Large Bore Hydraulic Cylinders

Tonghesheng Machinery is one of the competitive manufacturers and suppliers of high-quality large bore hydraulic cylinders, and we are also equipped with a professional factory, welcome to buy large bore hydraulic cylinders products from our company.

 

Large bore hydraulic cylinders are engineered for applications requiring high linear force output and structural rigidity under extreme operating loads. Designed with bore diameters ranging from 200 mm to over 800 mm, these heavy-duty actuators deliver reliable push and pull forces in demanding environments such as mining equipment, industrial presses, marine engineering, and heavy infrastructure projects.

Built with thick-walled seamless steel tubing, precision-ground induction-hardened piston rods, and heavy-duty sealing systems, these cylinders maintain pressure integrity and alignment under severe side-loading, shock loads, and high working pressures up to 35 MPa (350 bar).

 

 

Parameter	Specification Range / Standard
Bore Diameter	200 mm – 800+ mm (8 in – 32+ in)
Piston Rod Diameter	100 mm – 500+ mm
Max Stroke Length	Up to 12,000 mm (12 meters)
Nominal Operating Pressure	16 MPa – 35 MPa (160 bar – 350 bar)
Proof Test Pressure	Up to 1.5x Nominal Pressure (e.g., 52.5 MPa max)
Operating Temperature	Standard: -20°C to +80°C (High-temp option: -10°C to +200°C)
Tube Material	ST52-3, 27SiMn, 42CrMo, 1045 seamless steel tubing
Rod Material	45# Steel, 42CrMo4, Stainless Steel (316 / 17-4PH)
Rod Surface Treatment	Hard chrome plating (min 20–50 µm), Nickel-Chrome plating, or HVOF thermal spray
Tube Internal Surface	Honed / Skived & Roller Burnished (Ra <= 0.4 µm)
Sealing System	Parker, Hallite, NOK, or Trelleborg multi-stage high-pressure seals
Fluid Compatibility	Mineral oil (HLP), Water-glycol (HFC), Synthetic ester (HFD-U)

 

 

High-Strength Barrel Construction: Heavy-wall cold-drawn or hot-rolled seamless alloy tubing, stress-relieved prior to finish honing to ensure dimensional stability under peak expansion pressures.
Corrosion & Wear Resistant Rod Coating: Induction-hardened piston rods plated with hard chrome or duplex Nickel-Chrome layers to withstand harsh marine or abrasive outdoor conditions.
Heavy-Duty Retention Gland: Bolted gland designs using high-tensile fasteners to simplify field maintenance, replace internal seals, and withstand cyclic fatigue loading.
Integrated Cushioning Mechanism: Adjustable end-position cushions at both head and cap ends reduce mechanical impact deceleration, protecting equipment frames and extending seal life.
Multi-Stage Sealing Configuration: Primary U-cup polyurethane seals, secondary low-friction PTFE energized seals, anti-extrusion bronze-filled PTFE wear rings, and double-lip wiper seals to prevent fluid bypass and external contamination ingress.

 

 

Operating large bore cylinders requires careful evaluation of structural and fluid dynamics to prevent premature failure:
Column Buckling (Stroke-to-Rod Ratio): Long strokes under push load are susceptible to rod buckling. Design calculations strictly adhere to Euler column strength formulas to determine safe maximum working strokes based on mounting geometry.
Side Loads and Deflection: External mechanical forces cause rod bending and localized seal wear. High-load bearing rings made of bronze or fabric-reinforced resin are integrated into the gland and piston to distribute lateral forces.
Pressure Spikes and Shock Loading: Rapid valve closures or sudden structural drops generate internal shock pressures up to 150% of nominal rating. Cylinder walls and flange welds are stress-analyzed using Finite Element Analysis (FEA) to endure fatigue cycles.
Thermal Expansion: Extended duty cycles in enclosed spaces increase fluid temperatures. Seal compound selection (Fluorocarbon/FKM vs. Polyurethane/AU) is matched to actual continuous operating temperature and hydraulic fluid chemistry.

 

 

Mining & Earthmoving Equipment: Primary dump hoist cylinders, shovel arm actuators, jaw crusher tensioning systems, and subterranean tunneling machinery.
Metal Processing & Forging: Steel mill roll gap adjustment cylinders, heavy hydraulic press main rams, continuous casting equipment, and scrap balers.
Marine & Offshore Engineering: Hatch cover actuators, offshore crane luffing cylinders, motion compensators, and dredging bucket arms.
Civil Infrastructure & Hydraulics: Hydroelectric dam spillway gate hoists, movable bridge opening mechanisms, and heavy shield tunneling equipment.

 

 

Material Selection & Inspection: Raw seamless steel tubes and solid bar stock undergo ultrasonic flaw detection and heat treatment batch verification (chemical composition and mechanical strength certificates).
Machining & Deep Hole Drilling: CNC lathes turn outer diameters, while deep-hole boring machines rough-cut large inner diameters.
Honing & Skiving: Inner tube surfaces are skived and roller-burnished or deep-honed to achieve roundness, straightness, and a surface roughness profile of Ra <= 0.2 – 0.4 µm.
Rod Processing: Piston rods undergo heat treatment (quenching and tempering), high-frequency induction hardening (HRC 52–58), precision cylindrical grinding, and automated chrome electroplating.
Welding: Critical structural welds (flanges, trunnions, end caps) are performed via submerged arc welding (SAE/AWS certified operators) followed by non-destructive testing (NDT).
Final Assembly: Components are cleaned in ultrasonic wash stations and assembled in cleanroom environments to prevent contamination.

 

 

Every large bore hydraulic cylinder undergoes rigorous quality verification before shipment:
Non-Destructive Testing (NDT): 100% Magnetic Particle Inspection (MPI) on welded joints; Ultrasonic Testing (UT) on raw forgings and rod materials.
Dimensional & Surface Finish Checks: CMM measurement of critical mounting hole tolerances and surface roughness tester verification of rod and bore finishes.
Salt Spray Testing: Chrome plating samples undergo 96 to 500-hour neutral salt spray (NSS) testing (ASTM B117 / ISO 9227) based on corrosion resistance grade.

Hydrostatic Pressure Testing:
Low-pressure leakage check at 0.5 MPa.
Internal bypass leakage testing across piston seals at nominal working pressure.
Proof-pressure testing held at 1.3x – 1.5x working pressure for 30 minutes to verify structural integrity.
Cleanliness Verification: Fluid flush sampling analyzed per ISO 4406 cleanliness standards (target code 16/14/11 or better).

 

 

To receive an accurate engineering proposal and commercial offer, please submit the following operational parameters:
Bore Size and Rod Diameter (or required push/pull force at available system pressure)
Stroke Length and maximum extended overall installation length
Maximum Working Pressure and peak system shock pressure
Mounting Style (Head flange, rear clevis, trunnion, etc., including pin size constraints)
Operating Environment (Ambient temperature, outdoor exposure, marine atmosphere, dust level)
Working Medium (Standard mineral oil, water-glycol, synthetic ester)
Duty Cycle & Speed (Frequency of extension/retraction, stroke speed in mm/s)
Special Requirements (Integrated linear transducers, load-holding valves, specific paint coating specs, third-party inspection certifications like ABS, DNV, Lloyd's)

 

 

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