Hydraulic Cylinders

Verified by Mel Sykes, Industrial Supply Chain Specialist - April 2026

Specification	Details
Types	Single acting, double acting, telescopic, plunger
Bore sizes	16mm to 500mm
Pressures	160 bar to 350 bar
Standards	ISO 6020/6022 (industrial), ISO 4393 (mobile)

What are Hydraulic Cylinders?

Hydraulic cylinders convert hydraulic energy into mechanical force and motion, often used in manufacturing and construction machinery. They consist of a cylinder barrel, piston, rod, and seals.

Hydraulic cylinders are important components that use pressurised fluid to generate linear movement and force. These devices typically include a cylindrical barrel, a piston housed inside the barrel, a rod connected to the piston that extends out of one end of the barrel, and various sealing mechanisms to prevent leakage. The cylinder operates by injecting hydraulic fluid into the chamber, pushing the piston forward or backward depending on the direction of the fluid flow.

Types and Variants

Hydraulic cylinders come in several types, each suited for different applications:

• Single Acting: Works with pressure from one side only, using a spring to return the rod. Common bore sizes range from 16mm to 500mm, with pressures up to 350 bar.

• Double Acting: Operates bi-directionally; force can be applied on both extension and retraction strokes. These cylinders have higher pressure ratings, typically between 160 bar and 350 bar.

• Telescopic: Features nested concentric tubes that extend to provide a longer stroke length in compact packaging. Suitable for applications requiring long extensions but limited space, such as excavators.

• Plunger (Ram): Simplest type with no rod; the entire cylinder extends under pressure and retracts when fluid is released or pushed back by spring force. Bore sizes range from 25mm to 100mm.

Materials and Specifications

Hydraulic cylinders are manufactured using a variety of materials to meet different performance requirements:

• Barrels: Typically made from EN8 carbon steel, which meets BS EN ISO 6937 standards for mechanical properties. Stainless steel A2-70 is also used in corrosive environments.

• Pistons and Rods: Often constructed with high-grade stainless steel like AISI 316 or carbon steels such as SAE 4140, ensuring durability under extreme conditions.

• Seals: Made from nitrile rubber (NBR) or polyurethane to withstand temperatures between -25°C and +80°C. Some advanced designs use Viton seals for higher temperature ranges up to 130°C.

Selection Criteria

Choosing the right hydraulic cylinder involves considering several factors:

• Load Requirements: Determine the maximum force needed and select a cylinder that can handle at least 10% more than this value.

• Stroke Length: Measure the required stroke length, ensuring the chosen cylinder offers sufficient extension/retraction without compromising performance.

• Environmental Conditions: Assess operating temperatures and exposure to corrosive substances. Opt for materials like stainless steel or zinc-plated components in harsh environments.

UK Suppliers

MLC lists verified suppliers from Companies House that adhere to industry standards. For instance, CBM (Chartered Body of Maintenance) members offer cylinders with strong quality control measures. BIAFD (British Industrial Automation and Fluid Power Distributors Association), BTMA (British Technical Manufacturers' Association), and BPMA (British Pump Manufacturers' Association) also provide a list of reliable suppliers that meet ISO 9001 standards.

Common Applications

Hydraulic cylinders are widely used across various industries:

• Manufacturing: For press machines, stamping operations, and automated systems. Bore sizes range from 25mm to 300mm with pressures up to 350 bar.

• Construction: In excavators, bulldozers, and cranes where large stroke lengths are required for heavy lifting tasks. Telescopic cylinders are preferred due to their compact design.

• Automotive: For vehicle lifts in service stations and body shops. Single acting or double acting cylinders with bore sizes up to 100mm are commonly used here.

• Agriculture: On tractors and harvesters where precise control of hydraulic implements is important. Plunger cylinders often provide the necessary force for these applications.

By understanding these specifications, engineers can select the most appropriate hydraulic cylinder based on their specific needs and operating conditions.