What is a Stainless Steel Cylinder?

What is a Stainless Steel Cylinder?

A stainless steel cylinder, as the name suggests, is made from a form of stainless steel; barrels are made from AISI 304, this being the most common austenitic stainless steel. End covers, piston rods and any screws and nuts are made from 303; the addition of sulphur to 303 improves its machinability. Tie-rods are AISI 316; the addition of molybdenum to 316 gives greater corrosion resistance. The cylinder provides linear motion and force in a pneumatic system.


They are also known as...

The term actuator or drive is often used to replace cylinder.


How do stainless steel cylinders work?

Whilst the material used in manufacture is stainless steel, the principle of operation is the same as for other cylinders or actuators. Here we show a typical double acting cylinder. Consider air entering the left port; pressure will act on the left side of the piston, creating a force moving the piston rod out to the right and air will be exhausted through the right port. Now, air supply is switched to the right port; pressure acts on the right side of the piston and retracts the piston rod back into the barrel with air exhausted from the left port.

The arrow in the diagram indicates that the cylinder has adjustable cushioning; the construction of these cylinders allows an air bleed to ‘soften’ the impact of the piston against the end caps. Some cylinders utilise a buffer cushion only and, schematically, the arrow would be omitted from these types.

A valve will be used to control the direction of the flow of air, either in the left port or in the right port. Valves can be manually, mechanically, electrically or air operated, dependent on the application.


How do I select a stainless steel cylinder?

The type and characteristics of the actuator you need is defined by the application you’ll be using it for. Key factors in the selection of a pneumatic cylinder or actuator are:

  • pressure and flow requirements - this should start with a knowledge of the force required from the cylinder and the speed with which it needs to operate. The force required will determine the operating pressure for a given size of cylinder; most manufacturers provide detailed guidance on sizing a cylinder including safety factors that must be included. The flow rate will determine the speed of operation. Consider what you want from the pneumatic actuator or cylinder as this also determines other components required - if they are incorrectly sized they can affect its performance
  • environment - tanks to developments in corrosion-resistance, pneumatic cylinders and actuators can be used in extreme temperatures. Stainless steel actuators or cylinders are particularly suited to harsh environments
  • type dependent on application - roundline and tie-rod cylinders are available as stainless steel options


Types of stainless steel cylinder?


Tie-rod cylinders conform to ISO 15552. They are available in bore sizes from 32mm to 160mm and standard strokes as defined by ISO 15552; non-standard strokes are also available up to the maximum design specification for each bore size. Adjustable cushioning, magnetic piston is standard, but non-magnetic versions are available.

Roundline cylinders conform to ISO 6432. They are available in bore sizes from 12mm to 25mm, with strokes from 5mm to 500mm, dependent on bore size. Magnetic piston is standard, but they are available as buffer cushioning across the majority of the range (check datasheet for variants) and adjustable cushion for 20mm and 25mm bore size (again, check datasheet for variants).


Typical applications for a stainless steel cylinder?

Stainless steel cylinders are ideally suited to applications where the working environment can be hostile – for example, hot with aggressive chemicals. The Food & Beverage sector is a regular user of stainless steel, due to the often caustic wash-down procedures.


Do I need anything else for a stainless steel cylinder?

Relevant accessories include mounting systems, and additional detection systems should there be a more precise degree of positioning required. Actuators or cylinders can be mounted in a variety of ways, including foot mounts and neck mounts depending on the size of the operation and type of actuator or cylinder used.

A pressure regulator to control the air pressure, as well as rigid or flexible tubing, the appropriate fittings, gauges and sensors are also required. To control the speed of the actuator, a flow regulator can be used at the point of use.


More information

Browse our range of stainless steel cylinders to find out more