Technical Article

How to select the components of the cylinder

1. Cylinder tube

The cylinder tube is the main part of the hydraulic cylinder, so there are requirements in terms of strength, rigidity, and sealing.

(1) The blank of the cylinder tube generally adopts annealed cold-drawing or hot-rolling seamless steel pipes. We can choose C22, C35, C45 and 27SiMn alloy steel.

(2) For hydraulic cylinders whose working temperature is lower than -40℃, C35 or Q345E steel must be used and quenched and tempered.

(3) The cylinder tube welded with the cylinder head or flange can use C35 steel, which can be quenched and tempered after mechanical pre-processing. The cylinder tube that is not welded to other parts uses quenched and tempered C45 steel.

(4) Forgings or steel castings are used for cylinder barrels with thicker walls. Commonly used materials include carbon steel: C20, C35, C45, etc.; ordinary low-alloy structural steels such as 15MnV, 27SiMn, etc.; alloy structural steels such as 30CrMo, 35CrMo, 35CrMo-ALA, etc.; stainless steels such as Cr18Ni9, etc.; aluminum alloys such as ZL105, LF3, LF6, etc.; cast steel such as ZG230-450, ZG310-500, etc.; anti-rust aluminum alloy such as SA03, SA06, etc.

2. Piston rod

There are two types of piston rods: solid rod and hollow rod. Commonly used piston rod materials are C45, 42CrMo, 304, 316L, 1Cr17Ni2, 17-4PH.

3. Cylinder head

Castings for low pressure, HT300 gray iron for low and medium pressure, and C35 and C45 for medium and high pressure.

When the cylinder head is also the guide sleeve of the piston rod, cast iron is best used for the cylinder head. At the same time, brass, bronze or other wear-resistant materials should be melted on the guide sleeve surface. If the structure in which the guide sleeve is pressed into the cylinder head is adopted, the guide sleeve should be made of wear-resistant cast iron, bronze or brass.

4. Piston

Commonly used materials are wear-resistant cast iron, gray cast iron (HT300, HT350), steel and aluminum alloy.