Custom Welded Hydraulic Cylinders

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

 

Welded hydraulic cylinders are built for heavy-duty industrial and mobile applications where compact envelope dimensions, structural rigidity, and resistance to fatigue are mandatory. Unlike tie-rod designs that rely on external threaded rods held under tension, welded cylinders feature heavy-walled seamless steel tubes directly welded to steel end caps and mounting flanges. This eliminates tie-rod stretch under high pressure, prevents barrel deformation, and reduces the overall outer profile for installation in tight equipment frames.

Manufactured to custom OEM specifications, these linear actuators operate under working pressures up to 35 MPa (5,076 PSI) and impulse peak loads. Designed for continuous duty in construction, agricultural, mining, and material handling machinery, each unit is built with high-yield strength materials, precision-honed tube bores, and application-specific sealing configurations to prevent external leaks and internal fluid bypass.

 

 

Parameter	Standard Range / Technical Options
Bore Size Range	20 mm to 300 mm (0.78" to 11.81")
Piston Rod Diameter	12 mm to 220 mm (0.47" to 8.66")
Stroke Length	Up to 6,000 mm (236.22")
Operating Pressure	Continuous: 16 – 35 MPa (2,320 – 5,076 PSI) Peak/Shock: Up to 42 MPa (6,090 PSI)
Operating Temperature	Standard Seals: -20°C to +80°C (-4°F to +176°F) High Temp Seals: -20°C to +200°C (-4°F to +392°F) Low Temp Seals: -45°C to +80°C (-49°F to +176°F)
Barrel Material	ST52-3, E355, 4140, or 20# Seamless Cold Drawn Steel Tube
Internal Bore Finish	Honed finish, Ra ≤ 0.2 µm – 0.4 µm
Piston Rod Material	C45 (1045), 42CrMo4 (4140), 20MnV6
Piston Rod Plating	Hard chrome plating, minimum thickness 25 – 30 µm; Surface hardness ≥ 850 HV; Corrosion resistance ≥ 96h to 500h NSS (ISO 9227)
Sealing System	Parker, Hallite, NOK, or Merkel high-pressure polyurethane and PTFE step seals
Hydraulic Media	Mineral oil, water-glycol, synthetic esters, biodegradable hydraulic fluids

 

 

Rigid Welded End-Cap Construction
End caps, mounting trunnions, and clevises are joined to the honed barrel via automated submerged arc or robotic GMAW welding. Full-penetration welds undergo ultrasonic inspection to ensure 100% structural integrity under cyclic fatigue loads.
Low-Friction Precision Bore
Seamless cold-drawn steel tubes are stress-relieved and precision-honed. Straightness tolerances within 1:1000 mm minimize seal friction, reduce internal bypass, and prevent premature gland degradation.
Corrosion & Wear-Resistant Rod Surface
Piston rods are precision induction-hardened (HRC 52–58) to resist denting from stone impacts or mechanical wear, then ground and micro-finished before hard chrome plating. Stainless steel rods (316 / 17-4PH) or nickel-chrome dual-layer coatings are available for marine or salt-spray environments.
Multi-Stage Gland & Seal Package
The rod gland features a primary U-cup pressure seal, a secondary buffer ring with pressure relief channels, and a polyurethane wiper seal to exclude dirt, mud, and moisture. Wear rings prevent metal-to-metal contact between the rod gland, piston, and cylinder wall under severe side loads.
Integrated Hydraulic Cushioning
Adjustable or fixed deceleration cushions at either end of the stroke limit impact velocity, reducing structural shock and machine noise during fast extension or retraction cycles.

 

 

To suit varied equipment geometries and operating duty cycles, mechanical and hydraulic parameters are engineered across three main criteria:
Mechanical Layout & Kinematics
Retracted and extended pin-to-pin distance constraints.
Mounting geometry, swivel angle requirements, and clearance envelopes.
Custom port angular positions and rod end thread geometries.

Hydraulic Load & Duty Cycle
Buckling resistance verification based on rod length, push force, and system peak loads.
Continuous operating pressure vs. dynamic shock loads.
Stroke speed regulation and internal oil flow volume.

Environmental & Application Safeguards
Wide-spectrum thermal isolation via custom seal compound selection.
Side-load absorption via heavy-duty internal wear rings to protect the gland housing and bore wall.
Integrated valve blocks (counterbalance valves, pilot-operated check valves, or pressure relief valves) manifold-mounted directly onto the cylinder barrel.

 

 

Category	Customization Scope
Mounting Styles	Clevis with spherical bearings, cross tube with grease fittings, front/rear flange, trunnion (mid-barrel, head, or cap), foot mounts, pin eyes.
Rod End Style	Female thread, male thread, spherical tie-rod eye, cross-tube, welded clevis, custom flange.
Port Types	SAE J1926-1 (ORB), ISO 1179-1 (BSPP), ISO 6149-1, SAE J518 Flange (Code 61/62), or custom manifold faces.
Integrated Components	Linear position sensors (magnetostrictive/inductive), proximity switches, counterbalance valves, velocity fuses, burst valves.
Paint & Protective Coatings	Standard epoxy primer, polyurethane topcoats, C3-C5 marine anti-corrosion paint systems, thermal spray coatings (metalizing), black oxide, nitriding.

 

 

The production line follows tight quality control gates from raw material arrival to final assembly:
Material Selection & Sourcing: Seamless steel tubes and solid rod stock undergo chemical composition analysis and ultrasonic flaw detection before processing.
CNC Machining & Precision Honing: Tube blanks are cut, faced, and internally honed to precise dimensional tolerances and micro-inch surface finishes. Rods are turned on CNC lathes, threaded, and prepared for heat treatment.
Heat Treatment & Surface Plating: Piston rods undergo high-frequency induction hardening followed by hard chrome plating and multi-stage polishing to reach surface requirements.
Automated Welding: Tube ends, flanges, ports, and end mounts are joined using automated robotic GMAW or submerged arc welders with controlled pre-heating and weld parameters.
Assembly in Clean Environment: Machined components undergo ultrasonic washing. Assembly occurs in cleanroom bays to prevent particulate contamination from damaging seals or cylinder bores.

 

 

Every manufactured cylinder undergoes testing prior to packaging to ensure zero-defect delivery:

Test Type	Test Parameters	Pass Criteria
High-Pressure Hydrostatic Proof Test	1.5x maximum rated pressure held for minimum 3–5 minutes	Zero pressure drop over specified hold time
Internal Bypass / Leak Test	Rated pressure applied across piston head in fully extended and retracted positions	Zero seal bypass flow measured at return port
Low-Pressure Breakout Test	0.5 – 1.0 MPa fluid pressure actuation	Smooth movement; no stick-slip behavior
Weld Integrity (NDT)	Ultrasonic & dye-penetrant NDT on all structural load welds	No porosity, cracks, or lack of fusion
Fluid Cleanliness Verification	Particle counter audit during flush cycles	ISO 4406 code 16/14/11 or better

 

 

To receive an accurate engineering proposal and commercial quotation within 24–48 hours, provide the following parameters:
Key Dimensions: Bore size, rod diameter, stroke length, and closed pin-to-pin distance (retracted length).
Operating Pressure: Normal working pressure and maximum system peak/shock pressure.
Mounting Configuration: Mount types for cap end and rod end (e.g., cross tube, clevis, pin eye, flange, trunnion).
Port Requirements: Thread type, thread size, and angular location relative to mounting pins.
Environmental Factors: Operating temperature range, exposure to saltwater, chemicals, or outdoor abrasive dust.
Volume & Delivery Schedule: Initial sample requirement, batch quantity, and estimated annual usage (EAU).
Engineering Drawings: 2D (PDF/DWG) or 3D CAD files (STEP/IGES), if available.

 

 

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