The materials used to manufacture hydraulic components are almost as varied as the uses of hydraulics themselves. Depending on the usage the components are being put to, you will find varying materials, determined by the exact requirements for strength, flexibility, and resistance to corrosion and internal pressure.
For example, most consumer-grade hydraulic devices (like bottle jacks for passenger cars) will have a cylinder made of steel or aluminum. As the required tolerance for pressure per square inch increases, so does the durability of the cylinder material. More durable construction materials include carbon steel, aluminum alloys when weight reduction must be factored in, and even composite materials when resistance to rust or other corrosion is important. Cylinders can also be externally treated with polishing or burnishing, and in some cases even chemically treated with coatings of zinc, tin, and even “diamond-like coatings” (DLCs) for especially high-tolerance components, with an attendant cost increase.
Interestingly, the internal portion of the hydraulics and the piston is almost never made of advanced materials, such as those described for the cylinder. Instead, pistons are almost universally constructed from some variety of steel or cast iron, for maximum durability. However, the piston rod, being exposed to external conditions, vibration, and high friction, is frequently made from steel, stainless steel, or even more advanced materials, like polymers.
The materials science behind hydraulics components can be overwhelming and confusing, but it is of critical importance nonetheless when selecting the correct components for your requirements. Texas Hydrostatics understand hydraulics materials science in and out, and can help you make economical and safe choices when selecting parts for your hydraulics equipment.