| Cylinder Barrel |
Cold-drawn honed steel tube; commonly low-carbon or medium-carbon steel |
Typical tensile strength: approximately 350–700 MPa, depending on grade and heat treatment.
Honed internal surface roughness is commonly about Ra 0.2–0.4 µm.
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High structural strength, good dimensional stability, reliable sealing surface, and efficient production.
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Requires corrosion protection; poor surface finish or ovality can accelerate seal wear and leakage.
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General industrial machinery, mobile equipment, lifting systems, and agricultural machinery.
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High |
Check internal diameter tolerance, roundness, wall thickness, honing pattern, surface roughness, and corrosion protection.
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| Corrosion-Resistant Cylinder Barrel |
Austenitic stainless steel, such as 304 or 316 family alloys |
Typical tensile strength: approximately 515–620 MPa for common annealed grades.
Strong resistance to atmospheric corrosion; molybdenum-bearing grades provide improved resistance to chlorides.
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Excellent corrosion resistance, clean appearance, and suitability for washdown or humid environments.
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Higher material cost, lower hardness than hardened alloy steel, and possible galling during sliding contact.
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Food-processing surroundings, marine environments, chemical handling areas, and outdoor equipment.
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High |
Confirm alloy designation, passivation condition, bore finish, weld quality, and resistance to the actual fluid or atmosphere.
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| Piston Rod |
Alloy steel with hard-chrome, nickel-chrome, or advanced corrosion-resistant surface treatment |
Typical base-material tensile strength: approximately 800–1,200 MPa after suitable heat treatment.
Surface hardness and coating thickness vary by process and duty.
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High bending resistance, good fatigue performance, low friction, and improved wear resistance when properly finished.
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Coating damage, impact marks, or inadequate protection can cause pitting, seal damage, and premature leakage.
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High-cycle cylinders, construction equipment, presses, material-handling systems, and outdoor machinery.
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High |
Inspect straightness, diameter, surface roughness, coating continuity, hardness, corrosion resistance, and thread quality.
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| Corrosion-Resistant Piston Rod |
17-4 PH precipitation-hardening stainless steel or equivalent corrosion-resistant alloy |
Typical tensile strength: approximately 930–1,310 MPa, depending on aging condition.
Offers substantially higher strength than many annealed stainless grades.
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Strong combination of mechanical strength, dimensional stability, and corrosion resistance.
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More expensive and more sensitive to heat-treatment condition and surface-finishing quality.
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Marine equipment, offshore systems, chemical environments, and high-value outdoor machinery.
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High |
Verify heat-treatment condition, hardness, passivation or coating, surface finish, and compatibility with chloride exposure.
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| Piston |
Ductile iron, carbon steel, or alloy steel |
Typical tensile strength: approximately 400–1,000 MPa, depending on material and treatment.
Requires accurate groove geometry for piston seals and wear elements.
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Good compressive strength, resistance to pressure loading, and compatibility with many hydraulic-fluid systems.
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Ferrous materials add weight and require corrosion control; incorrect groove dimensions can damage seals.
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General-purpose cylinders, heavy-duty actuators, presses, and high-load applications.
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High |
Check concentricity, piston-to-bore clearance, groove dimensions, material hardness, and surface finish.
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| Piston Seal |
Polyurethane, NBR, PTFE-based compound, or other application-specific elastomer |
Typical continuous temperature capability varies widely: approximately −30 to 100 °C for many polyurethane or NBR compounds, and up to about 200 °C for selected PTFE compounds.
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Controls internal leakage and maintains pressure separation between cylinder chambers.
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Temperature, fluid chemistry, extrusion gap, pressure, and installation damage strongly affect service life.
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Select according to hydraulic fluid, pressure, speed, temperature, and dynamic sealing requirements.
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High |
Confirm seal profile, hardness, temperature range, fluid compatibility, extrusion resistance, and correct installation direction.
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| Rod Seal |
Polyurethane, NBR, PTFE-based compound, or fluorocarbon elastomer |
Designed for dynamic reciprocating motion.
Temperature capability commonly ranges from approximately −30 to 200 °C, depending on compound and design.
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Prevents external hydraulic-fluid leakage and helps exclude contaminants from the cylinder.
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Excessive rod runout, poor surface finish, contamination, pressure spikes, and incorrect seal geometry reduce life.
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All hydraulic cylinders, especially mobile equipment and high-cycle actuators.
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High |
Check rod surface roughness, seal lip condition, pressure rating, wiper integration, and compatibility with the hydraulic fluid.
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| Rod Guide and Wear Ring |
Filled PTFE, engineered thermoplastic, or fabric-reinforced composite |
Low-friction sliding materials with good wear resistance when correctly matched to load, speed, and lubrication conditions.
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Supports the rod, reduces metal-to-metal contact, and helps control lateral loads.
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Excessive side loading, high temperature, contamination, or incorrect clearance can cause deformation and accelerated wear.
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Long-stroke cylinders, mobile equipment, high-cycle systems, and applications with moderate side loading.
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High |
Verify bearing load capacity, clearance, material compatibility, wear pattern, and resistance to extrusion.
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| Rod Wiper |
Polyurethane, NBR, or reinforced thermoplastic elastomer |
Usually selected for abrasion resistance and elastic recovery rather than pressure sealing.
Temperature capability depends on compound and profile.
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Removes mud, dust, water, and other contaminants from the rod before retraction into the cylinder.
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A damaged or overly tight wiper can increase friction and generate heat; it is not a substitute for a pressure seal.
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Construction equipment, agricultural machinery, outdoor actuators, and dirty operating environments.
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High |
Inspect lip geometry, interference, contamination retention, rod compatibility, and resistance to low temperatures.
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| Gland and Cylinder Head |
Carbon steel, ductile iron, alloy steel, or stainless steel |
Typical tensile strength ranges from approximately 400–1,200 MPa, depending on alloy and heat treatment.
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Retains seals and guides, transfers loads, and provides a serviceable interface for rod and port components.
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Poor alignment or inadequate thread and groove accuracy can create leakage, uneven wear, and difficult maintenance.
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Serviceable cylinders, heavy-duty systems, and designs requiring replaceable seal cartridges.
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High |
Check concentricity, thread accuracy, seal-groove dimensions, port integrity, hardness, and corrosion protection.
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| Tie Rods or Cylinder Fasteners |
High-strength alloy steel, commonly quenched and tempered |
Typical tensile strength: approximately 800–1,200 MPa for many high-strength fastener grades.
Correct preload is essential for maintaining cylinder integrity.
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Maintains barrel, heads, and end components under pressure and simplifies disassembly for service.
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Incorrect tightening, thread damage, corrosion, or fatigue can lead to joint separation or leakage.
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Industrial tie-rod cylinders, repairable cylinders, and systems requiring regular maintenance.
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Medium |
Verify grade, thread condition, torque or preload, elongation, corrosion protection, and nut engagement.
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| Ports and Hydraulic Connections |
Carbon steel, stainless steel, or compatible ductile iron |
Material selection depends on working pressure, fatigue loading, corrosion exposure, and connection standard.
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Provides reliable hydraulic-fluid entry and exit while supporting pressure containment and service connections.
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Incorrect thread standards, poor alignment, over-tightening, and contamination can cause leakage or component damage.
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All hydraulic cylinders; stainless materials are preferred for corrosive or washdown environments.
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High |
Confirm port standard, pressure rating, thread engagement, sealing method, cleanliness, and material compatibility.
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| Protective Rod Coating |
Hard chrome, nickel-chrome, thermal-spray alloy, or other engineered surface treatment |
Coating thickness, hardness, porosity, and adhesion vary by process and must be specified for the intended duty.
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Improves wear resistance, corrosion protection, surface hardness, and seal-running performance.
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Coating defects, poor adhesion, cracking, or excessive roughness can shorten seal life and expose the base metal.
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Abrasive, humid, high-cycle, and outdoor environments where rod durability is critical.
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High |
Measure coating thickness, adhesion, hardness, porosity, surface roughness, and resistance to the operating environment.
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