The cylinder barrel is the main body of the hydraulic cylinder to withstand a lot of hydraulic pressure, there should be sufficient strength and stiffness. The cylinder barrel, cylinder cap, and sealing device constitute a hydraulic cylinder sealing working volume, so the cylinder barrel should have reliable sealing. Sometimes, it is necessary to weld the oil port, flange, and other components on the cylinder barrel, which requires that the materials of the cylinder barrel also have great welding performance.
The Common Material of Cylinder Barrel
Cylinders (or barrels) are made of steel; usually carbon steel. In terms of strength, a range of different steels are available, with higher pressures requiring stronger steel and thicker cylinder walls.
The inside diameter of the tube usually does not need to be protected by paint or chrome, as the hydraulic oil protects it from corrosion. However, if the hydraulic oil is a corrosive material (e.g., water), the inside of both the tube and the rod will be coated
The cylinder steel pipe is made up of carbon C, silicon Si, manganese Mn, sulfur S, phosphorus P, and chromium Cr. Steel is classified into three types based on its carbon content: low-carbon steel, medium-carbon steel， and high-carbon steel. Low-carbon steel has a carbon content of less than 0.25%, medium-carbon steel has a carbon content between 0.25 and 0.60%, and high-carbon steel has a carbon content greater than 0.60%.
- 20 # steel pipe: 20 refers to the carbon content of 0.2% and belongs to the low carbon steel. The steel has low strength, toughness, plasticity, and weldability.
- 35 # steel pipe: with an average carbon content of 0.35% or so, is medium-carbon steel.
- 45 # steel pipe: carbon content of about 0.45% for medium carbon steel.
These materials increase the carbon content to achieve the purpose of improving the strength properties of the material.
In addition, 27SiMn and 25Mn are also more frequently used materials for hydraulic cylinder barrels, which improve the hot hardness and wear resistance of steel by adding some alloying elements such as Mn, Si, Cr, Mo, and Cu.27SiMn (27 Silicon-Manganese Steel Pipe) is one of the materials of seamless steel pipe; 27 represents the carbon content, and si and mn represent the steel pipe in the content of si and mn to do the limit.25Mn is an alloy structural steel with an average carbon content of 0.25%, a manganese content of about 2%, and a vanadium content of less than 1.5%.