For 4140 cylinder rods, leading hydraulic cylinder manufacturer Wuxi YUTONG recommends chrome hardness of at least 900 HV/10. However, there are other factors that go into the hard chrome plating process to ensure it is suitable for the proper operation and performance of your hydraulic cylinder.
Shiny surface layer of your hydraulic cylinder rod is all that stands between you and failure. This very hard, perfectly finished surface must conform to very precise specifications to preserve the integrity of the hydraulic seal and give it a frictionless surface upon which it can run smoothly.The two most common types of chrome shafting used to make hydraulic cylinder rods are CPO and IHCP. CPO stands for Chrome Plated Only, and IHCP stands for Induction Hardened & Chrome Plated. CPO shafting is typically 1045 steel with a Rockwell hardness of Rc15/19. IHCP is also 1045 steel, but achieves a surface hardness of Rc58/60 through the induction hardening process. It should be noted that induction hardening only effects the surface, with a minimum depth of .050”.Hydraulic cylinder piston Rods should have a plating coating of at between 20-30 microns.