Hydrogen Embrittlement from the "horses mouth"

[Greg L.]

This may be of use to some so I thought I'd share it.

I contacted the Caswell tech line about the effects of hydrogen embrittlement with their kits yesterday. I made it clear that my concern was for my high strength suspension, steering and braking fasteners and this was thier reply.

"If you plated the parts according to the instructions for 20 minutes there should be no problem with embrittlement. When you are applying a very heavy plate you may need to bake at 375 [degrees] F for three hours. With our kits the parts will normally gas out over night.
Craige Brooks
Caswell Inc
7696 Route 31, Lyons NY 14489 USA

http://www.caswellplating.com

P: 315 946 1213
F: 315 946 4456

Ticket Details
Ticket ID: DRL-300231
Department: Tech Support (After Sales)
Priority: Critical
Status: Closed"

I've been reading a lot about this lately and read that cyanide based plating solutions have a 95% greater chance of causing hydrogen embrittlement than non cyanide based solutions which is what the Caswell solution is. I would tend to think that in this day and age of sueing over stupid things like burning yourself because Macdonalds coffee is too hot that Caswell would have thier butts covered on something as critical as this.

With them not having any warnings or a proceedure about hydrogen embrittlement then either they do feel it is an non issue with their kits or a big oversight on thier part.

The unfortunate thing for me is that most of my suspension fasteners were done commercialy before I bought my Caswell kit so I'll have to check and see if they did a post plate bake on them...

[William C.]

Re: Hydrogen Embrittlement from the "horses mouth"

Almost all commercial platers today are using non-cyanide based solutions, were I worked we changed over starting in the early 70's.

[Mike McKown]

Re: Hydrogen Embrittlement from the "horses mouth"

I think I read somewhere the parts will gas out to atmosphere at room temp over time.

[David S.]

Re: Hydrogen Embrittlement from the "horses mouth"

I really recommend baking high strength critical application components after cadmium plating. If you read the cadmium plating specifications (Military, Federal, AMS, ASTM, etc.) they all require baking after plating high strength parts. Low strength parts, although still impacted by hydrogen embrittlement, are much more ductile and therefore usually do not manifest themselves to catastropic failures. Refurbished, high strength parts have an added heightened level of concern since there may be microscopic fatigue cracking due to cyclic stresses and intergranular corrosion due to road and atmospheric salts/acid.

[Phil P.]

Re: Hydrogen Embrittlement from the "horses mouth"

if springs are not heat treated after the process ??? they will break (fail) and a small shank bolt under torque load will pop off like a 22 round---lived this problem---my 2 cents

[John H.]

Re: Hydrogen Embrittlement from the "horses mouth"

Even small zinc-plated bolts under relatively low stress will fail if not post-plating baked. I've been through two assembly plant shutdowns and stop-ship exercises caused by the vendor of self-tapping gas/brake line clip screws failing to post-bake those screws, and the heads started popping off like .22 rifle shots less than 30 minutes after being installed. Had to contain everything on the property (including the shipper's yard) and change ALL the clip bolts on every unit. HUGE PITA. Subsequent investigation at the vendor disclosed that an inadequately-trained new-hire moved several loads of freshly-plated bolts directly to shipping, bypassing the bake process. It can happen.