Materials of Hydraulic Cylinders

As an important component, the hydraulic cylinder has some material requirements. The materials must meet relevant technical specifications.

1. The barrel of hydraulic cylinders.

The processing quality of the barrel directly affects the life and reliability of the entire product. The cylinder has high processing requirements, and its inner surface roughness is required to be Ra0.4 ~ 0.8um, and the requirements for coaxiality and wear resistance are strict. Generally, it is processed and produced by the principle of honing or rolling.

The common materials of hydraulic cylinder barrels are 20# (SAE1020), 45#(SAE1045), 35# (SAE 1035) seamless honed tubes, the steel tube is honed or rolled to meet the roughness requirement within 0.4μm. The low-pressure oil cylinder can use 20# (1020) steel pipe, and the high-pressure oil cylinder can use 45# (1045) steel pipe.

2. The rod of the hydraulic cylinder

45# hard chrome plated rod (CK45 hard chrome plated rod) is also called CK45 chrome rod or CK45 chrome bar for short sometimes, it is made of 45# (SAE 1045). It is widely used as hydraulic piston rod, it is also called CK45 hydraulic piston rod.

CK45 chrome plated bar is a medium tensile carbon steel CK45 supplied in the cold drawn or turned, precision ground, polished, chrome plated and final polished condition. The tensile strength of CK45 steel is 670 – 800 Mpa, and yield strength around 520 Mpa (75Ksi). The chromed surface roughness is required to be Ra0.2.

Steel grade CK45 is equivalent to SAE standard grade of SAE 1045, so this product is also known as 45# chrome plated bar. Here below is the chemical composition and mechanical properties of CK45.

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