Chrome Plating Stainless Steel

A. Hi, Randy.

Your question is a bit abstract because you could be referring to the flash chrome which has been put on stainless automobile trim, or the hard-chrome plating of stainless steel, or conventional decorative nickel-chrome plating on stainless. The latter is probably the most common.

You generally don't see literature on this specifically; rather you see literature on how to start the process of plating onto stainless up through a Wood's nickel strike and, separately, you see literature on the process of nickel-chrome plating. If you divide it up that way you'll probably find more than you have time to read :-)

Good luck!

A. I think you mean type 416 stainless steel rather than type 316 austenitic stainless.

Type 416R is the most common "stainless" steel used for rifle barrels, no so much because of enhanced resistance to corrosion, but because the sulfur in it (thus the "R") makes it easier to machine than the traditional 4130 or 4140 low alloy steels which are also commonly used for making gun barrels.

A. Hi, Rodger. The bores of large caliber guns, such as naval guns, have been hard chrome plated for 60 years. So any challenges you encounter will involve methods and sizes rather than concept, chemistry, or performance. Best of luck.

A. Hi Ken. We appended your question to a previous, almost identical, thread.

Is this chrome plating a very thin anti-tarnish treatment for stainless steel, or are you talking about hard chrome plating of stainless steel? When you say "directly", presumably you are implying that the usual Wood's Nickel Strike is not acceptable to your client?

It's very hard to find, but if you are consulting on hard chrome plating, you might try to find a copy of Guffie's "Hard Chromium Plating", which offers ideas on this. Good luck..

Regards,

A. The "l" makes the plating a lot tougher, since not much will stick to lead. Using a fluoride based acid etch should allow you to get decent plating with A woods nickel strike followed immediately by the chrome (with rinses).
It does need watching or it might etch the parts if chemistry/temperatures and time are not maintained.

The next worry is if you are polishing it, the parts need to pass a water break test after the alkaline cleaning step. Some polishes and polisher can burn organic material into the surface of the base metal and the plate will also peel from this.

A. T304 can be polished mirror bright and has good corrosion resistance. Why nickel-chrome plate it at all? You'll accomplish almost nothing in terms of appearance or corrosion resistance.

Stainless auto trim is sometimes given a Chrome flash after buffing. It's a simple process involving electrocleaning, proprietary activator, a few minutes of chrome plating.

A. Uhhhh, James: The L in 304L means low carbon, not leaded.

But you already knew that.

Darn that Shakkour and his distracting Beach Boys note!

I think it did the same to Jim as to me. Knocked my brain half out of gear, so when I returned to the question, I saw "Cu-Ni-Cr on brass surface" :-)

Regards,

A. Unfortunately, you are correct. Even more unfortunate is that I had completely forgotten it when I answered.

So now the answer is proper cleaning, proper activation/etch and probably a woods nickel strike, then plate.