Application Spotlight: Hard Chrome Replacement
For decades, hard chrome plating has been used in a broad range of general industrial applications. They are chosen for their reasonably low cost, relatively easy application as well as moderate corrosion resistance and hardness. If dimensional tolerances were needed to be restored, hard chrome plating was chosen too.
However, the process uses chromium in the hexavalent state – a known carcinogen! As a result, the Occupational Health and Safety Administration has established significantly reduce exposure limits for hex-Cr in a workplace. The Environmental Protection Agency has also issued stringent air emission standards. Let’s find out how hard chrome replacement came into the picture.
Understanding the Limitations of Hard Chrome Plating
There is a need for hard chrome replacement because hard chrome has limitations. Chrome has limited corrosion resistance and hardness, which can cause problems in a wide range of applications. If chrome is not properly applied, it can also suffer from spalling, pitting and other failures if it is subject to high-stress conditions. Chrome plating can also create uneven coatings – thinner on recessed areas and thicker on the corners and edges. These problems can be rectified but at the cost of a follow-up machining step.
Another limitation of hard chrome plating is its relatively slow rate of deposition. This is a pretty serious drawback as parts used in demanding applications need to be plated up to four times to obtain an adequately thick hard coating. While no longer in use, you should note that the (past) chromium-6 has been classified as a carcinogen that poses serious environmental and occupational hazards. As chromium regulations became increasingly tightened, more manufacturers began seeking alternatives that can offer superior performance without harming the environment.
HVOF as an Alternative to Hard Chrome Replacement
At A&A Coatings, we provide hard chrome replacement coatings. We have the capability to apply tungsten carbide coatings via the High Velocity Oxygen Fuel (HVOF) process. This is one of our solutions for hard chrome replacement, and they can be used for hydraulic cylinder rods too! When you opt for our HVOF applied coatings, you can be sure of their superiority to hard chrome, possessing excellent corrosion and wear resistance.
The Benefits of HVOF
Below is a further look at the many benefits that HVOF provide:
- Heat treatment is not required
- Improved component toughness as no acid solutions involved. E.g. no hydrogen embrittlement
- There won’t be a need to maintain plating tanks
- No toxic solutions to dispose of
- Improved fatigue behavior due to coating’s ability to impart compressive stresses on the substrate
- Dense coatings that are not prone to crack crazing
- No need for water treatment plants
- No limitations on component size
At A&A Coatings, our HVOF coatings also enable microporosity that assists in the retention of lubricating films. With advanced process controls, we are also able to develop coatings that are environmentally friendly. This means no hexavalent chrome!
If you wish to know how A&A Coatings applies its expertise and experience in the field of hard chrome replacement applications, don’t hesitate to contact us today.
