbar or cable)

Heat-resistant electrical components

 

8. Control System

Operator cabin with wide field of vision

Pendant control

Wireless remote control (optional)

PLC-based synchronous lifting control (optional)

 

9. Safety Protection Devices

Overload protection limiter

Upper and lower lifting limit switches

Travel limit switches

Emergency stop system

Dual braking system

10. Auxiliary Components

Buffers and rail sweeps

Cable festoon or drag chain system

Grounding and lightning protection

Warning lights and alarms

Sketch

Main technical

 

 

1. Ideal for Long and Heavy Materials

Hang beam design provides uniform load distribution

Prevents bending, deformation, or slipping of long workpieces

Especially suitable for steel plates, slabs, billets, pipes, and profiles

2. High Load Capacity & Stability

Double girder box structure ensures excellent rigidity

Supports large lifting capacities and wide spans

Stable operation even under heavy-duty and continuous use

3. Synchronous Multi-Point Lifting

Multiple lifting points on the hang beam

Ensures balanced lifting and accurate positioning

Reduces torsion stress on materials and crane structure

4. Designed for Metallurgical Duty

Suitable for A6–A8 working class

Heat-resistant motors, cables, and electrical components

Reliable performance in high-temperature and harsh environments

5. Enhanced Safety Performance

Overload protection system

Dual braking mechanisms

Limit switches and emergency stop devices

Minimizes risk during heavy and long-material lifting

6. Smooth & Precise Operation

Frequency inverter (VFD) control for lifting and traveling

Low impact, reduced vibration, and precise positioning

Improves handling efficiency and protects materials

7. Flexible Control Options

Operator cabin with wide visibility

Pendant control

Wireless remote control (optional)

8. Long Service Life & Low Maintenance

High-quality steel structure and components

Optimized design reduces wear and fatigue

Low operating and maintenance costs

 

1. Steel Mills & Metallurgical Plants

Handling steel slabs, billets, and plates

Feeding rolling mills and heat treatment lines

2. Plate & Profile Production Workshops

Transporting long steel plates and profiles

Loading and unloading production lines

3. Pipe & Tube Manufacturing Plants

Lifting and positioning large-diameter pipes

Safe handling of long tubular materials

4. Heavy Manufacturing & Fabrication

Large steel structure workshops

Heavy equipment assembly areas

5. Shipyards & Offshore Fabrication

Handling long steel sections and components

Pre-assembly and fabrication zones

6. Storage & Logistics Yards

Stacking and transferring long materials

Improving material handling efficiency

 

The QL Type Double Girder Hang Beam Overhead Crane is a heavy-duty metallurgical crane designed for lifting long, heavy, and high-temperature materials. Its production follows strict quality control standards to ensure high strength, precision, and safety.

1. Project Requirement Confirmation & Engineering Design

Confirm lifting capacity, span, lifting height, and hang beam length

Working class confirmation (A6–A8)

Structural strength and fatigue calculations

Synchronous multi-point lifting design

Electrical and safety system configuration

2. Raw Material Selection & Inspection

High-strength steel plates (Q345B / Q355 / Q460)

Steel certificate verification

Ultrasonic testing (UT) for main load-bearing plates

Pre-treatment cleaning

3. CNC Cutting & Component Preparation

CNC plasma or flame cutting of:

Main girder plates

End beams

Hang beam components

Bevel cutting for full-penetration welding

Dimensional inspection and marking

4. Double Girder Fabrication

Box-type girder assembly using precision jigs

Submerged arc welding for primary welds

CO₂ gas-shielded welding for secondary structures

Stress relief treatment

Camber and straightness correction

Weld inspection (UT / MT)

5. End Beam & Crane Traveling Mechanism Manufacturing

End beam welding and machining

CNC machining of wheel seats

Installation of wheels, motors, reducers, and brakes

Running alignment inspection

6. Trolley & Lifting Mechanism Assembly

Heavy-duty winch trolley assembly

Installation of lifting motors, gearboxes, and wire rope drums

Assembly of pulley blocks and hook groups

Multi-point lifting system setup

7. Hang Beam (Lifting Beam) Fabrication

Fabrication of box-type or truss-type hang beam

Installation of hooks, clamps, or slings

Load balancing and synchronization adjustment

Trial fitting and inspection

8. Electrical & Control System Installation

Installation of main electrical cabinet

Frequency inverter (VFD) system

PLC-based synchronous lifting control (optional)

Wiring for high-temperature environments

9. Safety Protection System Installation

Overload limiters

Upper and lower lifting limit switches

Travel limit switches

Emergency stop devices

Dual braking system

10. Surface Treatment & Painting

Shot blasting to Sa2.5 standard

Anti-corrosion primer coating

Epoxy intermediate layer

Heat-resistant polyurethane topcoat

11. Factory Assembly & Testing

Partial or full factory assembly

No-load functional testing

Static load test (125% rated load)

Dynamic load test (110% rated load)

Synchronous lifting accuracy test

12. Packing, Delivery & On-Site Commissioning

Modular disassembly for transportation

Moisture-proof packaging for electrical parts

On-site installation and alignment

Final commissioning and acceptance testing

Operator training and documentation handover

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%.