ISO 24819:2019 Crane End Carriage Technical Requirements Explained
ISO 24819:2019, "Cranes — Technical Requirements for End Carriages," defines the engineering standard for crane end carriages. It specifies material grades (Q345B or Q420B with box or I-beam cross-sections), connection methods (high-strength bolts ≥M20 with friction-type contact surfaces, sandblasted to a friction coefficient ≥0.45, or full-penetration welding with UT Level I acceptance), key tolerances (overall length ±3 mm, center distance ±1.5 mm, diagonal difference ≤2 mm, connection surface flatness ≤0.5 mm), wheel seats (Φ250–800 mm, hardness ≥300 HB), and Factory Acceptance Test requirements.
Technical Requirements for Crane End Carriages
End carriages are fabricated from Q345B or Q420B steel in either a box or I-beam cross-section. When bolted to the main girder, high-strength bolts of at least M20 are used in a friction-type connection. The contact surfaces are sandblasted to achieve a friction coefficient of no less than 0.45, and the pre-tightening torque is applied per the design value and verified with a torque wrench to within ±5%. For welded connections, full-penetration welds must pass UT flaw detection to Level I. Crane bridge wheel seats are provided at both ends to accommodate wheel diameters from Φ250 to 800 mm, with wheel flange hardness of at least 300 HB. The diagonal difference of the end carriage—defined as the difference between the two diagonal lengths across the main girder ends—must not exceed 5 mm.
Inspection Requirements and Tolerances
Critical tolerances for the end carriage include: overall length deviation of ±3 mm, center distance deviation between the two wheel seats of ±1.5 mm, diagonal difference across the wheel seats of ≤2 mm, and flatness of the connection surface to the main girder of ≤0.5 mm. The Factory Acceptance Test covers visual inspection, dimensional verification, torque spot-checking on 10% of the bolts, and flaw detection. After installation, the alignment difference between the two crane bridge wheels on the same side must be ≤2 mm, and the contact plane deviation across all four wheels must be ≤3 mm. Every end carriage shipped by Kelude Heavy Industry is accompanied by a dimensional inspection report and a weld NDT report.
| Item | Requirement |
|---|---|
| Material | Q345B (≈S355J2)/Q420B |
| Connection | High-Strength Bolt M20+ |
| Weld Seam | Full Penetration UTⅠClass |
| Crane wheel | Φ250~800mm |
| Hardness | ≥300HB |
| diagonal difference | ≤5mm |
| Inspection | Period |
|---|---|
| factory | unit by unit |
| Annual Inspection | Annually |
The end carriage is a critical structural component of a bridge crane, connecting the main girders and supporting the crane bridge wheels. Its primary function is to transmit vertical and horizontal loads from the main girders to the crane bridge wheels. Manufactured from Q345B or Q420B steel with a box or I-beam cross-section, the end carriage provides the required strength and stiffness. The connection between the end carriage and the main girder is achieved either through high-strength bolting or welding. For bolted connections, friction-type high-strength bolts of M20 or larger are used. The faying surfaces are sandblasted to achieve a friction coefficient of at least 0.45, ensuring a reliable connection. For welded connections, full penetration welds are applied and must pass UT flaw detection to Class I standards. Crane bridge wheel seats are mounted at both ends of the end carriage, accommodating wheel diameters from Φ250 to 800 mm. The wheel flange hardness is a minimum of 300 HB to ensure wear resistance. Key manufacturing tolerances include: overall length deviation of ±3 mm, center distance deviation between the two wheel seats of ±1.5 mm, and a diagonal difference between wheel seats of ≤2 mm. Kelude Heavy Industry manufactures end carriages in accordance with ISO 24819, and each unit is supplied with a dimensional inspection report and a weld seam NDT report.
End Carriage Manufacturing Standards & Tolerances
Q: What are the material and connection requirements for end carriages under ISO 24819:2019?
A: End carriages are fabricated from Q345B or Q420B steel with a box or I-beam cross-section. Two connection methods to the main girder are available: high-strength bolting (friction-type bolts ≥M20, sandblasted faying surfaces with a friction coefficient ≥0.45, and pre-tightening torque applied per design values, verified with a torque wrench to ±5%) or welding (full penetration welds passing UT flaw detection to Class I).
Q: What are the critical tolerance requirements for end carriages?
A: The key tolerances are: overall length deviation of ±3 mm, center distance deviation between the two wheel seats of ±1.5 mm, diagonal difference between wheel seats of ≤2 mm, and flatness of the connection surface to the main girder of ≤0.5 mm. After installation, the alignment difference of the crane bridge wheels must be ≤2 mm, and the contact plane difference across all four wheels must be ≤3 mm. These tolerances directly impact the crane's operating stability and wheel service life.
Q: What does the Factory Acceptance Test for end carriages include?
A: The Factory Acceptance Test covers visual inspection of weld dimensions and surface quality, verification of critical dimensions (overall length, center distance, diagonals), and torque spot checks on 10% of the high-strength bolts. Each end carriage is shipped with a dimensional inspection report and a weld seam NDT report. Post-installation checks verify the crane wheel alignment difference is ≤2 mm and the four-wheel plane difference is ≤3 mm.
Q: What manufacturing standard does Kelude follow for end carriages?
A: Kelude Heavy Industry manufactures end carriages for both bridge and gantry cranes in accordance with ISO 24819:2019, using Q345B/Q420B steel with a box cross-section. The connection method—high-strength bolting or full penetration welding (UT Class I)—is selected based on customer requirements. Each unit is supplied with a dimensional inspection report and a weld seam NDT report.
