Why is U71Mn steel used to manufacture QU120 crane rails?
QU120 crane rail, standardized under YB/T 5055-2014, is one of the heaviest sections in the Chinese standard crane rail series, with a nominal weight of 118.10 kg/m, a 120 mm rail head width, and a 44 mm web thickness.
High Strength for Heavy Wheel Loads
GNEE RAILWAY RAILWAY supplies QU120 crane rails in U71Mn steel according to YB/T 5055-2014, with a minimum tensile strength of 880 MPa. A supplied MTC records 995 MPa tensile strength and 284 HB hardness, supporting heavy-duty crane runway applications.
Controlled Chemical Composition
U71Mn combines controlled carbon and manganese content for strength and wear resistance. The tested batch contained 0.69% C, 0.41% Si, 1.16% Mn, 0.020% P, and 0.003% S, meeting the specified chemical requirements.
Verified Mechanical Properties
GNEE RAILWAY RAILWAY provides Mill Test Certificates (MTCs) with QU120 rails, allowing buyers to verify steel grade, chemical composition, tensile strength, elongation, hardness, and other applicable inspection data. The referenced certificate specifies a 100–160 metric ton load-capacity range.
Send us your required quantity, rail length, applicable standard, and project specifications for material confirmation and a competitive quotation.
Dimensional and Sectional Properties of QU120 Crane Rail
The QU120 cross-section is engineered with a squat profile (height-to-base ratio of 1:1) to maximize structural stability and lower the center of gravity under dynamic crane traversing loads. Unlike standard UIC or AREMA railway rails, the QU120 profile features a reinforced head and web designed for concentrated vertical and lateral wheel loads.
| Profile Model | Standard | Rail Height (mm) | Bottom Width (mm) | Head Width (mm) | Web Thickness (mm) | Calculated Weight ( kg/m ) |
| QU120 | YB/T 5055-2014 | 170 | 170 | 120 | 44 | 118.10 |
| QU100 | YB/T 5055-2014 | 150 | 150 | 100 | 38 | 88.96 |
| QU80 | YB/T 5055-2014 | 130 | 130 | 80 | 32 | 63.69 |
Get Crane Rail Recommendation & Quote
GNEE RAILWAY RAILWAY supplies a complete range of QU-series crane rails, including QU120, QU100, QU80, and other profiles to meet different crane wheel loads and runway requirements. Buyers can source rails according to the required profile dimensions, weight, standard, length, and project specifications, with precision cutting, drilling, beveling, bending, dimensional inspection, and material certification available for overseas projects.
Operating Envelope and Crane Wheel Matching for QU120
Selecting QU120 rail requires matching wheel load, diameter, material, hardness, and wheel-to-rail contact conditions.
- Applicable Crane Types: STS container cranes, RMG cranes, heavy-duty metallurgical cranes, stacker-reclaimers, and other heavy-load rail equipment.
- Wheel Load: Determine maximum static and dynamic wheel loads from the actual wheel arrangement and load distribution; crane capacity alone is insufficient.
- Wheel Diameter & Material: Select wheel diameter and material according to wheel load, speed, duty cycle, and applicable design standards.
- Wheel Tread Matching: Match the wheel tread and flange geometry to the 120 mm QU120 rail head, ensuring adequate contact area, clearance, and permissible contact stress.
FAQ
Q1: What is the difference between U71Mn and U75V QU120 rails?
A: U71Mn offers a balanced combination of strength, toughness, and weldability, while U75V provides higher strength and hardness. Selection depends on load and service conditions.
Q2: What is the standard length of U71Mn QU120 rail?
A: The standard supply length is 12 m. Custom cut lengths are available according to project requirements.
Q3: Can QU120 rails be drilled on-site?
A: Yes. Suitable heavy-duty rail drilling equipment is required. Factory pre-drilling is recommended for accurate hole positioning.
Q4: How does QU120 compare with DIN 536 A120?
A: Both have a 120 mm head width, but their profiles differ. QU120 is 170 mm high, 170 mm base width, and 118.1 kg/m, while DIN 536 A120 is approximately 105 mm high, 220 mm base width, and 100 kg/m.
Q5: Does U71Mn QU120 require preheating before welding?
A: Yes. Preheating and controlled interpass temperature should follow the approved welding procedure for U71Mn rail to reduce HAZ cracking risks.