Guangxi manufactures a variety of chrome plated bar for hydraulic cylinder piston rods using high-quality carbon steel, such as 1045 steel and 4140 steel. For applications involving corrosive gases, stainless steel is used instead. The material of the piston rod requires surface quenching treatment to enhance its hardness, wear resistance, and corrosion resistance, with a quenching depth of 0.51mm and a hardness range of HRC5060. Following this, the surface is chrome plated with a thickness of 0.03~0.05mm.
The chrome plated rods for hydraulic cylinders have specific requirements, such as a dimensional tolerance of mostly f7, with some using f8 and f9, and a straightness tolerance of ≤0.02/100mm. The geometric accuracy error, including roundness, is generally not more than half of the outer diameter tolerance. The tolerance of the coaxiality between the journal and the outer circle, matched with the inner hole of the piston, should not be greater than 0.010.02mm. Additionally, the tolerance of the perpendicularity between the shaft shoulder of the installed piston and the axis of the piston rod should not be greater than 0.04/100mm. The coaxiality tolerance of the keyway, thread, and buffer plunger at the end of the cylinder piston rod and the rod diameter should not be more than 0.01-0.02mm. The buffer plunger uses the end of the piston rod itself. The surface roughness is generally Ra0.2～0.4μm, and for high precision applications, it is taken as Ra≤0.1～0.2μm.