So bcg in nickle boron or hard chrome

[pyrotechnic]

I am personally leery of chrome plating on bolts as fatigue appears to be the primary failure mechanism for that part. To my understanding chrome surfaces have cracks inherent to the plating process which would provide initiation points for fracture. The only peer reviewed paper I was able to find via a quick Google search on the subject of chrome plating and endurance limits was from 1949, it mentioned a marked reduction in endurance limits of plated specimens vs unplated ones. However, I am sure that processes have come a long ways since then so its results may not applicable.

Hopefully someone who is more knowledgeable of chrome plating and it's effects on engineering materials can chime in.

[MegademiC]

I am personally leery of chrome plating on bolts as fatigue appears to be the primary failure mechanism for that part. To my understanding chrome surfaces have cracks inherent to the plating process which would provide initiation points for fracture. The only peer reviewed paper I was able to find via a quick Google search on the subject of chrome plating and endurance limits was from 1949, it mentioned a marked reduction in endurance limits of plated specimens vs unplated ones. However, I am sure that processes have come a long ways since then so its results may not applicable.

Hopefully someone who is more knowledgeable of chrome plating and it's effects on engineering materials can chime in.

Yes, chrome has micro cracks. As to the effect on bolts, I have no clue.

However, the nib surface of markms bolt I checked out had cracks especially around the corners of the lugs and I suspect that is why it failed.

[pyrotechnic]

Yes, chrome has micro cracks. As to the effect on bolts, I have no clue.

However, the nib surface of markms bolt I checked out had cracks especially around the corners of the lugs and I suspect that is why it failed.

I'd like to clarify, my skepticism of chrome plated bolts was not intended to be an endorsement of the NiB coating.

[ABNAK]

I am personally leery of chrome plating on bolts as fatigue appears to be the primary failure mechanism for that part. To my understanding chrome surfaces have cracks inherent to the plating process which would provide initiation points for fracture. The only peer reviewed paper I was able to find via a quick Google search on the subject of chrome plating and endurance limits was from 1949, it mentioned a marked reduction in endurance limits of plated specimens vs unplated ones. However, I am sure that processes have come a long ways since then so its results may not applicable.

Hopefully someone who is more knowledgeable of chrome plating and it's effects on engineering materials can chime in.

While certainly not nearly on the same engineering plane as Tom12.7, I can relate my conversation with Chris Peters of Metaloy (where I've sent all my bolts for hard chroming). Before I sent my first one I spoke to him at length about the "hydrogen embrittlement" issue which I believe you are alluding to. It's been a few years and the exact details elude me but Chris kind of politely bristled when I mentioned hydrogen embrittlement. He basically said that anyone chroming today who knew what the hell they were doing would not run into that issue, i.e. it *should* be a given with today's technology and processes that HE is a non-issue. It involves a certain window of time between cooling and plating (or something like that; like I said it's been a few years).

Something chromed during the 1950's or 1960's? Might have issues. Something done > 2000? Worry not if they're worth their salt.

[MegademiC]

While certainly not nearly on the same engineering plane as Tom12.7, I can relate my conversation with Chris Peters of Metaloy (where I've sent all my bolts for hard chroming). Before I sent my first one I spoke to him at length about the "hydrogen embrittlement" issue which I believe you are alluding to. It's been a few years and the exact details elude me but Chris kind of politely bristled when I mentioned hydrogen embrittlement. He basically said that anyone chroming today who knew what the hell they were doing would not run into that issue, i.e. it *should* be a given with today's technology and processes that HE is a non-issue. It involves a certain window of time between cooling and plating (or something like that; like I said it's been a few years).

Something chromed during the 1950's or 1960's? Might have issues. Something done > 2000? Worry not if they're worth their salt.

Hydrogen embrittlement is easy to avoid, but you still see it occasionally. Like any other process, things happen. Guys in their garage can successfully plate stuff, and you have "reputable" vendors putting out stuff that flakes (flaking = complete failure)

Point is, buy good parts from vetted sources and you shouldn't have an issue. It's all process control and quality assurance.