When the specific pressure in service is very high or there is a risk to damage the chromium plated surface by shocks or abrasions, it is advisable to use the induction hardened chrome plated bar. In this case the chromium overlay receives a better support by the hardened base material and is, therefore, less delicate.
For the piston rod of a hydraulic cylinder, a hardness of 54-55 HRC (HV 577-613) for the surface lying under the chromium overlay is enough. These hardness values are reachable with steel grades like UNI C43 or DIN Ck45.
In case of very high specific pressure as the one met with ball bearing systems like Ball Bushing, it is necessary that the hardness reaches 60 HRC (HV 697). In this case a steel grade like SAE4140, which gives HV 700-750, has to be chosen. For rods subjected to high mechanical stresses and for which the impact strength is important, the quenched and tempered steel grade 42CrMo4 (SAE 4140) induction hardened, is requested.
4140 induction hardened chrome plated bar usually used in Hydraulic cylinder , shock absorber, hydraulic pneumatic, textile machinery, textile printing and dyeing, engineering machinery, packaging machinery, printing machinery guide rod, die-casting machine, injection molding machine guide plunger and four-column press guide post, fax machines, printers, optic, straight axis woodworking machinery and other modern office guide shaft and some other products such as precision slender shaft for the parts industry