High Tensile Chain Hydrogen Embrittlement

[akio.kanemoto]

Originally Posted by craigsmith

Grade P is G50 and I've only ever seen it in stainless. Strange that they'd recommend only that for anchoring, although ideal it's hardly realistic for the bulk of customers on account of the price as you can see.


If you mean in NZ, this outfit is probably your best bet. Here's the link to the page for 8 mm Maggi Aqua7:
www.chainsropesandanchors.co.nz/shop/8mm-aqua7-hi-tensile-short-link-maggi-chain-p-596.html
Deduct the included NZ GST (12.5%) for an export order. If your vessel is foreign flagged in transit you shouldn't have to pay Australian GST either so keep on top of that.
Phone them up and check re stock and shipping before placing an order. (No affiliation)
This is the Maggi catalog if you're interested:
Catalogue - Maggi Product Guide - Maggi Group - (Version JPG) - 1

Thanks again for the pointer, alas I was hoping for a contact in Australia. I will give the guys above a call on Monday and see what they will charge for freight though... here's hoping.

Now, the funny thing today is that I tried PWB Anchor again.. and said, OK, quote me 66m of Grade P please... and lo' and behold... they only make it 10mm +... unless it's a special order.

Since I'm desperate, I asked what is the minimum quantity for a special order... she went away and came back and said "340m... BUT we won't do it ... as we don't recommend it"

AARARARHGGH!!!

OK, So I'm going crazy here.

I have one final idea:

Q: Can I buy transport chain and just get it galvanized myself?

This is Grade 70 chain - is this what I'm looking for?

Secure A Load - Chain Per Meter - Tiedown

Thank you muchly in advance!

[craigsmith]

Originally Posted by akio.kanemoto

Thanks again for the pointer, alas I was hoping for a contact in Australia. I will give the guys above a call on Monday and see what they will charge for freight though... here's hoping.

It's looking like your best bet eh. They ship a lot of stuff over to Aus so ask them if they know anyone who does Maggi over there.

Originally Posted by akio.kanemoto

Now, the funny thing today is that I tried PWB Anchor again.. and said, OK, quote me 66m of Grade P please... and lo' and behold... they only make it 10mm +... unless it's a special order.

Since I'm desperate, I asked what is the minimum quantity for a special order... she went away and came back and said "340m... BUT we won't do it ... as we don't recommend it"

I don't really understand this, you want stainless? It is only a little stronger than G40, frankly you might as well stick with that, I don't see much value in stainless G50. Better to spend the money on shipping G70 from overseas.

Originally Posted by akio.kanemoto

Q: Can I buy transport chain and just get it galvanized myself?

This is Grade 70 chain - is this what I'm looking for?

Secure A Load - Chain Per Meter - Tiedown

Thank you muchly in advance!

In theory, but in practice...
That product says it is electroplated gold, so you would have to clear that off before you could hot dip galvanize it. Possibly that's not a big deal, I don't know enough to say. Then, if the steel in the chain is not intended for galvanizing, it may contain levels of phosphor or silicon that make it not ideal for HDG - not impossible to overcome but complications ensue. You will need to know the steel metallurgy to show the galvanizer.

In addition to that you have the embrittlement concerns of high tensile steel to worry about. Strain age - cold working of the links during assembly? Have they been annealed at all? Hydrogen embrittlement - can the galvanizer avoid pickling beforehand (blast instead)? - my guess is not. Or baking afterward to minimize damage. You would also be strongly advised to have the chain proof tested afterward. A lot of effort and my bet is the expense is not going to be less than shipping from offshore.

[akio.kanemoto]

Originally Posted by craigsmith

It's looking like your best bet eh. They ship a lot of stuff over to Aus so ask them if they know anyone who does Maggi over there.


I don't really understand this, you want stainless? It is only a little stronger than G40, frankly you might as well stick with that, I don't see much value in stainless G50. Better to spend the money on shipping G70 from overseas.


In theory, but in practice...
That product says it is electroplated gold, so you would have to clear that off before you could hot dip galvanize it. Possibly that's not a big deal, I don't know enough to say. Then, if the steel in the chain is not intended for galvanizing, it may contain levels of phosphor or silicon that make it not ideal for HDG - not impossible to overcome but complications ensue. You will need to know the steel metallurgy to show the galvanizer.

In addition to that you have the embrittlement concerns of high tensile steel to worry about. Strain age - cold working of the links during assembly? Have they been annealed at all? Hydrogen embrittlement - can the galvanizer avoid pickling beforehand (blast instead)? - my guess is not. Or baking afterward to minimize damage. You would also be strongly advised to have the chain proof tested afterward. A lot of effort and my bet is the expense is not going to be less than shipping from offshore.

No, I definitely don't want stainless - their Grade P recommendation is just normal galvanized as far as I'm aware.

As for the various warnings on galvanizing G70... considering that I can't even find somebody to talk to here about the chain itself - I'm thinking that finding a galvanizer who knows how to deal with high tensile chain will be even more difficult...

Well, I'll see how I go with Chains Ropes and Anchors.co.nz... at least their FAQ on shipping states that they do ship overseas.. a good start.

Thanks again, I'll post back when I hear from them!

[Adelie]

As I understand it G7 & G8 steel chain is heat treated so regalvanizing more than once or twice will lead to significant strength loss.

High Test/High Tensile/G4 however is just an alloy change from regular low carbon G3 chain so the heat of repeated galvanizing will not affect its strength.