Baking new chrome plate?

OK, awhile back I started a thread looking for a guy, reputed to be somewhere around Newnan, GA who had a plating shop and a hookup with a shop in Alabama too, allowing them to take advantage of differing environmental laws in 2 adjacent states.
Well I found the guy and talked on phone to him yesterday. He related that yes,he could and did do triple chrome plating, copper, nickel, then chrome. Bring it over and he'd take a looksee and price it. Fair enough, but cautious as I am, I asked him about baking the finished job, as this is Curtiss type wishbones, Batwings, and Panhard bar bracket. He sort of shrugged if off and said when he took it out of the plating tank and cleaned it up, it was finished, didn't really confirm or deny understanding the concept of baking new chrome plate when it's on suspension parts in order to avoid hydrogen embrittlement with a potential to cause cracks.
In reading all the hot rod mags and related, since around 1950 and also a career as a machinist in an airline engine repair shop where hard chrome was routinely used in buildup for repair of parts in a plating shop right across the hall from us, and reading the routings tags on previous operations in the repair process, I always had been told, if it's stressed and you chrome it, you gotta bake it.
Now this guy says he's been in the plating business for 37 years, never baked a part he plated, and never had a part break he had plated. Says he's sent 3 kids thru college with income from his work, but no baking new chrome.
So, I'm running this thru my head and I remember my last trip down to Moultrie, GA swap meet last Feb., where I talked with a guy from Advance Plating at their display area.
I asked him about baking vs possible hydrogen embrittlement, and he replied that there was a new process that no longer needed baking, but they were equipped to bake if I put it in work order.
So now I'm wondering if my knowledge of past technology has been obseleted by new technology?
Any body have knowledge in this area?
Dave

 

I remember the Official HAMB Metalurgist posting that Hydrogen Embrittlement was only a problem on parts over a certain Rockwell number.AND,the parts had to be baked within a few hours of plating.

If he doesn't magically appear,send a PM to 38Chevy454.

 

The way I understand it, the electrolysis process lines up the random molecules causing it to become brittle. I know the aerospace folks have to be weary of it but the only automotive warnings I have heard of was about plated hood springs needing it.

 

I had a windshield frame split open to the point of destruction on my 35 Ply. I also saw a fellow Lssra members rear end spilt at a rod run we both attended. Niether of these items has a high rockwell number. Chrome is for show,never use it on anything critical. Powder coat etc.OK. Baking properly makes chrome lose its pretty lustre.

 

http://www.jalopyjournal.com/forum/showpost.php?p=1084635&postcount=7

If your parts are Mild Steel,you should be OK.

 

I get stuff plated at work. Mainly ferrules for hoses. They are made from 1020 ~ a very soft steel. Trying to find a plater at all here is difficult, let alone a good one. Anyway, I reject about half of the batches from the platers because they crack.
Embrittlement CAN happen in soft steels!

And yes, the baking needs to be done very soon after plating.

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

 

HE is very hard to cause problems if the steel is not hard enough. Your "soft" steel is probably work hardened due to forming and is not in fact "soft" anymore. But I will not argue, your results show that you have cracking of some type.

BTW, any plating operation cause hydrogen to be produced at the metal surface of any hardness metal, some of the hydrogen gets diffused into the metal. But it is only a problem if the steel is susceptible, which is generally considered to be ones that are above Rockwell C 30. However any plated part has hydrogen increase due to plating, it just does not cause cracking.

Also HE is a problem with parts that are under sustained stress loading. Not for small time period loads. A part with real bad HE will crack and fail within 8 hours or less. The typical test for HE is to stress the part to 90% of yield and hiold for 72 hours. Any failure out of the sample lot (say for dicussion 10 pieces) would reject the entire lot. A part with HE that is not under sustained load will not fail by HE.

A plated part that fails after many years is not from HE, but would be most likely from fatigue cracking. People always see a failed plated part and then blame HE as the cause, even though the part was in service for 5-20 years or more. This is not HE, remember above that HE will fail quickly under sustained stress.

You can bake any plated part, no matter what condition the steel is on. Sooner the better right after exiting the plating bath is best. Post bake polish will bring it right back to shiny, the oxidation is minimal.

 

i agree! anything more critical than a cup-holder needs post-plate baking after any form of electroplating

 

I WORKED AS A PROTOTYPE MACHINIST IN AN AEROSPACE LANDING GEAR SHOP THAT USED PLATING YOU NEED TO FOLLOW THE MIL.SPEC. ON HEAT TREATED STRESSED PART. IF YOU ARE WORRIED ABOUT YOUR PARTS BEING HARD IN THE WELD AREAS, HAVE THEM STRESS RELIVED OR NORMALIZED BEFORE PLATING.

ALSO, I RECALL A TEST BEING DONE ON A/C PARTS TO VERIFY THE MIL. SPEC. THE FIRST SAMPLE WAS DONE BY THE BOOK. THE OTHER VIOLATED ALL THE RULES AND SPECS. EVERY EFFORT WAS MADE TO ENHANCE "WORST CASE SCENARIO". BOTH FAILED WITHIN 1% OF EACH OTHER. THE FIRST SAMPLE CAME IN SECOND PLACE. FOLLOW THE BOOK WHEN YOUR REAR IS HANGING IN THE BALANCE. HAVE FUN!

 

If it's suspension, steering parts I'd err to the safe side and insist on baking-even if that means shipping the parts out. As acomparison; I'm a decent weldor but if it's steering components, I take the parts over to a certified aircraft weldor and pay him for welding.

IIRC, the HR article in Streeet Rodder had photos of a chromeplated front axle that was snapped. Sure, we don't know if it was the plating process or simply the axle itself, but why take a chance?

 

So, for dummys like me. Do I need to worry about my dropped Henry Ford axle or any of the forged ones like So-Cal or Chassie Engineering sells, if I have them chromed?? Do any of these companies heat treat the chromed parts they sell?

 

It also has to do with the amperage used for plating. Higher amperage speeds up the electroplating process, but contributes to the imbrittlement of the part. I worked in a propeller repair station. A lot of the hardware is cad-plated. The owner was particular, to the point of insane, about keeping the amperage below a certain value, was continually checking to make sure the potensiometer control wasn't creeping. Of course it was a manual device in those days, now I'm sure they have microcircuit controls. It's my guess in a "for purty" chrome shop they don't have to worry, use high amperage to make the process go faster.

 

In my experience, most of them don't even seem to know what Hydrogen Embrittlement is, which is why I will not buy plated suspension parts, but choose to have them polished and plated by my own platers.

As for shipping out parts, that is hardly a good idea as the embrittlement relief (bake) should be doen with a few hours of the parts coming out of the chrome tank. I pick my parts up from the plater still wet and personally take them over to the heat treatment facility - in my case Milspec Heat Treating in Huntington Beach, CA - near the Boeing Space Division. www.milspecheattreating.com