Max. Hard chrome plating Thickness
A discussion started in 32006 & continuing through 2017
Q. I would like to know from experts the following:
1) Can we deposit chrome plating up to 0.75 mm thick on the hardened bushes, to increase the Dia by 1.5 mm. (166,5 to 168mm)?
2) The bushes with increased dia. are to be fitted using Liquid Nitrogen. Will chrome plating be affected by Liquid nitrogen? Will it get peeled off?
Will appreciate if some one can answer urgently.
- Mumbai, India
A. Theoretically yes, but hard chrome is too brittle (less than 1%) compared to 15% or more for steel and may spall or chip. For that thickness it will also be cracked. The cracks may be thin and shallow but, depending on process parameters, they may penetrate into the base material allowing for corrosion products to undermine it. Nickel (particularly from a sulfamate bath) can be deposited to that thickness and even more. Its elongation matches that of steel. Other options: thermospray (less adhesion), press fit of another bushing.Guillermo Marrufo
Monterrey, NL, Mexico
A. Guillermo is right. Most aircraft repairs usually call out a chrome thickness between .003-.005 inches (.076-.127 mm). Once chrome gets thicker than this the part starts to take on the metallurgical properties of chrome rather than the base metal. Nickel plate and grind to a thickness that will allow a subsequent chrome plate and grind to the final dimension leaving the .003-.005 inches of chrome.Tim Hamlett
Decorative Plating - Miami, Florida, USA
November 17, 2017
Q. My spindle shaft needs 0.05 mm chrome plate thickness. The shaft size went down and now it needs 0.127 mm thickness of chrome plating. Is there pa ossibility of peel-off in later stage?Balaji Somangilee Balan
Larsen & Toubro Ltd - Chennai, Tamilnadu, India
November 22, 2017
A. Usually, it is not a problem to have 50-150 microns (0.002"-0.006") of hard engineering Chrome per side on a round part. To prevent peeling, surface has to be properly activated (depends on base material: for regular carbon steel or low alloy steel - reverse etch in Cr plating solution). It's recommended to plate a little over required size and grind the deposit to size. Also Hydrogen embrittlement relief bake is critical immediately after the plating.Leon Gusak
- Winnipeg, Canada
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