What comprehensive tests do we conduct on rubber-tyred cranes prior to factory release?

Before leaving the factory, rubber-tyred cranes (including RTGs, port-specific rubber-tyred cranes, and mobile rubber-tyred cranes) must undergo a full-process testing regimen in accordance with national standards such as GB/T 6068-2021. This testing covers every dimension—including appearance, structure, chassis, hydraulics, electrical systems, safety, load capacity, stability, travel performance, and reliability. The following outlines the complete testing procedures, which are suitable for direct use in quality inspection protocols and technical tender specifications.

I. Preparatory Inspection (Pre-Test Basic Verification)
Inspection of Overall Appearance and Markings
The frame, boom, outriggers, and cab must be free of deformation, cracks, or dents; the paint finish must be uniform, free of runs or sags, and exhibit adequate adhesion.
Nameplates must be complete and legible, clearly displaying the model number, rated lifting capacity, working radius, manufacturing date, manufacturer details, and complete safety warning signage.
Fasteners, pins, and cotter pins must be present, securely tightened, and reliably secured against loosening.
Measurement of Geometric Parameters
Overall dimensions, wheelbase, wheel track, outrigger span, boom length/radius, and slewing radius are measured and recorded.
The flatness inclination of the slewing bearing mounting surface must be ≤ 0.5%.
Measurement of Mass Parameters
The total machine weight, axle loads, and center of gravity position are determined to ensure compliance with design and transportation requirements.
Inspection of Hydraulic Fluid and Lubricants
The hydraulic fluid grade and cleanliness (particle contamination level) must meet applicable standards; the fluid level in the reservoir must be normal, with no signs of leakage.
Verification of Safety Device Integrity
All safety devices—including torque limiters, load limiters, height/radius limit switches, slewing limiters, brakes, emergency stop buttons, wind-resistance devices, and anti-collision systems—must be present and fully functional.
II. Chassis and Travel System Testing
Chassis Break-in Test
The engine, transmission, drive axles, and steering system undergo a no-load break-in run; no abnormal noises or vibrations should be detected, and temperature rise levels must remain within normal limits.
Travel Performance Testing
Forward and reverse travel, as well as steering, must be smooth and responsive, with no binding or sticking; the steering wheel free play (deadband) must be ≤ 30°.
Braking Performance: Both service brakes and parking brakes must respond rapidly; braking distances and parking-on-grade capabilities must meet specified requirements.
Testing of maximum travel speed, gradeability (climbing capacity), and minimum turning radius. Tire pressure, wear, and suspension system inspection.
Outrigger System Testing
Outrigger extension/retraction, synchronization, and locking reliability verified; leveling function operates normally; outrigger ground bearing pressure measured.
Support stability inspection under full-extension and half-extension outrigger configurations.
III. Hydraulic System Testing
System Pressure and Flow Testing
Main pump and auxiliary pump pressure and flow rates meet specifications; relief valve set pressure is ≤ 110% of the system's rated pressure.
Pressure loss and synchronization testing for each hydraulic circuit.
Sealing Performance Testing
Pressure Retention Test: Pressure held at the rated level for 10 minutes; pressure drop and leakage levels comply with standards.
No external leakage or internal bypass observed in pipelines, fittings, hydraulic cylinders, or valve blocks.
Actuator Operation Testing
Boom extension/retraction, luffing, slewing, and hoisting (lifting/lowering) operations are smooth, free from shock, crawling, or abnormal noises.
Coordination testing for compound movements (simultaneous extension/retraction + luffing + slewing).
Counterbalance Valve and Speed ​​Limiting Function Testing
Controlled lowering of heavy loads is smooth and free from overspeeding; counterbalance valves function reliably to prevent load stalling or uncontrolled descent.
Emergency System Testing
Emergency pump and manual override functions are effective, enabling boom retraction and brake locking in the event of main system failure.
IV. Electrical and Control System Testing
Insulation and Grounding Testing
Insulation resistance of main and control circuits meets standards; grounding resistance is within acceptable limits, and grounding markings are clearly visible.
Electrical Component Function Testing
Emergency stop buttons, switches, indicator lights, horns, and alarm devices operate normally.
Control System Testing
Operation of cab control levers, buttons, and control consoles is responsive, free from delay or unintended actuation.
Wireless Remote Control (if equipped): Testing of operating range, anti-interference capabilities, and automatic shutdown upon signal loss.
Safety Protection Logic Testing
Moment/weight limiter alarms and automatic cutoff functions operate reliably; overcurrent, undervoltage, and overheat protection systems are effective.
Lighting, Signaling, and Monitoring System Testing
Work lights, warning lights, reverse cameras, anemometers, and other systems function normally.
V. No-Load Operation Testing (Core Movement Verification)
Continuous operation involving full boom extension/retraction, full luffing (up/down), and 360° slewing; movements are smooth and free from abnormal noises. The hoisting mechanism performs reliable lifting/lowering, braking, and limit-switching operations under no-load conditions.
All safety limit switches (height, radius, slewing, and travel) trigger accurately and result in immediate machine shutdown.
Noise Testing: Noise levels during no-load operation comply with national standard limits.
VI. Load Performance Testing (Critical Verification)
1. Rated Load Test (100% of Rated Load)
Select typical operating scenarios (maximum radius, intermediate radius, and minimum radius).
Perform compound operations involving hoisting, luffing, slewing, and boom telescoping, running continuously for ≥1 hour.
Inspection: Verify that there is no permanent structural deformation, no cracks in welds, no hydraulic fluid leakage, reliable braking, normal temperature rise, and accurate torque limiter operation.
2. Dynamic Load Test (110% of Rated Load)
Dynamic Impact Scenarios: Perform dynamic operations involving hoisting, braking, luffing, and slewing to verify dynamic structural strength and mechanism reliability.
No abnormal vibration, impact, or instability is permitted.
3. Static Load Test (125% of Rated Load)
Lift the test load 100–200 mm off the ground and hold it suspended in a static position for ≥10 minutes.
Inspection: Verify that there is no plastic structural deformation, no settlement of outriggers, no load slippage from the brakes, and no anomalies in the hydraulic system.
4. Overload Protection Verification
Simulate a load of 105%–110% of the rated capacity to verify that the torque/weight limiter first triggers an alarm and subsequently cuts off hazardous movements.
VII. Whole-Machine Stability Testing
Static Stability
Test with outriggers fully extended/half-extended, at various radii, and at different slewing positions to verify anti-tipping stability.
Under the 125% static load condition, there must be no tendency toward tipping.
Dynamic Stability
During dynamic operations involving dynamic loads, slewing, and luffing, the entire machine must remain stable, without lateral tilting or abnormal swaying.
Wind Protection / Anchoring Test (for Port RTGs)
Verify the reliability of wind protection devices, rail clamps, and anchoring functions.
VIII. Specialized Safety Device Testing
Limit Devices: Verify the accurate operation of height, radius, slewing, and travel limit switches. Brakes: Inspection of braking distance, reliability, and wear for hoisting, luffing, slewing, and traveling brakes.
Moment / Weight Limiter: Verification of accuracy, alarm functions, and cut-off mechanisms.
Emergency Stop: Immediate emergency stop from any position, resulting in instantaneous power disconnection, braking, and locking of all movements.
Power-Loss Protection: Automatic brake engagement upon sudden power failure, ensuring suspended loads do not fall.
Anti-Collision / Alarms: Verification of effective operation for contact-type, radar, and photoelectric anti-collision systems; confirmation of normal audible and visual alarm functionality.
IX. Reliability and Durability Testing
Operational Reliability: Continuous operation under rated load for ≥8 hours, free of faults, abnormal temperature rise, or fluid leakage.
Traveling Reliability: Traveling tests under both full-load and no-load conditions; verification of chassis, suspension, and braking stability.
Temperature Rise Testing: Verification that temperature rise in motors, hydraulic pumps, reducers, bearings, and brakes remains within permissible limits.
X. Comprehensive Factory Acceptance
Final Re-inspection: Review of all test items to ensure data completeness and compliance.
Documentation Review: Verification that inspection records, test reports, certificates of conformity, operation manuals, and spare parts lists are complete.
Cleaning and Protection: Inspection of overall machine cleanliness, protective measures for wear parts, and integrity of paintwork.
Packaging and Shipping Inspection: Verification of secure fastening and adequate protective measures to ensure compliance with transport requirements.
XI. Additional Testing for Specialized Models (As Required)
RTG Container Spreader: Testing of spreader telescoping, twistlock engagement, container landing detection, locking mechanisms, and anti-sway functions.
Grabs / Hooks: Testing of grab opening/closing, gripping force, and discharge functions; inspection of hook safety latches and pulleys.
Explosion-Proof / Anti-Corrosion: Specialized testing for explosion-proof electrical components and anti-corrosion coatings.