Selection requirements for hydraulic cylinder materials of hydraulic presses

The hydraulic cylinder is an important actuator component in the hydraulic system of the hydraulic press, so the selection of its materials and pressure resistance requirements must comply with relevant technical specifications and standards. The specific cylinder material should follow the following aspects:

1. Under normal circumstances, it must have sufficient strength and impact toughness, and it must have good welding ability for welded cylinder barrels. According to the parameters, purpose and blank source of the hydraulic cylinder, the following materials can be selected: 25 steel, 35 steel, 45 steel, etc.

2. The cylinder barrel blank generally uses annealed cold-drawn or hot-rolled seamless steel pipes. At present, there are seamless steel pipes in the domestic market that only need to be cut to the required length after honing or finishing of the inner hole. The materials are 20 steel, 35 steel, and 45 steel.

3. For hydraulic cylinder barrels with an operating temperature below -50℃, 35 steel and 45 steel must be used, and they must be tempered.

4. For cylinder barrels welded to the cylinder head, 35 steel is used, and it is tempered after machining; for cylinder barrels not welded to other parts, 45 steel with jump quality is used.

5. The blank of the rear wall is still made of cast iron or forgings, or rolled into a cylindrical shape with rear steel plates. After welding, it is annealed and the weld needs to be inspected by x-ray or magnetic flaw detection.

The pressure resistance of the cylinder is also very important. It must have sufficient strength to withstand the short-term dynamic test pressure of a specific working press for a long time without long-term deformation. At the same time, it is required to have sufficient rigidity to withstand the lateral force of the piston and the reaction force of the installation without bending. The following two aspects should also be noted:

1. The inner surface of the cylinder and the piston rod seal and guide ring can work for a long time with less wear under the action of friction, and the dimensional tolerance grade and shape and position tolerance grade are sufficient to ensure the sealing of the piston seal.

2. The cylinder that needs to be welded must also have good weldability so that cracks or excessive deformation will not occur after welding the flange or pipe joint.