Introduction of Hard Chrome Plated Rod 

1. Core feature: Collaborative optimization of hardness, wear resistance, and corrosion resistance
Surface hardness and wear resistance
The hardness of the hard chrome plated layer can reach 900-1200HV (approximately equivalent to HRC65-72), far exceeding that of ordinary steel (HRC20-30). For example, after chrome plating the piston rod of a hydraulic cylinder in construction machinery, there is still no significant wear after continuous operation for 5000 hours in a dusty environment, while the wear of the uncolored rod exceeds 0.5mm. Its wear resistance is due to the high hardness of the coating and the dense network crack structure (crack density of 800-2000/cm), which can store lubricating oil to reduce friction and prevent the penetration of corrosive media.
Corrosion resistance
The chrome plating layer has excellent stability in humid atmosphere, alkaline solution and organic acid, and can withstand neutral salt spray test for more than 500 hours without corrosion. In marine environments, the corrosion rate of chrome plated piston rods is reduced by over 90% compared to untreated parts. Special processes such as crack free chrome plating can further increase the salt spray resistance time to 750 hours, meeting the needs of high-end equipment.
Low friction coefficient
The surface of the chrome plating layer is smooth (Ra ≤ 0.2 μ m), and with the use of special lubricating grease, the friction coefficient can be as low as 0.05. For example, in the sorting system cylinder, chrome plated piston rods increase the operating frequency by 20% and reduce energy consumption by 15%.
2. Key selection points: Balance between materials, processes, and costs
Base material selection carbon steel: 45 # steel is economical and suitable for general loads;
Alloy steel: 42CrMo4 has a yield strength of 900MPa, suitable for heavy-duty scenarios;
Stainless steel: 316L resistant to chloride ion corrosion, used in coastal or chemical environments.
Process combination of quenching and tempering+chrome plating: Firstly, the substrate strength (HRC28-32) is improved by quenching and high-temperature tempering, and then the surface properties are enhanced by chrome plating, resulting in a 5-fold increase in overall service life;
Rolling+chrome plating: Rolling forms a cold work hardening layer (hardness HRC45-50), then chrome plating increases wear resistance by 8 times.
Cost optimization with partial chrome plating: Only the 200mm length of the piston rod in contact with the seal is chrome plated, reducing costs by 40%;
Composite coating: First nickel plating (thickness 0.005mm) and then chrome plating, the bonding strength is increased by 30%, and the nickel layer can fill the micro defects of the substrate.