What materials are generally used for hydraulic cylinders
The hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and makes linear reciprocating motion (or swing motion). It is simple in structure and reliable in operation. When it is used to realize reciprocating motion, the reducer can be avoided, there is no transmission clearance, and the motion is stable, so it is widely used in various mechanical hydraulic systems.
Output force of the hydraulic cylinder is proportional to effective area of the piston and pressure difference on both sides; The hydraulic cylinder is basically composed of cylinder barrel and cylinder head, piston and piston rod, sealing device, buffer device and exhaust device. The buffer device and exhaust device depend on the specific application, and other devices are indispensable.
What material is used for hydraulic cylinder:
1. Cylinder barrel
The common materials are 20, 35 and 45 # seamless steel pipes, which are honed or rolled to 0.4 μ Roughness requirements within m. 20 # steel pipe can be used for low pressure oil cylinder, and 45 # steel pipe can be used for high pressure oil cylinder.
2. Piston rod
There are two types of piston rod: solid rod and hollow rod. One end of the hollow piston rod needs to have a vent hole for welding and heat treatment. The solid piston rod is made of 35 and 45 steel, and the hollow piston rod is made of 35 and 45 seamless steel tubes. After rough machining, the piston rod is quenched and tempered to India, which is 229~285HB. If necessary, it is quenched by high-frequency quenching, and the hardness reaches 45~55HRC.
3. Cylinder head
Castings for low pressure, HT300 gray iron for medium and low pressure, and No. 35 and 45 steel for medium and high pressure. When the cylinder head itself is the guide sleeve of the piston rod, the cylinder head should preferably be cast iron. At the same time, brass, bronze or other wear-resistant materials shall be fused on the guide surface. If the structure of pressing the guide sleeve into the cylinder head is adopted, the guide sleeve shall be wear-resistant cast iron, bronze or brass.
4. Piston
Common materials are wear-resistant cast iron, gray cast iron (HT300, HT350), steel and aluminum alloy. The coaxiality tolerance of piston and piston rod shall be 0.03mm.
There are various structural forms of hydraulic cylinders, and their classification methods are also various:
1. According to the motion mode, it can be divided into linear reciprocating motion type and rotary swing type;
2. According to the action of hydraulic pressure, it can be divided into single action type and double action type;
3. According to the structure, it can be divided into piston type, plunger type, multi-stage telescopic sleeve type, gear rack type, etc;
4. According to the installation form, it can be divided into pull rod, ear ring, foot, hinge shaft, etc;
5. According to the pressure grade, it can be divided into 16Mpa, 25Mpa, 31.5Mpa, etc.