Re-galvanizing G70 anchor chain in Australia

[Carl94965]

Hi
Just reaching out to see if anyone can recommend a good place in Australia to re-galvanize my 10mm G70 Maggi anchor chain? I am currently located in Queensland.
Thanks

 

[Neeves]

Any local galvaniser can do it, International Galvanisers have a facility in or near Brisbane and there is a galvaniser at Bundaberg

The original galvanising degraded the original strength of the chain (which might have been a G100 or G120) it was re-tempered by the original galvanising. The re-tempering or degradation is factored into the original chain manufacture.

As long as any second or third galvanising is conducted at the same temperature the strength of the chain will remain the same as it is now, a G70.

All galvanisers work at the same temperature - there are no concerns.

You are, almost, good to go.

The problem is that most galvanisers will want to pickle (clean with acid) the chain. and there is a risk of Hydrogen Embrittlement. If the chain its not clean - it will not take the galvanising. The solution is to have the chain grit blasted. But oxidation commences as soon as the chain comes out of the grit blaster (time, tide and oxidation wait for no man) and you need to get the chain to the galvaniser - the same day. Lightly oil, pack in a sealed oil drum - coordinate between grit blaster and galvaniser. Get it actually galvanised the day it is grit blasted.

You need a galvaniser with a shaker or centrifuge and as the Bundaberg and IG plant both process chain - you will be in good hands.

I think Serafini use IG and PWB used to use, still use, IG in Victoria.

If you have painted marks, for length on the chain and if the chain is a bit corroded - take the chain to your nearest 'acceptable' beach and tow the chain across the beach. This will remove the paint and some of any corrosion and make the grit blasting easier and, maybe, cheaper.

Discuss all of this with both the galvaniser and grit blaster (the galvaniser might have grit blasting on site). Make sure everyone knows what you and they are doing.

I don't know people in Qld - I cannot offer much more help.

Many galvanisers don't like working with chain, especially old anchor chain - I think IG in the US have stopped doing it. You may need to use your powers of persuasion. I'd suggest you hold any discussions - face to face. When I regalvanised, I did it twice, I knew the people at one of the facilities and the others were happy to do what I wanted as long as I took the risks - and paid with a slab of beer. Many of the employees and staff own boats and will have had their own chains regalvanised - (but not G70)

I don't make these things up. I actually did as you are trying to do here, (I tested before and after) and the results, or process, was confirmed by Peerless (the biggest chain maker in the US). Peerless were offering no warranty.

Most of the internet chatter on regalvanising (and even using) G70 is just..... chatter. No-one has bothered to check reality.

Regalvanizing G70 Chain - Practical Sailor

Jonathan

Minor edit - how long has your gal lasted, estimate number of days at anchor. Making a rough check of people who collated data on their own chain 1,300 nights at anchor seems to be typical.

Also - I note you are using 10mm chain - its seriously heavy. if you are dragging across a beach you will need help.

 

[vyv_cox]

I have looked into the subject from a theoretical viewpoint but do not have Jonathan's experience with G70. Hydrogen embrittlement is generally a problem with high strength steels, which G70 is not. I doubt that it is an issue here but there may be a small risk.

 

[Neeves]

I have looked into the subject from a theoretical viewpoint but do not have Jonathan's experience with G70. Hydrogen embrittlement is generally a problem with high strength steels, which G70 is not. I doubt that it is an issue here but there may be a small risk.

I had not thought of that .

As far as I can ascertain most of the higher strength steels available for chain, like G70, are based on using an even higher strength steel G100 would just about work but maybe G120. The caution or worry of HE is possibly only restricted to the original feed stock, G100 or G120, and the original, or first galvanising, process. Once its galvanised and retempered its no long a 'HT' steel that might be susceptible to HE (as its now G70).

If you progress and I see no problems other than moving the chain about, its heavy, (and why I did all my work on 6mm chains) then make sure you get a decent galvanised coating. The process is fairly standard but coating thickness determines longevity, more coating = longer life. You cannot demand extra coating thickness, normally around 70 microns, but some galvanisers skimp. If you go over thick the coating can lose adhesion to the underlying steel and flake. Most galvanisers will have coating thickness meters - its easy to check.

If you approach the galvaniser and he is sympathetic to your needs he will know how to give you a decent coating.

If you look at Peerless galvanised G70 its not as strong as Maggi's - so Maggi are using a different feed stock. I do know Maggi were using a Rud G100 Omega link for their enlarged link - as it says so on the link. But galvanising G100 will be a bit hit and miss to achieve a G70 strength which makes me think they might be using a G120 for the chain.

If I were doing this I'd happily regalvanise but I be cautious and sample a 0.5m length from one end and have it tested for strength and then have another piece tested for strength after the regalvanising.

In America they claim to be making galvanised G120, that's to a G120 strength. The product is sold to the Marines and Navy. They are using a different galvanising process but they must be doing 'something else' to retain the strength. It could be they quench and temper - so re-make into G120 - but to do so means they know the Q&T process - which is commonly proprietary and confidential.

Gunnebo are making a galvanised G80 chain for the aquaculture industry - but their chain uses oversized wire - so 8mm + 10% so it would not fit on our gypsies. Its also a bit of a misnomer. I had thought that the Gunnebo product would be a good competitor to Maggi (Gunnebo have an excellent reputation enhanced as they are now owned by Crosby). But the chain looks to be too big for a gypsy (I have not tried it) and they don't make matching connectors (other than shackles). Crosby's, Peerless' and Campbell's better shackles are all G80). Things may have changed - I have not looked recently.

Gypsies are hardly sophisticated bits of kit, chain is no better and there might be enough wriggle room for Gunnebo's galvanised G80 to fit the appropriate gypsy. What's needed is a 1m sample and try it - but the Gennebo subsidiary here is not enthusiastic and it really needs someone in Europe (closer to the production) to try it out.

Jonathan

 

[Carl94965]

Thank you so much for the feedback. I am going to contact the galvanizers you mentioned to see if they do grit blasting. If I can't find a good solution to grit blasting, I may have the galvanizer clean the chain with the standard pickling process.

Thanks again,
Carl

 

[Neeves]

There may be other galvanisers - ask around. If you make a google search there are a number of galvanisers in QED (most I did not know exists) - but they may not be able to handle chain (possibly lacking a shaker or centrifuge).

I'm assuming the chain is in reasonable condition and not flaking rust. If you have rust flakes you are losing base metal and more importantly you have lost strength.

If your anchor needs to be re-freshed - submit it at the same time. Most galvanisers work on weight - though they may have a special rate for chain - but adding an anchor will not make much difference to the cost.

If this works out - when you get the chain back it will look really sexy (dependent on your tastes ) - all bright shiny metal. This will soon tarnish and disappear - this is normal.

Galvanising is an alloying process, you are converting Iron (Fe) and Zinc (Zn) to Fe/Zn alloys and the outer layer is pure zinc. Pure zinc is soft and shiny and soon oxidises and wears off. Galvanising, the ZnFe alloys, tend to be a matt grey colour. The new outer zinc in your chain locker also converts to 'white rust' in the damp environment - it is normal, or not abnormal.

Vyv was directly involved in hot dipped galvanising and might add from a much deeper background.

You will prolong the life of galvanised chain if, when you wash the deck, you wash the contents of the chain locker with fresh water, keep the chain locker clean and as dry as possible (though not really possible) and keep rope (which retains moisture) away from the chain. Moisture and Mud are killers - some mud is anaerobic and plays host to organisms that produce sulphur compounds that give the mud, that 'bad egg' smell, are acidic - and eat galvanising . These muds are found in slow moving rivers and stagnant water - exacerbated by high nutrient levels - some Asian bays, river mouths are, anecdotally, said to be of particular concern when anchoring nearby (but maybe also some Australian rivers).

https://www.sailmagazine.com/diy/know-how-ground-tackle

Jonathan

 

[vyv_cox]

Jonathan, do you have any compositional data on G100 and G120? According to my information G70 has the same composition as G40 but is heat treated, so 0.2% carbon, 1% manganese. If the higher grades have more carbon they exceed the 'rule' of less than 0.2%, which avoids the possibility of brittle martensite on heat treatment.

Alternatively, do they have the same composition but a lower tempering temperature? Not sure this would give the required strength.

 

[Neeves]

Vyv, No idea on composition nor on tempering temperatures. Chain makers, and anyone Q&Ting steel guard their processes closely.

My understanding of G70, specifically Peerless G70 is that it is slightly different to G43. I understood the steel for G70 has a bismuth (might have been boron) addition to the steel.

Slightly off topic but Bisalloy, the company, source their steel plate from BHP, the 2 facilities are not far apart. The steel is specially made to Bisalloy's chemical requirements and is delivered in big plates of differing thicknesses. I was shown round the Q&T process - no cameras allowed. Questions on temperature were answered with a smile.

I got on well with the, then, General Manager at Armorgalv whose background was steel making and HDG. He was very sympathetic to what I wanted to achieve and he believed that if we could quantify the Q&T processes for chain he could galvanise and then temper. More recently Spencer Inc in New Jersey who run an Armorgalv facility claim to be able to coat G120 and retain the G120 spec - which implies they have defined how to temper or re-temper. But they have big support from the US military - amateurs are lucky to get the time of day.



Jonathan

 

[vyv_cox]

Vyv, No idea on composition nor on tempering temperatures. Chain makers, and anyone Q&Ting steel guard their processes closely.

My understanding of G70, specifically Peerless G70 is that it is slightly different to G43. I understood the steel for G70 has a bismuth (might have been boron) addition to the steel.

Slightly off topic but Bisalloy, the company, source their steel plate from BHP, the 2 facilities are not far apart. The steel is specially made to Bisalloy's chemical requirements and is delivered in big plates of differing thicknesses. I was shown round the Q&T process - no cameras allowed. Questions on temperature were answered with a smile.

I got on well with the, then, General Manager at Armorgalv whose background was steel making and HDG. He was very sympathetic to what I wanted to achieve and he believed that if we could quantify the Q&T processes for chain he could galvanise and then temper. More recently Spencer Inc in New Jersey who run an Armorgalv facility claim to be able to coat G120 and retain the G120 spec - which implies they have defined how to temper or re-temper. But they have big support from the US military - amateurs are lucky to get the time of day.



Jonathan

Peerless G100 apparently uses steel to SAE 8620, which I find is similar composition to Grade 40 and 70 with additions of 0.5 Cr and Ni plus 0.2 Mo. SAE 8620 Alloy Steel | SAE 8620H-Fuhong Steel

 

[rogerthebodger]

If your chain needs grit blasting to clan it up tie it to the back of a car 4x4 and toe it along a Queensland dirt road

This will clean up the chain so the pre treatment will do the rest

Generally grit blasting is only needed it there is paint on the chain as the galvanizing pretreatment will not remove paint

 

[vyv_cox]

If your chain needs grit blasting to clan it up tie it to the back of a car 4x4 and toe it along a Queensland dirt road

This will clean up the chain so the pre treatment will do the rest

Generally grit blasting is only needed it there is paint on the chain as the galvanizing pretreatment will not remove paint

When BE Wedge still ran their chain line their procedure for painted chain was to run it through the zinc bath without the prior acid bath. This burnt off paint and other contaminants without adding any zinc. I was at their plant when they were doing this, when the smoke was so thick that it was impossible to see across the shop.

 

[MM5AHO]

A good directory of galvanizers in Australia is on the GAA (Galvanizers Association Australia) website. https://gaa.com.au/find-a-galvanizers/
This covers about 90% (some are not members).
I've been in many of the Australian galvanizers places (and I'll be back there again in Feb), and have seen chain in several of them. QLD is a big place, so could be one near the OP.
As Jon N says, all could do it, but many find it just too much bother. Some persuasion could move that position.
The idea of oiling a shotblasted chain to prevent oxidation between blasting and galvanizing won't be popular. They'd want to degrease it first, and after aqueous process, they'd need to pickle it.
At G70 H2embrittlement is very rare, almost unheard of.
By "International Galvanizers" Jon, did you mean Valmont?

 

[Neeves]

A good directory of galvanizers in Australia is on the GAA (Galvanizers Association Australia) website. Find Australian Galvanizers
This covers about 90% (some are not members).
I've been in many of the Australian galvanizers places (and I'll be back there again in Feb), and have seen chain in several of them. QLD is a big place, so could be one near the OP.
As Jon N says, all could do it, but many find it just too much bother. Some persuasion could move that position.
The idea of oiling a shotblasted chain to prevent oxidation between blasting and galvanizing won't be popular. They'd want to degrease it first, and after aqueous process, they'd need to pickle it.
At G70 H2embrittlement is very rare, almost unheard of.
By "International Galvanizers" Jon, did you mean Valmont?

Yes,

Valmont.

Most people talked of IG, rather than International Galvanisers, and I actually never heard of anyone using the name Valmont - even though many were owned by Valmont. There are lots, or more than I expected, of small galvanising operations and galvanisers hiding within other industries. Webforge, who make industrial steel walkways, galvanise in house (or did before they moved out of Sydney to Old). This is logical as steel mesh walkways are all galvanised.

All the chain, G100, we have had Armorgalv coated has been shot, or grit blasted, then lightly oiled (diesel) and shipped in sealed oil drums. The Armorgalv process involves no acid and grit blasting is part of the process. They approve of the method of preparation, grit blasting and oiling, over other options. They have said the grit blasting is a better surface to coat (and I assume the oiling reduces oxidation).

Armorgalv promote their process of being such that as there is no pickling, only grit blasting, there is no opportunity for Hydrogen Embrittlement in HT steels (but they don't define what they mean by HT steels). Much of their customer base supply HT steel components, the studs for wind generator towers are a good example.

The end product, in terms of anchor chain, is a G70 specification, or near, the feed stock is something of a higher tensile strength, at least G100 and maybe G120. The risk of HE is not with the G70 but the feed steel. Maggi has been galvanising something, G100 or G120, for years - and I have never read of a failure of their chain (only question marks, I think unfounded, of poor galvanising). The big HE failures that I know of have been with galvanised HT bolts.

When I was testing the re-galvanising of G70 chain I discussed with a local HDG operator, I think Sydney Galvanising, what I wanted and we discussed pickling. They told me that if they did not pickle, or grit blast, the chain would not galvanise. They illustrated this to me. I provided 2 pieces of the same G70 chain and they pickled one and left the other as clean steel. They then galvanised the 2 pieces together. The un-pickled chain came out clean - it simply looked scorched, dry and dusty - no coating. The pickled chain came out all bright and shiny. I tested both pieces for strength and they were both a similar tensile strength to the G70 that was the 'feedstock'.

I was impressed and convinced at the need for clean chain. It underlined why galvanisers don't like paint.

There are only 2 chain makers, of which I am aware, in Australia. PWB and Serafini (and Serafini may have closed). Anecdotally I heard that PWB had stopped making galvanised G30 anchor chain and were buying from China. PWB is now part of the Kito (of Japan) family along with Peerless and Kito Italy (that Kito rescued from the administrators). Neither PWB nor Serafini galvanised in house - it was all conducted 'outside'

Jonathan

 

[rogerthebodger]

When BE Wedge still ran their chain line their procedure for painted chain was to run it through the zinc bath without the prior acid bath. This burnt off paint and other contaminants without adding any zinc. I was at their plant when they were doing this, when the smoke was so thick that it was impossible to see across the shop.

Yes I am aware burning off paint is possible but most galvanizers just refuse to do that as it as you say causes and almighty stink in the shop

My local galvanizers refuse to accept paint on anything.

I have a local grit blaster who will grit blast any paint off what I take him for about 1 GBP per batch