How to install QU120 crane rail correctly?
The core of correct installation lies in strict control of rail alignment accuracy, matching of fastening systems, reliable joint connection and standardized welding process, so as to ensure uniform stress transmission under extreme wheel pressure and reduce later maintenance costs.
For coastal or corrosive environments, surface protection treatment can be added to the rail and fasteners in advance.
Step 1: Base leveling and rail laying positioning
The foundation of QU120 crane rail installation is a flat and high-strength bearing foundation, which can be a concrete foundation, steel crane beam or steel structure platform. Before laying the rail, clean up sundries on the foundation surface, check the flatness of the foundation, and mark the rail center line and bolt hole positions according to the design drawing.
When laying the rail, hoist it gently to avoid collision and deformation of the rail end. Place the rubber pad under the rail bottom first to ensure the pad is aligned with the rail bottom center and does not deviate. For curved sections, pre-bent curved rails can be used to avoid forced bending during installation that causes internal stress.
Step 2: Control alignment and gauge tolerance
The elevation deviation of the rail top shall be adjusted according to the design requirements, and the height difference between the two rails shall be kept within the allowable range to avoid partial load of the crane wheels.
When adjusting the position, use a special rail aligner and a level gauge for measurement, and fix it temporarily after adjustment to prevent displacement during subsequent fastening.
Step 3: Install fastening system and fix rail
After the rail position is adjusted, install the rail pressing device in sequence. When tightening, follow the principle of diagonal and step-by-step tightening to avoid local stress concentration, and the contact surface shall not be skewed. The tightening torque of 10.9 grade high-strength bolts shall be calibrated according to ISO 16047 torque-tension standard to ensure consistent pre-tightening force of all fasteners. After installation, check one by one to confirm that there is no looseness or missing installation.
There are two main connection methods for QU120 rail joints: bolted joint with fishplate and aluminothermic welded joint, which are selected according to the working condition load and operation requirements.
For bolted joints, and tighten 10.9 grade high-strength bolts symmetrically to ensure close fit between the joint end faces and reduce the gap. For heavy-du1ty crane tracks with high frequency of use and large impact load, aluminothermic welding is preferred: the aluminothermic reaction temperature exceeds 2500°C, the weld strength reaches more than 95% of the base metal tensile strength, no external power supply is needed, and the joint is smooth and impact-resistant after welding.
Step 4: Welding process specifications (if welding is required)
When welding QU120 crane rail, DC reverse polarity welding is recommended. When the ambient temperature is lower than 10°C, preheat the rail end before welding, and strictly control the interlayer temperature and welding speed to ensure weld quality and avoid cold cracks.
After welding, clean the weld surface, grind the rail top and rail side to be flush with the base metal, and check the weld for defects such as pores, cracks and incomplete penetration. For important working conditions, non-destructive testing shall be carried out on the weld to confirm that the internal quality meets the standard requirements.
Step 5: Post-installation inspection and acceptance
After all installation work is completed, conduct a comprehensive inspection: recheck the gauge, straightness, elevation and fastener torque, and check whether the joint gap and weld quality meet the requirements. Conduct a no-load test run of the crane first, observe the running stability and wheel contact condition, and then carry out a load test step by step to confirm that there is no abnormal vibration, noise or rail displacement under rated load.
After the acceptance is passed, establish a regular inspection mechanism, check the fastener looseness, rail wear and joint status regularly, and maintain and replace them in time to extend the service life of the track system.
QU120 Crane Rail Technical Parameter Table
- Wide 120mm rail head reduces contact stress and wear
- Thick 44mm web resists deformation under high impact loads
- Low rail height lowers crane center of gravity for better stability
- Multiple material options (U71Mn/U75V) match different working conditions
| Parameter | Value | Unit |
|---|---|---|
| Rail Weight | 118.1 | kg/m |
| Rail Height | 170 | mm |
| Rail Head Top Flat Width | 120 | mm |
| Rail Head Maximum Width | 129 | mm |
| Rail Bottom Width | 170 | mm |
| Web Thickness | 44 | mm |
| Standard Length | 12 | m |
| Default Material | U71Mn | - |
| Tensile Strength (U71Mn) | ≥880 | MPa |
| Yield Strength (U71Mn) | ≥550 | MPa |
| Delivery Hardness (U71Mn) | 260 | HBW |
| Standard | YB/T 5055-2014 | - |
Frequently Asked Questions
Q1: Can QU120 crane rail be used for port STS quay cranes?
Yes, QU120 is specially designed for extreme heavy-duty lifting scenarios3, and is widely used in STS quay cranes, RMG gantry cranes and container terminal rail transport systems. Its wide rail head and thick web structure can withstand the extreme wheel pressure and frequent loading and unloading cycles of port cranes, and can be matched with corrosion-resistant treatment for coastal environments.
Q2: What is the difference between QU120 and QU100 crane rail?
QU120 has a larger cross-section than QU100: the rail head width increases from 100mm to 120mm, the web thickness increases from 38mm to 44mm, and the weight per meter increases from 88.96kg to 118.1kg. QU120 has higher load-bearing capacity and is suitable for occasions where the wheel pressure and impact force exceed the limit of QU100, such as large port cranes and 300-ton shipyard gantry cranes.
Q3: How to choose between bolted joint and welded joint for QU120?
Bolted joints with fishplates are easy to install and disassemble, suitable for temporary tracks or occasions that need frequent adjustment, and the cost is relatively low. Aluminothermic welded joints have smooth surfaces and high strength, which can reduce the impact of wheels on joints, extend the service life of wheels and rails, and are preferred for heavy-duty, high-frequency long-term fixed crane tracks.
Get a quote for QU 120 crane rail
The standard fixed length of QU120 is 12m, which is usually in stock. Special processing such as end chamfering, milling, bevel cutting and curved rail bending can be carried out according to customer drawings.
Each batch of QU120 rail can provide EN 10204 3.1 mill test certificate, which can trace the chemical composition, mechanical properties and batch information of the material. Third-party inspection reports issued by SGS, BV or TÜV can also be arranged according to customer requirements, and non-destructive testing such as ultrasonic testing and magnetic particle testing is carried out according to corresponding standards.