Let's talk about science: how ships protect against corrosion

In the heading "Let's talk about science" we will consider the option of combating corrosion on navy.

One of the problems faced by the fleets of all countries in the world without exception that have such is corrosion. The hulls of ships, boats, auxiliary vessels, hold compartments are corrosive due to the use of traditional materials. It would seem that the issue is being solved simply - the construction of warships and auxiliary vessels for the Navy (Navy) using composite materials - materials for which the risk of corrosion is minimized. However, this is a huge amount of money and the actual need for a huge amount of work to replace the entire crew, which means a huge time.

Therefore, today for protection against corrosion other options are proposed than reducing everything and everything to the use of composites.

One of the options for protecting ships from the effects of corrosion is special ship complexes, which consist of several basic elements.

Among the elements are a ship (sacrificial) anode, an ES (silver chloride) reference electrode, and an IPKZ - a pulse cathodic protection converter.

In the creation of such products in Russia, for example, specialists from the NRC "Kurchatov Institute" and PSS are involved.

Such a system allows for electrochemical protection of ship hulls by a potential shift. In this case, the surface of the ship is equipotential (the potential is the same in all areas), and the so-called cathodic process is carried out on each area of ​​the surface.

The rated output current in this marine corrosion protection system reaches 160 A with a ripple factor of no more than 1 percent. The efficiency is at least 90%.

On the components of the marine corrosion protection system

The ship anode is made of titanium alloy VT1-0 with a galvanized polymer coating.

A silver chloride reference electrode is used to obtain data on the potential with an ohmic component and the polarization potential without it. We are talking about the potentials of metal structures. Such electrodes are designed for a nominal operating temperature of 45 degrees Celsius, low - 0 degrees Celsius.

It should be noted that cathodic protection is actively used not only to protect ships from corrosion, but also to prevent harmful corrosion effects, for example, of metal piles - bridge supports.

Comments

[rocket757]

And on the car there are options for a plus on the ground, and even put zinc under the terminal !!! It still rots / rusts. There is no easy way to overcome this infection.
Difficult ways ... of course it is possible, with some positive effect, but if the metal does not meet the conditions of use, the agony will last, nothing more.
"Simple" option, change the car on time!

[Andrey.AN]

Why not overcome it in a simple way, it is much easier to make a cathode out of the body, and leave the anode on the lightning rod, place the load, the battery of the hybrid electric motor between the body and the lightning rod.

[rocket757]

"Wandering currents", they do not wander where we need to, but where they find their way ... with the greatest harm to the surrounding structures

[Andrey.AN]

This could be resolved in the joints with the hull, with resistances, so that they would not wander, however, the lightning can also be steered. The problem is energy consumption, but it goes away anyway.

[rocket757]

They try to regulate lightning, level it, etc., etc., but it, an infection, shies where it wants, and not where it was prepared for a trap ... the primordial element, however

[Andrey.AN]

no problem, in my opinion, to put a couple of automatic machines and a couple of powerful starters, knocking out one machine, the other turns it on through the starter.

[rocket757]

There are NO automatic machines against lightning. There are special protective devices, arresters. Various purposes and sizes. They met in human height.

[Andrey.AN]

the dimensions of the protection depend on its device, you can burn a two-meter fuse, or you can shut off the cascade in the gas, and the gas itself will not conduct above its ceiling.

[rocket757]

The arrester is not a fuse, it is reusable.
Lightning, ionizes, breaks through ANY GAS ... by the way, the best "gas", in this particular case, is a vacuum ... but due to technical, structural difficulties, they get by with a mix, atmospheric air. Self-renewable resource.

[Andrey.AN]

Why replenish gas in an ampoule in general, in a gas-discharge lamp that serves as a fuse in particular?

[rocket757]

Let's define. If we are talking about LIGHTNING, nothing but arresters, lightning rods and protective grounding can be used, because of the enormous energy and voltages !!!
Bulbs are bulbs, a source of light! As a protective, limiting device, it can be used, but according to the rules, special protective devices with specified parameters are used !!! The rest is all self-made.
Gas arresters, protective devices, limiting, but against lightning are used as secondary, additional devices ... usually where there is an antenna device, transmission network lines, overhead communication lines.
A fuse, as a special lightning protection device, is not used, because it triggers during overloads, a complete break in the electrical circuit.
Lightning protection is a big topic. Protection of electrical circuits, the topic is even more.

[Andrey.AN]

That is the point, the gas ampoule does not burn out, it simply will not allow more voltage and current, in a certain period, like a laser, than what the gas molecules are capable of transmitting. Excessive stress, just goes along a more difficult, but passable path, through more resistance.

[rocket757]

This is not protection against lightning, but against overvoltage.
I worked in the "field" and our antenna facilities were good. And as for lightning, such as are over the ocean, I have not seen anywhere else.
So, after a lightning strike, lightning protection arresters remained operable, and only holes in the panels remained from the gas arresters. And after all, only the residual energy reached them, and this is much, much, less than the energy of lightning.
It is not for nothing that the entire electrical circuit to the equipment has THREE degrees / line of protection. And that did not always help. It’s also good that the technique, mainly tube technology, was more durable. Semiconductors had to be replaced by boxes.
The element, however, is powerful, destroying everything.

[Andrey.AN]

No, just the specifics, lightning has a very high voltage, for this almost any body is a superconductor according to Ohm's law (the greater the voltage, the less resistance), these bodies burn.

[rocket757]

Here is a flame, for example, also cold plasma.
Have you ever seen how high-voltage lines are blocked by a flame? It happened with us when the reeds under 110kV power lines were not mowed in time!
And lightning, it's absolutely cool, ionizes and penetrates huge distances.

[Andrey.AN]

I even heard about lightning that its accelerating voltage when passing through water molecules causes thermonuclear fusion, forming helium from hydrogen. But if there is no water, then there is no thermonuclear catalyst either.

[seregatara1969]

And we, as ignoramuses, included a minus on the mass. That is why probably all positive copper wires rot

[rocket757]

There is a traditional line-up, a connection method that was established long before we figured out what it is desirable to connect PLUS to ground.
It is difficult to abandon the traditional, this is how much you need to change !!!
Besides, just changing the polarity of the connection, you won't get a great effect right away.
In connection, for example, initially PLUS on the mass, do you think nothing "rots" at all ??? Same thing, but slower.

[wildgluk]

You would learn to make metal as before in the tsarist times, an example to you is the oldest ship of our navy, the Commune! Or, for example, at our factory, German cranes built in 1912 are still working! In India, look under Delhi, an iron pillar has been standing for a thousand years ...

[petrol cutter]

I don’t know what it’s worth for a thousand years.
But you probably understand that the same "Komunna" was repaired a hundred times (and with modern methods) in fact. Otherwise, where did the welds come from on a completely (as stated) riveted ship ?!
By the way, nowadays the ship's metal is quite nothing.
Right now, the thickness of the metal is fundamentally different. Nobody makes sheathing 10 mm thick. Maximum five. And even less.
Such is the "squiggle".

[Brylevsky]

Nobody makes sheathing 10 mm thick. Maximum five. And even less.

You are wrong. The Japanese shipyard "Mitsubishi Heavy Industrious" produced container ships and car carriers in 2000-2012, and there the thickness of some hull sheathing sheets reached 25 - 42 mm. And from steel 10 mm thick, those ships were made ... superstructures. I have not yet seen hull plating thicker than 42 mm, but 15 -25 mm, this is the usual thickness of the hull sheets of a sea-going vessel of medium displacement at 15000 - 20000 tons. Maybe you meant the thickness of the hull skin of the warship?

[petrol cutter]

I don't know how, but everyone at once.
We are not talking about specific local reinforcements, but about the thickness of the sheathing as a whole for the ship.
On MRK 22800 five to six mm, "Comet 120 M" five to six mm panels, maran SDS - yes! Eight mm. But, as someone rubbed me, he is ice class. Although this is not accurate.
On "Comet120 M" there are certainly AMg thicknesses of fifteen or even twenty (the steering wheel, wings cannot be hung on tin ...) But, the same main deck which I am working on now, for example, has a variable thickness - three / five mm.

[Brylevsky]

I understood you. We are talking about different ships. I meant cargo ships with a displacement of 20000 to 100000 tons, and 42 mm of a hull sheet, this is not in the area of ​​reinforcement, this is a sheet of this thickness itself, over the entire area ... specifically, the bottom sheathing sheet, and the shirstrek is 20-25 mm ... What shipyard do you work at if it is not a military secret?

[petrol cutter]

JSC SZ "More". Yes, of course there is some dissonance here. Since we specialize in more or less fast ships / vessels. Where every mm of thickness leads to an increase in weight. As happened on the head 22800.
The engines could not accelerate the ship to the specified speed (according to rumors) and on subsequent orders, the thickness of the metal was reduced. Within reasonable limits.

[seregatara1969]

Railway tank up to 12 mm wall thickness

[petrol cutter]

These are completely different things and topics.

[Angelo Provolone]

Maximum five. And even less.

... does:
1. Corrosion on very old vessels.
2. See paragraph 1, if shipowners pay bribes to the Register inspector, which is a regular phenomenon in our "latitudes"

[cormorant]

Right now, the thickness of the metal is fundamentally different. Nobody makes sheathing 10 mm thick. Maximum five. And even less.

You got excited. I do not remember a ship that was less than 15 mm and these are the thinnest sheathing sheets. Wide belt and all 35-40 mm. Of course, this is if we are talking about sea vessels, not longboats.

[rocket757]

The old way, "red lead" saved from corrosion! Banned, not environmentally friendly.

[KCA]

That pillar looks beautiful from afar and is photographed, in reality, a terribly rusty piece of iron corroded very, very much, look at the photos not from the Indian tourism mines

[prior]

This problem should be entrusted to Chubais with his nanotechnology.
Something about him has not been heard lately. Apparently he learned to steal without unnecessary noise.
Well, if you fail .... reward.

[tihonmarine]

Quote: prior

Apparently he learned to steal without unnecessary noise.

He stole so much that there is no point in stealing.

[Vlad T]

It looks like A. Chubais does not steal, he is looking at who is allowed to steal at the expense of the budget. Prime Minister Medvedev regularly gave him billions of dollars and no reports ... The RF IC has more than once initiated evidentiary cases of billions of thefts by A. Chubais's subordinates, the cases were "put under the rug" and that ended ... So who is in charge in the RF ...

[tralflot1832]

We need to know the science. Murmansk miracle shipyard 80s. Docking of the GDR building is underway. I don’t remember the name. Let it be Rosa Luxemburg (there was one in the sefholod). Two ship hulls were put in to dismantle the protectors from the hull of the ship. Removing the protector they saw from the rear side strips of metal and this is clearly not zinc. That's what Soviet education means by chemical reactions, they determined that it was PLATINUM. The Germans used it for better contact of the zinc pair of the ship's hull. Information about the stuffing of these protectors was lost and who would have thought that such ambush. These two, having picked a couple of kilos of platinum, decided to sell it. In Soviet times, they sold it to a KGB officer who pretended to be a private jeweler. They got a very long term. The scandal was terrible. The management of the miracle of the shipyard had a pale appearance and an upset heart. Here you are and the science!!!

[syndicalist]

But what about Aurora in St. Petersburg for more than a hundred years in the water? And it seems that the replacement of the case was not reported.

[tihonmarine]

Quote: syndicalist

But what about Aurora in St. Petersburg for more than a hundred years in the water? And it seems that the replacement of the case was not reported.

Naive, the underwater part of the "Aurora" hull back in 91 was lying on a cutting pier in St. Petersburg, Coal Harbor, next to the BSMZ, opposite the Fish Port.

[Motorist]

Quote: syndicalist

What about Aurora

They changed it back in the 80s. And it stands in fresh water.

[BAI]

What about Aurora

There is no native corps. There is a fake. Native rotting in the Baltic.

[wildgluk]

They analyzed the pre-revolutionary metal and there are twice as many ferrite inclusions, now they say it is too expensive and expensive to make such a metal ..

[Aag]

What was that?
... "Let's talk about science" ...
All? Have you talked? .. Sparsely. The article does not even fit the advertising booklet. The author is aware that the corrosion of composites is no less extensive?
There is nothing to discuss ...

[Alexga]

Memories from youth, the best defense is a ship's red lead.

[Free wind]

I dare add, red lead, but it is now prohibited.

[Brylevsky]

the best defense is the ship's red lead.

Which is one of the protection components. Even the most thorough coating of the underwater part of the ship's hull with anticorrosive soil, made in compliance with the technology, does not provide, unfortunately, its long-term protection from the formation of galvanic vapors. Therefore, without anodic protection in the form of zinc bars on the hull of the ship (and inside it, in ballsat tanks), nowhere ... and even those, 5 years after replacement, look completely corroded.

[petrol cutter]

Well, this is somehow not serious ... Such a promising article title ...
I got ready to read a detailed report on the anti-corrosion protection of ships ... Compare the achievements with what is specifically used in our NW. On our orders.
What did the enemy come up with / how WE answered ... And here ...

[ved_med12]

I strongly agree! The topic is not covered, from the word at all! Electrochemical protection is presented as the only one, but what about improving the quality of steel through the use of alloying elements, applying protective paintwork materials and other protective coatings

[Brylevsky]

I prepared to read a detailed report on the topic of corrosion protection of ships.

The trouble with the overwhelming majority of articles on "VO" is that they are written by people who are completely far from the topic they touched upon, and some of them are even too lazy to understand the issue. There is a very good book on the topic of corrosion and its causes: "Rust and the fight against it" by A.S. Fedorov, 1954, series "Popular science library of a soldier and a sailor", at least when I was still studying, it was recommended to us by the teacher on "Theory and the structure of the ship." Written in simple and accessible language and the information contained in it, they are fundamental. So this is what I'm talking about ... You seem to be a specialist in ship repair. Why don't you pack up and sit down, write an article about your vision of the problem of protecting ships and vessels from corrosion? The topic is extremely relevant: no matter how perfect the ship is, rust grinds it away slowly but surely ... sometimes you hammer on the sheathing sheet with a sledgehammer, so rust "burdocks", along with layers of paint and soil, fall into the dock ... It's scary to talk about the ballast tanks of an elderly ship - you have to climb inside them yourself, or at least see a photo of what the ship's steel turns into in 10 years ...

[Brturin]

Quote: wildgluk

You would learn to do metal as it used to be in tsarist times,

Icebreakers were rare under the sovereign. and now ... people are working ...
Alexey Oryshchenko, Head of the Central Research Institute of Structural Materials "Prometey" - We have developed a technology that allows, with low alloying - up to 1% - to obtain high-strength, corrosion-resistant steels of high quality. At the same time, we proposed to manufacture the ice belt (reinforced lower part to resist ice) of ships from steel coated with stainless steel with maximum abrasion resistance and active cathodic protection to remove stray currents (so-called clad steel). This proposal was implemented on the world's most powerful nuclear icebreaker "50 Let Pobedy". It is more than 10 years old, and during this time its ice belt has literally lost microns, while usually the hull of a ship wears out 3-4 mm in a season. https://iz.ru/707287/arkadii-sosnov/po-khladostoikim-staliam-my-tochno-vperedi-planety-vsei

[BAI]

What does this article have to do with the topic "News"? All this was described in children's books in the 70s of the last century.

[Aleks2000]

Is this all science talk? 3 small pieces? Was it worth starting at all?

[Angelo Provolone]

PKM ships are built, but only minesweepers. Not profitable
Corrosion 0.1 - 0.25 mm / year. Thickness allowance is included in the design. protection saves the first half of the ship's life. On the second, everything quietly rusts.

[kig]

AND WHAT? What's the news about? All this has been known for a long time. Apparently, the VO editor does not know about this. And most importantly, active methods of combating corrosion have been successfully used for a long time.

[Ersh]

It looks like you need to stop reading this site. More and more articles, the authors of which are completely unaware of the issue, they are even too lazy to go to the Internet.