Marine Hydraulic Cylinder

Marine hydraulic cylinders are essential components in various maritime applications, designed to withstand corrosive, high-pressure, and demanding operating conditions. These double-acting hydraulic cylinders are engineered to deliver exceptional performance and longevity in marine environments, including offshore platforms, ship handling systems, and underwater equipment.

The construction of a marine hydraulic cylinder begins with a high-strength cylinder barrel, typically made from forged or seamless steel tubes such as SAE4140, SUS316L, or other corrosion-resistant alloys. The inner surface is precision honed to a fine roughness (R0.2–R0.4) and may be chrome-plated for enhanced durability and corrosion resistance. The piston rod, often made from hardened and chrome-plated materials like 42CrMo4 or stainless steel, undergoes surface treatment to achieve a hardness of HRC55–60 and a chrome layer ranging from 20 to 50 microns.

Sealing systems in marine hydraulic cylinders are critical to preventing fluid leakage and ensuring reliable operation. High-quality seal kits from leading brands such as Parker or Merkel are selected based on specific customer requirements and environmental conditions. All welds between the tube and flanges are ultrasonically tested to guarantee integrity and leak-free performance throughout the cylinder's service life.

These marine hydraulic cylinders support design pressures of up to 700 bar and are available in stroke lengths from 50 mm to 16,000 mm. They are widely used in offshore oil and gas engineering, ship steering systems, winches, hatch covers, and other marine machinery. With ISO 9001:2015 certification, our company ensures that every marine hydraulic cylinder is manufactured to exacting standards, offering customized solutions, professional support, and reliable after-sales service to meet the rigorous demands of the marine industry.

JIANGSU YINGNAISI company design and manufacture heavy duty hydraulic cylinders that covering the following fields:

•  hydraulic press cylinder
•  construction machinery cylinder
•  mining machinery cylinder
•  metallurgy machinery cylinder
•  water power project cylinder
•  marine hydraulic cylinder
•  servo hydraulic cylinder

2. Design

Not only we could manufacture all kinds of hydraulic cylinders according to the drawing from our

customers,but also we could make a design according to customer's requirements.If you

require our engineer to make a design,pls advise us the following specification:

1. Rated pressure

2. Working pressure

3. Test pressure

4. Working condition and environment ,for example ,temperature ,working frequency

5. Pulling force ,and return stroke force

6. Pulling and return speed

7. Assembly size

8. Seal ring requirements .For example , brand ,seal material etc .

9. Tube and piston rod raw material requirements

10. Piston rod surface treatment requirements, for example chromating film thickness ,

Surface hardness etc .

11. Painting and other spare parts requirements .

3. Manufacturing capability and cylinder size range

3.1 Cylinder bore diameter :max Ø1200mm

3.2 Cylinder length :10Meter

3.3 Max lifting capability :50 Tons

4.Manufacturing and inspection

4.1.Cylinder tube size and choice

4.1.1 According to the cylinder pressure and inside diameter size ,different steel tube Would be choosed .

1. ID ≤300mm , cold rolled precision seamless tube would be choosed

2. 300mm≤ID ≤500mm , hot rolled seamless tube would be choosed

3. 500mm≤ID ≤1000mm, forged tube would be choosed

4.1.2 Cylinder tube steel grade : SAE1020 , SAE1045 ,27SiMn , S355JR ,S355J2G3

St52-3 ,SUS304 ,SUS316L etc .

4.1.3 Cylinder tube inside boring and honing , roughness R0.2-R0.3,

4.1.4 Cylinder tube inside chromating : if necessary ,tube inside chromating could be applied

.

4.2 Piston rod is a very important part for hydraulic cylinder .

4.2.1 Piston rod steel grade : SAE1045, 42CrMo4, SUS410 ,SUS420, SUS304, SUS316L

4.3 Seal ring and O ring

According to the customers' requirements and working condition , we would choose suitable

seal ring kit , . we would supply suitable seal solution for their customer so that hydraulic cylinder has more

lifetime , easy maintenance and simple repairing .

4.4 Tube and flange welding

The welding on cylinder tube and flange would be Ultrasonic tested every time , the welding seam would be

cleaned before machining .we ensure that every welding seam has no any leak during lifetime

4.5 Assembly and pressure test

Before hydraulic cylinder is assemblied , every spare parts would be measured and cleaned .After hydraulic

cylinder is assemblied , pressure test would be carried out one By one , eternal company ensure that testing

pressure is higher 30%-50% than working pressure , and pressure holding time 30~60 minutes is necessary . Every piece hydraulic cylinder must be tested completely without any leak .

4.6 Painting and storage .

After hydraulic cylinder pass through pressure test , painting is necessary .

4.hydraulic cylinder quality guarantee system

Program before Delivery

1. Trial Operation Test

2. Start-up Pressure Test

3 Pressure-Tight Test

4. Leak Test

5. Full Stroke Test

6. Buffer Test

7. Testing the Effect of Limit

8. Load Efficiency Test

9. Reliability Test

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