Summary for hard chrome plating hardness Discussion
Hard chrome plating hardness is the key question in this thread, with readers asking whether chrome can reach 1000–1200 BH and what minimum steel hardness is needed underneath. The page notes that hard chrome is widely used on machine parts because it is hard, wear resistant, and low friction, and that its surface texture can help retain oil on parts like hydraulic piston rods. The editor points readers to Toby Padfield’s earlier answer on the page for the practical guidance. The discussion also reminds readers that hardness conversions between scales are only approximate. In short, the thread centers on whether hard chrome can provide very high surface hardness on steel rolls and rods, and the answer is treated as already covered elsewhere on the page rather than restated in full.
Readers may wish to start with our “Introduction to Chrome Plating” if they don’t know much about it. Hard chrome plating is frequently applied to machine parts because it is hard, wear resistant, and has a low efficient of friction. In some cases, such as on hydraulic piston rod, its miniaturized “dried mud bed” topography is important for holding oil.
[editor appended this entry to this thread which already addresses it in lieu of spawning a duplicative thread]
Q. Hi, I am Masoud, I am working at aluminum rolling company for aluminum foil production. I would like to use chrome plating on the surface roll after grinding, can iI achieve hardness up to 1000 to 1200 BH with chrome plating while hardness in our steel rolls is 66RC? Can you help me?
Masoud hasan
– Dubai, UAE
February 13, 2025
Ed. note: Yes! Toby Padfield has answered that on this page. Good luck.
Multiple threads merged: please forgive chronology errors and repetition 🙂
Q. It was mentioned in your Chrome Plating Tutorial that the hard chrome plating is usually applied to a “hardened” surface. Could you please tell me how hard the actual plating is and what the recommended min. hardness level (HRc) the steel should be to support it?
Joseph Pleichner
Design Engineer – Cleveland, Ohio, USA
2007
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Hard chromium plating: A handbook of modern practice by Greenwood (1981)
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“Hard Chromium Plating”
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“Chromium Plating”
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A. The substrate hardness is usually specified as 40 HRC minimum (390 HV minimum), but more typically ranges from 45-50 HRC (450-515 HV). Since the chromium plating is so thin (typically 15-25 micrometers) it cannot be directly tested using HRC, but it can be measured using Vickers microhardness and then converted to an approximate HRC number. Cr plating is usually a minimum of 900 HV (67 HRC), but is more typically around 1000-1100 HV. 940 HV is ~ 68 HRC which is the last data point in ASTM E140 or ISO 18265.
Toby Padfield
Automotive module supplier – Michigan
A. We commonly plated to 0.010 and you still use a Vickers or Knoop hardness. It does not exactly relate to HRC, but it is more than close enough for government work.
James Watts
– Navarre, Florida
A. Try this web-site:
www.efunda.com/units/hardness/show_hardness.cfm
Remember when converting between the various scales that each is only an approximation for the other.
Brian Terry
Aerospace – Yeovil, Somerset, UK
[editor appended this entry to this thread which already addresses it in lieu of spawning a duplicative thread]
Q. What is the actual hardness of hard chromium plated ground steel rod.
Material: CK 45 / EN8D,
Chromium Thickness: 25 micron minimum on radius
Surface Roughness: Ra MAX. 0.2 micron
Sanjeet Ojha
hydraulics – New Delhi, INDIA
July 15, 2013
Ed. note: Toby Padfield has answered that above. Good luck.