Industrial Hard Chrome Plating, Electropolishing or Passivation?

Your desired end result will be the determining factor in choosing which process to select, Hard Chrome Plating or Electropolishing or Passivation.

Industrial Hard Chrome Plating brings a wide variety of characteristics and beneficial properties. This electrolytic process utilizes a chromic acid-based electrolyte bath that is activated via DC current to build chromium metal on the surface of the immersed part. The resultant Hard Chrome Plating, also known as “engineering” or “functional” chromium, is one of the most durable, wear-resistant surface finishes for the machinery industry and is applicable to interior as well as exterior surfaces.

Hard Chrome is harder than most industrial abrasives. It provides superb substrate adhesion, can be applied to a wide variety of substrates, and offers high abrasion resistance. It offers high metal-to-metal sliding wear resistance, produces a low co-efficient of friction, is stable and non-corrodible, and can provide a variety of finishes from a mirror type finish to a rough matte type finish.

If the appearance and esthetics of the piece are important then Electropolishing is the definitive choice.  If simple oxidation prevention is your desire, then Passivation would best serve your needs.

Electropolishing produces a “clean, bright, cosmetically attractive” finish by electrochemically removing a microscopic amount of material.  The end result is a unidirectional pattern that is stress-free, microscopically smooth and often highly reflective.  Improved surface finishes reduce opportunities for bacterial growth due to the removal of hydrogen leaving a chromium-rich, passive surface free of embedded contaminants and work-induced stresses.  Electropolishing typically is used for final processing rather than a technique to improve badly roughened finishes.

Passivation while serving to remove free iron remaining on the surfaces of stainless steel parts thereby making them passive to oxidation, does not provide the surface improvement qualities that Electropolishing provides.

Hard Chrome Roll

Hard Chrome Plating, also known as “engineering” or “functional” chromium, is one of the most durable, wear-resistant surface finishes for the machinery industry. It is applicable to interior as well as exterior surfaces.


ACME is proud to announce the establishment of a newly expanded Electropolishing department. The new system has also increased capacity and reduced our turnaround time for handling of production orders.


Passivation, is a commonly required process for products manufactured for the medical, electronics, aerospace, and food processing industries. Sometimes referred to as “Stainless Steel Pickling,”

Extended Services

In addition to meeting your Industrial Hard Chrome, Electropolishing and Passivation needs, we also provide our customers with a variety of customized extended services.

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Cylindrical or O.D. grinding is typically used to produce very accurate dimensional sizing before as well as after hard chrome plating.  Tolerances of (+) or (-) 0.0002” can be consistently held.  Grinding also is used to improve the surface finish after machining cylindrical components.  Surface finishes can vary from 64 Ra to as fine as 2-3 Ra.


Polishing a part after grinding serves to further improve the surface finish by removing grinding lines, scratches, or surface defects that affect the appearance of function of a component.  Polishing is typically used before and after hard chrome plating.


Honing is a process that uses abrasive components to produce precision sizes and surfaces on internal diameters.  A part is typically honed after machining and prior to hard chrome plating.  In some cases honing is also required after internal diameters have been hard chrome plated.  Honing will improve the finished surface as well as providing very accurate dimensional sizes.


Straightening is a process that restores metal parts to their original specifications after being distorted through repeated use.  Straightening is typically performed prior to grinding and polishing in preparation for hard chrome plating.


Welding repair is used quite extensively at ACME to salvage and recondition parts that have been damaged during use.  TIG or MIG welding is provided as part of ACME’s ongoing services to our customers.


ACME provides two types of surface profiling.  One type of surface profiling is to measure a surface’s profile through precision instrumentation to quantify its roughness.  In many cases specific surface conditions must be provided prior to hard chrome plating.

The second type of surface profiling is by changing the surface conditions of a particular part by mechanical means.  Usually media blasting is used to obtain various finishes required by the client.  The varieties of profiles range from extremely rough to nearly mirror reflective finishes.