Hard Chrome FAQs

Hard Chrome FAQs

Masked ready for plating.

 Thu 09 Mar 2017 by Admin

These are some of the most frequently asked questions regarding our processes. 

Hard Chrome FAQs.

What is Hard Chrome?

Hard Chrome, also known as Engineering Chrome or Functional Chrome, is a deposit of the chemical element Chromium with the symbol Cr and atomic number 24.  It is a steely-grey, lustrous, hard metal which can be ground and highly polished, resists tarnishing, has a high melting point and exhibits wear resistance and anti-friction properties when applied to metal components.

Where is it typically used?

Hydraulics, Aerospace and Defence, Steel Manufacturing, Automotive, General Engineering, Printing Equipment, Textile Manufacturing, Pumping Equipment, Catering Equipment etc.  The list goes on and new uses are being found continuously.

Is it toxic, what about the environment?

The final deposit of Chromium is inert and completely free of any toxicity.  The process of deposition utilises some hazardous chemicals but these are strictly controlled by European and domestic agencies who ensure that environmental best practice is followed.  Along with our accreditation to ISO 14001 we can demonstrate our commitment to the environment and ensure the world that Hard Chrome Plating is safe, clean and the only long term solution to some of engineerings most demanding applications.

How is it deposited?

Usually by electro-deposition, in a tank containing a Hexavalent Chromium Trioxide solution.  The part is immersed in the solution and a DC current applied for a set amount of time.  This can vary depending on the desired final thickness. 

How thick will the deposit be?

Starting from around 2 microns (0.002mm or 0.00008”) up to 1mm thick in some cases.  However this will depend on the specification of the part.  Typically new items will receive 25 to 100 microns thick whilst refurbished items will require much thicker deposits to bring them back to original size.

Will the coating be even?

As the coating increases in thickness so will the unevenness of the deposit.  Usually anything over 50 microns will need some mechanical finishing in order to achieve drawing tolerances and even-out the surface finish.

Can I machine it?

It is not advisable to turn or mill deposits of Chromium.  It fractures rather than cuts freely so Grinding or Polishing after deposition remain the only practical methods.

Who can deposit it and who can grind it?

Neville Roe Industries Ltd.  Please contact us for further information.