Is nickel magnetic or not - Metals and their processing

Nickel

Nickel is a simple substance, a ductile, malleable, transition metal of a silvery-white color; at ordinary temperatures in air it is covered with a thin film of oxide. Chemically inactive.

It belongs to heavy non-ferrous metals; it is not found in its pure form on earth - it is usually part of various ores, has high hardness, is well polished, is ferromagnetic - attracted by a magnet, in the periodic system of Mendeleev it is designated by the symbol Ni and has a 28th serial number.

STRUCTURE

It has a face-centered cubic lattice with a period a = 0.35238 å nm, space group Fm3m. This crystal structure is resistant to pressure of at least 70 GPa. Under normal conditions, nickel exists in the form of a b-modification, which has a face-centered cubic lattice (a = 3.5236 å).

But nickel subjected to cathode sputtering in an h2 atmosphere forms an a-modification, which has a hexagonal lattice of close packing (a = 2.65 å, c = 4.32 å), which transforms into a cubic lattice when heated above 200 °C.

Compact cubic nickel has a density of 8.9 g/cm3 (20 °C), atomic radius 1.24 å

PROPERTIES

Nickel is a malleable and malleable metal; it can be used to make very thin sheets and tubes. Tensile strength 400-500 Mn/m2, elastic limit 80 Mn/m2, yield strength 120 Mn/m2; relative elongation 40%; normal elastic modulus 205 H/m2; Brinell hardness 600-800 Mn/m2.

In the temperature range from 0 to 631K (the upper limit corresponds to the Curie point). The ferromagnetism of nickel is due to the structural features of the outer electron shells of its atoms.

Nickel is part of the most important magnetic materials and alloys with a minimum coefficient of thermal expansion (permalloy, monel metal, invar, etc.).

Reserves and production

Nickel is quite common in nature - its content in the earth's crust is about 0.01% (wt.). It is found in the earth's crust only in bound form; iron meteorites contain native nickel (up to 8%).

it is approximately 200 times higher in ultramafic rocks than in acidic rocks (1.2 kg/t and 8 g/t). In ultramafic rocks, the predominant amount of nickel is associated with olivines containing 0.13 - 0.41% Ni.

In plants there is an average of 5·10−5 weight percent of nickel, in marine animals - 1.6·10−4, in terrestrial animals - 1·10−6, in the human body - 12·10−6.

The bulk of nickel is obtained from garnierite and magnetic pyrite. Silicate ore is reduced with coal dust in rotating tube furnaces to iron-nickel pellets (5-8% Ni), which are then cleaned of sulfur, calcined and treated with an ammonia solution. After acidifying the solution, metal is obtained from it electrolytically.

Carbonyl method (Mond method): First, copper-nickel matte is obtained from sulfide ore, over which CO is passed under high pressure. Highly volatile tetracarbonylnickel [Ni(CO)4] is formed, the thermal decomposition of which produces a particularly pure metal.

Aluminothermal method for the recovery of nickel from oxide ore: 3NiO + 2Al = 3Ni +Al2O3

Source: http://mineralpro.ru/minerals/nickel/

Application of cobalt in the production of permanent magnets

Rolled metal calculator

The article discusses the use of cobalt for the production of permanent magnets. A description of the magnetic properties of cobalt is given, examples of specific alloys are given, and their advantages and disadvantages are considered.

A permanent magnet is an artificial product made of a hard magnetic material that has a high intensity of magnetic energy and a long period of demagnetization.

Modern permanent magnets are made by classical casting or using powder metallurgy technology by stamping or pressing (followed by sintering) finely dispersed powders of various alloys and metals with high magnetic saturation.

The power and physical characteristics of a magnet are determined by the chemical composition, crystal structure and proportions of its components. Permanent magnets produced using powder pressing technology can be made in almost any geometric shape (disk, cylinder, cube, prism, ring, etc.) and have a different direction of the magnetic field.

To make permanent magnets, metals with a pronounced ferromagnetic structure are used - ferromagnets.

When ferromagnets are alloyed, mutual reorientation of the atoms of their crystal lattices occurs, as a result of which the magnetic susceptibility of the alloy increases many times, it acquires the ability to be magnetized to saturation even in low external magnetic fields and maintain high magnetic properties for a long time. Ferromagnetic materials include iron, nickel, cobalt, as well as some of their alloys and compounds with non-ferromagnetic materials.

Figure 1. Magnet diagram.

Nonmetallic cobalt compounds were known in Egypt and China more than a thousand years ago. By adding cobalt pigments to a liquid solution, in Northern Mesopotamia they made a blue coating for ceramic tiles, and in the Middle Kingdom - an underglaze layer for the famous Chinese porcelain. First received in 1735

Swedish chemist Brandt, until the beginning of the twentieth century, the metal cobalt was practically not used in metallurgy due to unsuccessful experiments to create an alloy with iron.

Today, cobalt is an important component of heat-resistant and tool steels, and it has also become one of the most sought-after metals for the manufacture of permanent magnets.

Cobalt steels and alloys are currently the best materials for permanent magnets, the production of which accounts for more than 20% of all mined cobalt.

Metallic cobalt has a high saturation induction, which is expressed in its unique ability, with a single magnetization, to acquire a magnetic force that is many times greater than the power of the external field.

Another important property of cobalt is that it has a large coercive force (Hc), which prevents demagnetization and remagnetization of the material.

The word "coercive" comes from the Latin "coercitio", which translates as retention, so this characteristic can be described as the conservation (retention) of magnetic energy.

Magnetic chromium-cobalt steel EX5K5, containing 5-6% each of cobalt and chromium, has a coercive force of up to 170 oersted (A/m) with a residual induction (Br) of up to 8500 gauss (tesla).

The magnetic alloy of cobalt and platinum has no competitors at all in terms of the strength of magnetic energy, but it is quite expensive, which prevents its widespread use.

The Curie point of cobalt, which exists for every ferromagnet, expressed by the value of the phase transition temperature, upon reaching which a material magnetized to saturation becomes paramagnetic and loses its magnetic properties, is significantly higher than that of other metals with a ferromagnetic structure. For example: the Curie point for cobalt is 1127°C, for iron 770°C, for nickel 358°C, for gadolinium 19°C. This explains the stability of the properties of permanent magnets made of cobalt-containing alloys over a wide temperature range.

Modern technologies make it possible to accurately determine the chemical composition of the alloy for permanent magnets, giving them the characteristics that are in demand by consumers of the final product. The most common magnets today are products made from alloys of the iron-nickel-aluminum-cobalt (Fe-Ni-Al-Co) and samarium-cobalt (Sm-Co) systems.

Magnetic alloy iron-nickel-aluminum-cobalt (Fe-Ni-Al-Co)

To designate magnetic alloys based on iron (Fe) with the addition of nickel (Ni), aluminum (Al) and cobalt (Co), the foreign term “alnico” (English AlNiCo) is most often used, after the initial letters of the metals: aluminum (10-18 %), nickel (15-34%) and cobalt (18-40%). The Russian name for the alloy is UNDK.

The above proportions of the alloy provide permanent magnets with a large value of saturation induction, and as a consequence - a large value of residual induction.

Cobalt plays a key role in this aspect, since the more Co in the alloy, the higher the induction of its saturation and magnetic energy, which can reach values of 4000-5200 J/m3.

Pros and cons of iron-nickel-aluminum-cobalt (Fe-Ni-Al-Co) magnets
The disadvantages of the Fe-Ni-Al-Co alloy include not the highest coercive force (Hc), ranging from 36-58 oersteds (A /m), which, by the way, can be increased during production by increasing the content of aluminum and nickel.

Magnets made of Fe-Ni-Al-Co alloy, produced by pressing using powder technology, have mechanical strength several times greater than cast ones, but are 10-20% inferior in magnetic energy strength. An undoubted advantage of Fe-Ni-Al-Co permanent magnets is their high thermal stability, the ability to operate effectively at temperatures up to 550°C, while their Curie temperature is 810 - 900°C.

Permanent magnets based on the Fe-Ni-Al-Co alloy have good chemical and corrosion resistance, as well as a relatively low cost.

Samarium-cobalt (Sm-Co) magnetic alloy

The use of samarium-cobalt (Sm-Co) alloy for the production of permanent magnets is determined by the fact that it allows the creation of relatively lightweight products with very high magnetic force, including extremely small sizes for miniature equipment and devices (watches, headphones, smartphones, computers) .

Samarium (Sm) is a rare earth metal that looks like lead, but has mechanical properties similar to zinc.

Permanent magnets based on an alloy of samarium and cobalt are several times higher than the magnetic parameters of ferrite magnets and are leaders in the class of rare-earth magnets in terms of the maximum value of the coercive force, which can reach 1000-1200 kOe (kA/m), which is an order of magnitude higher than that of the alloy UNDC (Fe-Ni-Al-Co).

Advantages and disadvantages of samarium-cobalt (Sm-Co) magnets
The advantages of Sm-Co magnets are good strength (powder metallurgy) and a large amount of residual induction, excellent thermal stability at maximum operating temperatures of 250-350 ° C, which is explained by the Curie temperature of the alloy at 720 -800°C and above. Sm-Co magnets are resistant to corrosion and climatic factors, and therefore do not require a protective coating, which allows them to be used in aggressive environments with high temperatures, for example, in oil reservoirs. The disadvantages of Sm-Co permanent magnets include their high cost.

Using cobalt, a large number of magnets are produced, which, due to their high magnetic properties, are widely used in electrical engineering, machine tool building, instrument making, in the food, oil and gas, space industries and other areas where a permanent magnet is used as an element:

electric motors and generators;
DC/DC converters;
starting protection equipment;
pipeline integrity monitoring systems;
systems for magnetic processing and purification of various environments;
arc extinguishing devices;
batteryless telephone systems;
acoustic systems and relays;
computer components;
electric meters, magnetic induction tachometers, ohmmeters, flow meters (in metallurgy), various measuring equipment;
household electrical appliances.

Modern permanent magnets are extremely diverse in production method, physical and chemical characteristics, shape, and price, so you can choose the optimal product for almost any purpose. The number of applications for permanent magnets is constantly expanding, and cobalt alloys Fe-Ni-Al-Co and Sm-Co today play a major role in developing this trend.

Figure 2. Electric motor.

Source: https://www.metotech.ru/art_kobalt_2.htm

What affects the price of stainless steel, how to determine stainless steel

Scrap of non-ferrous, rare earth metals,
battery, cable scrap.

Stainless steel or stainless steel is part of the group of alloy steels and may include impurities that are designed to improve its characteristics: hardness, resistance to aggressive environments, corrosion and high temperatures.

What can be scrapped?

Stainless steel scrap collection centers are ready to accept:

pipes;
sheets;
shavings;
dishes;
cutlery;
metal scraps;
springs and other metal parts, and finished stainless steel products.

What affects the price of scrap?

The main evaluation criterion in the process of accepting stainless steel scrap is the percentage of nickel and chromium. The more nickel there is in a metal, the more expensive it is.

The price of scrap is also affected by:

Appearance and condition of the metal. The presence of rust will reduce the initial cost of scrap. And loose rust is the first sign of low quality metal.
Magnetic properties. Products that are not magnetic will cost more.
Density and durability of paintwork. A strong paint layer complicates the metal cleaning procedure, therefore reducing the cost of scrap.
Number of metal layers. Multilayer steel is less in demand, so its price will be lower.

How to quickly determine the quality of stainless steel

The cost of stainless steel directly depends on its quality. You can determine the quality of steel:

on low-quality stainless steel, a drop of water leaves a yellowish stain;
Salt will also help check the quality of the metal. On the surface of high-quality alloys, salt leaves no traces after drying;
high quality metal produces a short, direct spark.

nickel in various metal objects

The percentage of nickel in stainless steel is classified:

nickel 2-5% - may be contained in sanitary waste objects;
nickel 10% - present in kitchen utensils;
nickel 12% - found in plates, metal scraps, construction waste and other heat-resistant materials;
nickel 30-85% - metal alloys (matte);
nickel 95% - present in construction and plumbing rings, connectors, wire, powder, scrap and other high-alloy steel.

How to distinguish stainless steel from other metals

Taking into account the fact that stainless steel may or may not have this property, there is no need to focus on this indicator.

Therefore, in order to distinguish stainless steel from scrap of other metals, you need to clean a small area of the surface of the object being tested until the metal shines, then use a few drops of concentrated copper sulfate applied to the scrap.

Stainless steel under the influence of vitriol will become covered with a coating of red copper. It is almost impossible to determine whether a stainless steel belongs to the food category without special devices.

How to hand over stainless steel in Moscow

The procedure for accepting stainless steel in Moscow by MDM-Vtormetall is aimed at maintaining the interest of the donating party:

collection points are located in different parts of the city;
We provide pick-up service at any convenient time;
We provide free consultations;
We are considering the possibility of dismantling the facility ourselves.

Our scrap metal collection center tries to offer the most favorable prices for receiving stainless steel.

Use in medicine

This alloy, due to its high hygienic properties, rigidity, wear resistance and ease of cleaning from various contaminants, including bacteriological

Architectural and construction elements

Today, stainless steel, due to its hygienic properties, high strength and corrosion resistance, is used everywhere, including in architecture.

Bar equipment

In bars, like in any dining room, there is a kitchen where you can find a lot of different stainless steel equipment. But this article will talk about equipment for

Source: http://www.mdm-vtormetall.ru/stati/interesnoe-o-nerzhavejke/podrobnosti-o-lome-nerzhaveyushhej-stali.html

Nickel - what kind of metal is it?

Nickel is a metal with atomic number 28. It is designated by the symbol Ni. It has a silvery-white tint and under normal conditions is covered with an oxide film. Due to its ductility, nickel is easily forged.

Physical properties

Nickel is ferromagnetic, meaning that at temperatures below the Curie point it is magnetized in the absence of an external magnetic field. For nickel, the Curie point is 358 ⁰C. Metal does not tarnish in open air.

Basic physical properties of nickel:

The lattice structure is face-centered cubic.
Density under normal conditions is 8.902 g/cm3.
Melting point - 1453 ⁰С.
The specific heat of fusion is 17.61 kJ/mol.
Boiling point – 3000 ⁰С.
The specific heat of evaporation is 378.6 kJ/mol.
Molar heat capacity - 26.1 J/(K*mol)
Specific heat capacity - 0.440 kJ/(kg*K).
Thermal conductivity - 90.9 W/(m*K).
Specific electrical resistance - 0.0684 μOhm*m.

Story

Nickel was officially discovered in 1751 by chemist Axel Cronstedt, who found it in cobalt earth. However, even earlier it was excavated in the mountains of Saxony. Miners used the nickel-containing ore to make glass.

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Based on external signs, the Saxons initially mistook this ore for silver and tried to smelt it into the precious metal, but this did not work. In addition, when smelted, poisonous gas was released from the ore, which harmed miners.

Attempts to extract copper from this ore also failed.

As a result, at the end of the 17th century. The Saxons called the ore "kupfernickel", which translated means "copper devil". This is due to the fact that the miners considered the release of poisonous gas to be the machinations of evil spirits living in the mountains. It was kupfernickel that was studied by Axel Kronstedt in 1751. He obtained a green oxide from it and reduced it to a metal that was previously unknown to science. The chemist named this metal nickel.

In 1775, Thorbern Olaf Bergman obtained nickel in a purer form and described its properties in more detail. He found out that the composition of this metal is more similar to iron than to copper. At the end of the 18th – beginning of the 19th centuries. Many chemists, starting with Joseph Louis Proust, studied nickel in detail. In 1804, the German chemist Jeremiah Benjamin Richter finally obtained pure metal, and nickel was finally established as a chemical element.

Biological role

Nickel is a trace element that is necessary for all living organisms. Its average content in plants is 0.00005%, in terrestrial animals - 0.000001%, in marine animals - 0.00016% of body weight.

The role of nickel in the body is not fully understood. It is known that it participates in enzymatic reactions and affects oxidative processes. It is found in the lungs, liver, muscles, pancreas and thyroid glands, and some parts of the brain. The trace element also accumulates in keratinized tissues of humans, animals and birds, including hair and feathers.

Excessive nickel content in plants leads to ugly forms, in animals - to various eye diseases (keratoconjunctivitis, keratitis).

Nickel vapors and dust are toxic and can cause damage to the skin, lungs and nasopharynx, and frequent inhalation of metal vapors is dangerous due to the appearance of malignant neoplasms.

Occurrence in nature and production

Most nickel is found in deep layers. In the earth's crust it is 0.0058%, in ultramafic rocks it is 0.2%. If we believe the hypothesis that the earth's core is composed of nickel iron, the total nickel content in the earth is approximately 3%. Nickel is also found in some meteorites.

In the earth's crust, this metal is adjacent to iron and magnesium, with which it has a similar valency. In magnesium and iron minerals, nickel is contained as an isomorphic impurity. There are also 53 nickel minerals known to science. Most of them were formed under the influence of pressure and high temperatures, for example, when magma solidified. Sulfide ores containing this metal contain copper. Some nickel ores include iron, sulfur, arsenic, cobalt, magnesium.

Most of this metal is mined in Russia. Large nickel mines are also found in Canada, Australia, New Caledonia, Indonesia and Cuba.

Most nickel (about 80%) is obtained from sulfide copper-nickel ores, much less - from silicate (oxidized) ores.

Chemical properties

Nickel is chemically inactive. It forms a surface oxide film, which is why it is stable in the atmosphere, alkali, many acids and water. The metal does not corrode. Forms two oxides (NiO and Ni2O3) and two hydroxides (Ni(OH)2 and Ni(OH)3).

Nickel chloride, nitrate, sulfate and nitrate are four soluble salts. They have a yellow or yellow-brown tint and color solutions green. Nickel phosphate, oxalate and sulfides (black, green and bronze) are insoluble salts.

The metal absorbs gases (carbon, hydrogen and many others), which worsen its mechanical properties. It interacts with oxygen at temperatures above 500 ⁰С.

In a finely dispersed state, nickel spontaneously ignites in air. When heated, it combines with halogens. It forms a sulfide when burned in sulfur, and when NiO oxide is heated with sulfur, a monosulfide is obtained. The metal also reacts with nitric acid to form nickel nitrate and nitric oxide.

In terms of chemical properties, it is most similar to iron and cobalt, and to a lesser extent to noble metals and copper. It burns only in powder form and exhibits variable valence in compounds (most often divalent). Forms complex and coordination compounds.

Application

The widest area of application of nickel is the production of alloys of various metals. It is fused:

With steel. This increases the chemical resistance of the alloy: all stainless steels contain nickel.
With iron. This alloy has a low coefficient of thermal expansion, due to which it is successfully used for the manufacture of various parts for electrical appliances.
With cobalt and magnesium. A heat-resistant alloy is formed that can withstand high temperatures up to 500 ⁰C and is resistant to corrosion.
With gold and silver. This so-called “white gold” is a durable jewelry alloy.
With chrome. As a result, nichrome is formed - a heat-resistant, creep-resistant, ductile alloy that holds its shape well.
With iron, copper and chrome. This alloy is characterized by high magnetic susceptibility.

Nickel alloys have a high degree of toughness, which is why they are used in the manufacture of armor. Many alloys are used in gas turbine units and nuclear reactor structures. They are also used to make heating elements and coins. Alloys are widely used in the production of batteries.

Nickel is also used in its pure form: pipes, sheets, etc. are made from it, and in chemical laboratories it serves as a catalyst for many reactions. Specialized chemical equipment is also made from metal. Nickel oxide is used in the production of glass, ceramics and glazes. Nickel plating is used for many metals - creating a nickel coating to protect against corrosion.

Nickel is used to make coils of electronic cigarettes, and it is used to wrap the strings of musical instruments. In medicine, this element is used for prosthetics and the manufacture of braces.

Source: https://ferrolabs.ru/blog/nikel/

How to distinguish nickel from other metals

When choosing jewelry in a jewelry store, the eye certainly falls on silver. This metal is no worse than gold or platinum, and many girls like it much better, but its price is much more reasonable. But this precious metal is counterfeited very often, and in order not to fall for scammers, you must be able to distinguish the original from the fake.

About silver

Since ancient times, silver has been valued for its beauty and physical qualities. In nature, it is found in the form of nuggets, sometimes reaching enormous sizes; the largest nugget found during smelting yielded 20 tons of pure silver.

Unfortunately, most of the silver that can be found is found in combination with other substances, which makes it very difficult to smelt pure metal nuggets.

If we talk about the physical properties of silver, then special attention is paid to its ductility; from 1 g of silver the thinnest wire 2 km long is obtained, as well as the fact that this metal is considered precious and is used by jewelers - its ability not to oxidize under the influence of oxygen.

Cupronickel is an alloy of copper, nickel and zinc. Externally, this metal is very similar to silver, which is what many take advantage of by selling counterfeits made of cupronickel under the guise of this precious metal. Cupronickel is often used to make dishes and, less commonly, jewelry.

But in this case, how to distinguish cupronickel from silver? Reviews from customers and experts say that the first and main rule is to think about where exactly to buy it. This is where the whole process should begin. You will not need to find out how to distinguish silver from cupronickel if the product was purchased at a large jewelry store.

He will not allow himself to ruin his reputation by selling counterfeits. It's a different matter for pawn shops and those who want to sell jewelry "from hand", they will most likely sell a fake.

Most often, a fake can be found on vacation, for example, in Egypt or Thailand. In such places, jewelry is often bought at markets. Of course, it's worth trying out the local flavor, but it can be too expensive if you are gullible.

The easiest way to determine if silver is real is to heat the item, for example, by rubbing it on your hand, silver has a high thermal conductivity and will heat up much faster than any other metal.

There are other ways to distinguish silver from other metals and cupronickel, using a magnet, needle or chalk.

Tactile method

There are several tactile ways to distinguish silver from cupronickel and other fakes. One of them was described above, namely, to heat the product.

But, in addition to temperature, after heating an object by rubbing it with your hand, you should pay attention to the skin.

If there are no stains left on it, most likely it is high-quality silver, but dark marks remaining on the skin indicate that the product contains too much zinc, which is harmful to the body, and you should not wear such jewelry or use such utensils.

The authenticity of silver can also be determined by the weight of the item: silver is much heavier than other metals. This task is best handled by a professional, but an ordinary person can determine its authenticity by simply comparing the weight of the item with a similar silver one.

Try

Also, one of the simplest ways to check the authenticity of metal, which can be used right in the store, is to check the sample. If a fake has one, it will be erased or unclear. The “MNC” symbol, which stands for magnesium, nickel, zinc - the composition of the cupronickel alloy, can also serve as a difference between silver and cupronickel.

Products from different countries may have different markings, but not a single manufacturing country has a standard with simply the inscription “925”; there are always other signs - images or inscriptions; it is with fakes that the standard is most often found only in the form of a number.

This will help those who are wondering how to distinguish cupronickel from silver, but did not have any available means, such as chalk, with them.

Magnet

A less reliable, but still valid method for distinguishing silver from other metals is a magnet. Very often I insert silver parts into products made from ordinary, base metals. For example, these could be links in a chain with a sample. In this case, a magnet can help; silver is never attracted to it. But this method is not reliable, since not only does the magnet not attract silver, but cupronickel and non-ferrous metals also do not react to the magnet.

Needle

Another common way to counterfeit silver jewelry or tableware is to coat copper or other metal with a thin layer of silver. In this case, a regular needle can help distinguish a fake. It is enough to scratch the product with it, and if dark metal appears inside, then it is definitely a fake. However, this method is not suitable for those who are afraid of ruining the appearance of the item.

Sulfur ointment and lapis pencil

Sulfur ointment, which can be bought at any pharmacy, will also help to distinguish silver: when you rub this substance on a silver item, a black mark will appear on it within an hour. The only negative is that you will have to scrub the silver from the blackness. There is also a way to identify exactly the cupronickel alloy; to do this, you need to run a lapis pencil over the metal - it will leave a dark mark on the product.

Iodine

You can check the authenticity with another means available at any pharmacy, namely iodine.

Cupronickel and other metals do not change their appearance under the influence of iodine; low-quality silver, with a large percentage of zinc impurities, will change its color to blue, but real silver, as soon as iodine is dropped on it, will turn black.

But this method is also undesirable for those who do not know how to clean silver. But don’t despair, there’s plenty of advice on the Internet on how to do this. The most reliable way is to use a special cleaning cloth or silver cleaning solution.

Chalk

Another method that can be used in a jewelry store before purchasing a piece is to rub it with regular chalk. When it comes into contact with silver, the chalk becomes covered with a black coating. Unfortunately, this method will not help if the fake is coated with a layer of silver.

And one more rule that is worth taking note when coming to a jewelry store or, especially, buying jewelry secondhand: before purchasing a product, you should find out the silver rate. Information like this can be very useful if you know how to use it.

It is important to remember that the price of jewelry or any other silver product cannot be less than or equal to the cost of silver of the corresponding weight. The price quoted by the seller also includes labor. If a seller offers a heavy ring or pendant for next to nothing, it is one hundred percent fake. Accuracy and attentiveness when choosing purchases will help you avoid unnecessary expenses.

Source: http://ooo-asteko.ru/kak-otlichit-nikel-ot-drugih-metallov/

Stainless steel that is magnetic - Is stainless steel magnetic or not: how to determine stainless steel

alexxlab | 03/10/2018 | 0 | Questions and answers

Is stainless steel magnetic or not: how to determine stainless steel

Considering the fact that stainless steel today is produced in a wide variety of brands, it is impossible to unequivocally answer the question of whether it is magnetic or not. The magnetic properties of stainless steels depend on the chemical composition and, accordingly, on the internal structure of the alloys.

A portable metal analyzer allows you to quickly determine the content of chemical elements and make a conclusion about the quality of stainless steel

What determine the magnetic properties of materials?

A magnetic field with a certain level of its intensity (H) acts on bodies placed in it in such a way that it magnetizes them. In this case, the intensity of such magnetization, which is designated by the letter J, is directly proportional to the field strength. The formula by which the intensity of magnetization of a certain substance is calculated (J = ϞH) also takes into account the coefficient of proportionality Ϟ - the magnetic susceptibility of the substance.

Depending on the value of this coefficient, all materials can be included in one of three categories:

paramagnetic materials – coefficient Ϟ is greater than zero;
diamagnetic materials – Ϟ is equal to zero;
ferromagnets are substances whose magnetic susceptibility is significant (substances, which, in particular, include iron, cobalt, nickel and cadmium, are capable of actively magnetizing, even when placed in weak magnetic fields).

Directions of action of magnetic moments of neighboring atoms in substances of different magnetic nature

The magnetic properties that stainless steel has are also associated with its internal structure, which can include austenite, ferrite and martensite, as well as combinations thereof. At the same time, the magnetic properties of stainless steel are influenced both by the phase components themselves and by the ratio in which they are found in the internal structure.

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Stainless steels with good magnetic properties

Stainless steel, in which the following phase components predominate, has good magnetic properties:

Martensite is a ferromagnet in its pure form.
Ferrite - this phase component of the internal structure of stainless steel, depending on the heating temperature, can take two forms. This structural form becomes ferromagnetic if the steel is heated to a temperature below the Curie point. If the heating temperature of the stainless steel is above this point, then high-temperature delta ferrite, which is a pronounced paramagnet, begins to predominate in the alloy.

From all of the above, we can conclude that the stainless steel that is magnetic is one in which martensite predominates in its internal structure. Like regular carbon steels, these alloys react to magnets. By this feature they can be distinguished from non-magnetic ones.

The ability of stainless steel to magnetize does not affect its corrosion resistance

Stainless steels, in which ferrite or its mixture with martensite predominate, are most often also classified as ferromagnetic, but their properties may vary depending on the ratio of the phase components of their internal structure.

Stainless steel, the magnetic properties of which can change, are mainly chromium and chromium-nickel alloys, which may belong to one of the following groups.

Martensitic

Steels with a martensitic internal structure, which, like conventional carbon steels, can be strengthened by quenching and tempering. Such stainless steel, in addition to general engineering enterprises, is actively used in everyday life (in particular, cutlery and cutting tools are made from it). The most common grades of such magnetic steels, products from which are produced with heat treatment and can be subjected to finishing grinding and polishing, include 20Х13, 30Х13, 40Х13.

Steel grade 30Х13 is less ductile than alloy 20Х13, despite its similar composition (click to enlarge)

This category also includes the 20Х17Н2 alloy, which is characterized by a high chromium content in its chemical composition, which significantly enhances its corrosion resistance. Why is this stainless steel popular? The fact is that, in addition to high resistance to corrosion, it is characterized by excellent workability using cold and hot stamping and cutting methods. In addition, products made from such material are well welded.

Ferritic

A common ferritic-type magnetic steel, which, due to the low carbon content in its chemical composition, is softer than martensitic alloys, is 08Х13, which is actively used in food production. Such stainless steel is used to make products and equipment intended for washing, sorting, grinding, sorting, and transporting food raw materials.

Mechanical properties of steel 08Х13

Martensitic-ferritic

A popular brand of magnetic stainless steel, the internal structure of which consists of martensite and free ferrite, is 12X13.

Corrosion resistance of steel grade 12Х13 (other name 1Х13)

Non-magnetic stainless steels

Stainless steels that are not magnetic include chromium-nickel and chromium-manganese-nickel. They are usually divided into several groups.

Austenitic

The most popular brand of such stainless steels, which occupy a leading place among non-magnetic steel alloys, is 08Х18Н10 (international analogue according to AISI 304 classification).

Steels of this type, which also include 08Х18Н10, 08Х18Н10Т, 12Х18Н10Т, 10Х17Н13М2Т, are actively used in the production of equipment for the food industry; kitchenware and cutlery; plumbing equipment; containers for food liquids; refrigeration equipment elements; containers for food products; medical supplies, etc.

Composition and application of austenitic steels

The great advantages of such stainless steel, which does not have magnetic properties, are its high corrosion resistance, demonstrated in many aggressive environments, and manufacturability.

Austenitic-ferritic

Steels of this group, the most popular grades of which are 08Х22Н6Т, 08Х21Н6М2Т and 12Х21Н5Т, are distinguished by a high chromium content and a low nickel content. To give such a stainless steel the required characteristics (an optimal combination of high strength and good ductility, resistance to intergranular corrosion and stress-corrosion cracking), elements such as copper, molybdenum, titanium or niobium are introduced into its chemical composition.

Chemical composition of some industrial grades of austenitic-ferritic steels (click to enlarge)

In addition to the above, stainless steels that are not magnetic include alloys with an austenitic-martensitic and austenitic-carbide structure.

How to Determine Whether Magnetic or Non-Magnetic Steel is Stainless

Considering all of the above, we can draw the following conclusion: even if steel has magnetic properties, this does not mean at all that it cannot be classified as a stainless-type alloy.

There is a fairly simple way to check whether magnetic steel is stainless steel.

In order to determine this, it is necessary to clean the surface area of the product being tested to a metallic shine, and then apply a few drops of concentrated copper sulfate to this area.

The fact that this is stainless steel is indicated by a coating of red copper that covers the cleaned area. This simple method allows you to very accurately determine whether magnetic steel is stainless. But it is almost impossible to check (and especially determine at home) whether stainless steel belongs to the food category.

If you decide to check whether magnetic steel is stainless or not, keep in mind that its properties, such as the ability to magnetize, do not in any way impair its corrosion resistance.

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Source: https://stankotec.ru/raznoe/nerzhavejka-kotoraya-magnititsya-nerzhavejka-magnititsya-ili-net-kak-opredelit-nerzhaveyushhuyu-stal.html

Magnetic or not

We make most of our products from stainless steel. The second bottom of the chimney must be made of stainless steel - this part absorbs hot smoke from the chimney, so the requirements for anti-corrosion protection are increased here.

Sometimes our clients try to check the quality of stainless steel using a magnet - there is a “folk way”. But do not rush to accuse the supplier of deception if you suddenly discover the magnetic properties of “stainless steel”. In fact, more than 250 grades of steel are now produced, which have the general name “stainless”, but are very different in composition and properties and may well be magnetic.

Modern classification of stainless steel

Stainless steel is a type of alloy steel that is resistant to corrosion due to its chromium content. In the presence of oxygen, chromium oxide is formed, which creates an inert film on the surface of the steel, protecting the entire product from adverse influences.

Not every grade of stainless steel demonstrates the resistance of chromium oxide film to mechanical and chemical damage. Although the film recovers when exposed to oxygen, special grades of stainless steel have been developed for use in aggressive environments.

The first conditional type of division into groups:

Food
Heat resistant steel
Acid resistant steel

The second type of classification is by microstructure:

Austenitic - non-magnetic steel with the main components of 15-20% chromium and 5-15% nickel which increases corrosion resistance. It is well suited to heat treatment and welding. It is the austenitic group of steels that is most widely used in industry and in the production of fasteners.
Martensitic steels are significantly harder than austenitic steels and can be magnetic. They are hardened by quenching and tempering like simple carbon steels, and are used mainly in the manufacture of cutlery, cutting tools and general engineering. More susceptible to corrosion.
Ferritic steels are much softer than martensitic steels due to their low carbon content. They also have magnetic properties.

Stainless steel markings

In Russia and the CIS countries, an alphanumeric system has been adopted, according to which numbers indicate the content of steel elements, and letters indicate the name of the elements. The designations common to all are the letter designations of alloying elements: H - nickel, X - chromium, K - cobalt, M - molybdenum, B - tungsten, T - titanium, D - copper, G - manganese, C - silicon.

Standard stainless steel, according to GOST 5632-72, is marked with letters and numbers (for example, 08Х18Н10Т). In the United States, there are several systems for naming metals and their alloys. This is due to the presence of several standardization organizations, these include AMS, ASME, ASTM, AWS, SAE, ACJ, ANSI, AJS. It is quite clear that such marking requires additional clarification and knowledge when trading metal, placing orders, etc.

Europe (EN)	Germany (DIN)	USA (AISI)	Japan (JIS)	CIS (GOST)
1.4021	X20Cr13	(420)	SUS 420 J1	20Х13
1.4028	X30Cr13	(420)	SUS 420 J2	30Х13
1.4031	X39Cr13	SUS 420 J2	40Х13
1.4016	X6Cr17	430	SUS 430	12Х17
1.4510	X3CrTi17	439	SUS 430 LX	08Х17Т
1.4301	X5CrNI18-10	304	SUS 304	08Х18Н10
1.4541	X6CrNiTi18-10	321	SUS 321	08Х18Н10Т
1.4401	X5CrNiMo17-12-2	316	SUS 316	08Х17Н13М2
1.4404	X2CrNiMo17-12-2	316 L	SUS 316 L	03Х17Н14М2
1.4571	X6CrNiMoTi17-12-2	316 Ti	SUS 316 Ti	10Х17Н13М2Т
1.4435	X2CrNiMo18-14-3	316 L	SUS 316 L	03Х17Н14М2
1.4878	X12CrNiTi18-9	321H	12Х18Н10Т
1.4845	X12CrNi25-21	310 S	20Х23Н18

Of the variety of brands, we use three main ones in our production - AISI 304, AISI 316 and AISI 430.

Properties, characteristics and features of nickel composition

Nickel is characterized by excellent corrosion resistance, high strength, aesthetic appeal and the ability to take any shape given to it. Due to its properties, this metal has long been used in construction. More than 60% of nickel goes into the production of stainless steel.

Nickel is used to build houses, perform interesting architectural designs, decorate walls and make drainpipes. Nickel is present everywhere in our lives. Therefore, today we will look at its composition, structure and properties of nickel.

Nickel is white with a silver tint. This metal is often combined with other materials. As a result, alloys are formed.

Nickel is found in food, the earth's crust, water and even in the air.
Nickel has a face-centered cubic lattice (a = 3.5236A). In its normal state it is presented in the form of the β-modification. During cathode sputtering, it transforms into the α-modification with a hexagonal lattice. If you further heat nickel to 200°C, its lattice will become cubic.
Nickel has an unfinished 3d electron shell, so it is classified as a transition metal.
The element nickel is part of the most important magnetic alloys and materials in which the coefficient of thermal expansion is minimal.

Nickel, which is not processed and mined from nature, consists of 5 stable isotopes. In the periodic table of Mendeleev, nickel is numbered 28. This element has an atomic mass of 58.70.

Next we will talk about the magnetic, technological properties of nickel, its mechanical, physical and technical characteristics.

Density and mass

Nickel belongs to a number of heavy metals. Its density is twice that of titanium metal, but is equal in numerical value to the density of copper.

The numerical value of the specific density of nickel is 8902 kg/m3. Atomic mass of nickel: 58.6934 a. e.m. (g/mol).

Mechanical characteristics

Nickel has good malleability and ductility. Thanks to these characteristics, it can be easily rolled. It is quite easy to make thin sheets and small pipes from it.

At temperatures from 0 to 631 K, nickel becomes ferromagnetic. This process occurs due to the special structure of the outer shells of the nickel atom.

The following mechanical characteristics of nickel are known:

Increased strength.
Tensile strength equal to 450 MPa.
Highly plastic material.
Corrosion resistance.
High melting point.
High catalytic ability.

The mechanical characteristics of the described metal depend on the presence of impurities. The most dangerous and harmful are sulfur, lead, bismuth, zinc and antimony. If nickel is saturated with gases, its mechanical properties will become worse.

Thermal and electrical conductivity

Nickel metal has the following thermal conductivity: 90.1 W/(m K) (at a temperature of 25°C).
The electrical conductivity of nickel is 11,500,000 Sim/m.

Corrosion resistance

Corrosion resistance refers to the ability of a metal to resist destruction when exposed to an aggressive environment. Nickel is a material with high corrosion resistance.

Nickel will not rust in the following environments:

Ambient atmosphere. Nickel has good resistance to high temperatures. If nickel is exposed to an industrial atmosphere, it is always covered with a thin film, which leads to tarnishing of the nickel.
Alkalies in hot and cold form, as well as their molten states.
Organic acids.
Inorganic acids.

In addition, nickel does not rust in hot alcohols and fatty acids. Due to this, this metal is widely used in the food industry.

The chemical industry also widely uses nickel. This is due to the corrosion resistance of nickel to high temperatures and high concentrations of solutions.

Nickel alloys have increased corrosion resistance. Especially compounds of this metal with iron, molybdenum, chromium and copper.

Nickel is susceptible to corrosion under the following environmental conditions:

Sea water.
Alkaline solutions of hypochlorites.
Sulfur or any medium containing sulfur.
Solutions of oxidizing salts.
Ammonia hydrate and ammonia water.

Nickel toxicity is discussed below.

Temperatures

The following thermodynamic properties of nickel are known:

Nickel melting point: 1726 K or 2647 °F or 1453 °C.
Nickel boiling point: 3005 K or 4949 °F or 2732 °C.
Casting temperature: 1500-1575 °C.
Annealing temperature: 750 – 900 °C.

Toxicity and environmental friendliness

In large quantities, nickel has a toxic effect on the body. If we are talking about taking it with food, then an increased content of this element will certainly pose a health threat.

A frequently encountered negative consequence from an excess of nickel is allergies. Also, when exposed to this metal (in large quantities) on the body, stomach and intestinal disorders occur, and the content of red blood cells necessarily increases. Nickel can cause chronic bronchitis, kidney stress and lung dysfunction. An excess of nickel provokes lung cancer.

THIS IS INTERESTING: At what temperature does cast iron melt?

If drinking water contains 250 parts of nickel per million parts of water, then this level can cause blood disease and kidney problems. However, this is quite rare.

Nickel is found in tobacco smoke. Inhalation of this nickel-containing smoke or dust leads to bronchitis and impaired lung function. It is possible to obtain this substance under hazardous production conditions or in environmentally unfavorable areas.

Nickel toxicity is only a danger if it enters the human body in large quantities. If nickel is used in industry and construction, then it is not dangerous.

Nickel also has the following characteristics:

The electrical resistivity of nickel is 68.8 nom m.
Chemically, nickel is similar to iron, cobalt, cuprum and some noble metals.
Nickel reacts with oxygen at a temperature of 500 C.
If nickel becomes finely dispersed, it can spontaneously ignite.
Nickel does not react with nitrogen even at very high temperatures.
Nickel dissolves more slowly than iron in acids.

Source: http://stroyres.net/metallicheskie/vidyi/tsvetnyie/nikel/svoystva-osobennosti-sostava.html

Is stainless steel magnetic or not? Grades and properties of stainless steel

March 27, 2019
Miscellaneous
Svetlana Pavlova

It is impossible to imagine the absence of anti-corrosion steel in modern life. The emergence of a stainless alloy made it possible to make great strides in many areas of the national economy. Only the addition of chromium to steel makes it resistant to corrosion. But when using it, consumers often have a question: is stainless steel magnetic or not? That's what we'll talk about in this article.

What is anti-corrosion steel?

Steel that does not become rusty during use is popularly called stainless steel. It is obtained from an alloy of iron with carbon and various alloying additives: nickel, chromium, niobium, titanium. Each of these components enhances or reduces certain properties of the alloy - magnetism, strength, hardness, ductility, corrosion. The main quality of stainless steel is corrosion resistance. It just depends on the chromium content in it.

The more of this metal in the alloy, the less susceptible it is to corrosion. Therefore, all steels that are resistant to rust contain at least 10.5% chromium. The uniqueness of this metal is that when it reacts with oxygen, it creates an oxide film on the surface of the product, which prevents the alloy from reacting with aggressive environments. Moreover, if the surface is damaged, the film forms again after the oxidation of chromium with oxygen.

Stainless steel classification

And yet, is stainless steel magnetic or not? Depending on the composition of chemical elements and internal structure, it can be magnetic or not, and is divided into the following types:

Ferritic - contain more than 20% chromium, are resistant to aggressive environments, are endowed with magnetic properties, are affordable, and are widely used.
Austenitic - do not corrode, contain large amounts of nickel and chromium, are flexible and durable. Easy to weld, belong to non-magnetic alloys.
Martensitic - anti-corrosion alloys can be exposed to high temperatures, do not emit harmful fumes, and have increased wear resistance and strength.
Combined - special stainless steels that combine the properties of all the above groups. Produced according to individual customer requests. The greatest demand is for austenitic-martensitic and austenitic-ferritic alloys.

It should be noted that the magnetic properties of steel do not affect its corrosion properties.

Magnetic properties of materials

All materials according to their magnetic properties are divided into:

Paramagnets - tin, platinum, aluminum - increase the external magnetic field due to the coincidence of molecular currents with it.
Diamagnets - copper, silver, zinc, their internal field weakens the external one.
Ferromagnets - iron, cobalt, nickel, in which magnetization is greatly enhanced even under weak influence of an external field.

Why is stainless steel magnetic? This happens when the external magnetic field is strengthened by the internal one. Moreover, the more intensely they increase each other, the magnetization will be stronger. In addition, the magnetic properties of stainless steel depend both on the ratio of alloy additives that make up its composition, and on the phase state of the steel.

How to identify a stainless steel product?

Many consumers often try to determine on their own what metal a particular household item is made of. Visually, ordinary steel cannot be distinguished from stainless steel, so it is customary to use a magnet to check.

There is an opinion that real anti-corrosion steel is not magnetic. Can stainless steel be magnetic or not? Anything can happen. Therefore, this method of verification does not give a reliable result.

Sometimes it happens that a product is attracted to a magnet, but serves for a long time without changing its qualities.

And vice versa, which does not react to it in any way, upon contact with water it becomes covered with rust. Corrosion resistance can be correctly determined by examining its chemical composition, which is impossible to do at home. To protect yourself from counterfeits, it is better to purchase household products in branded stores.

Stainless steel that is not magnetic

Very often, alloys with a high content of chromium, nickel and manganese are used to produce anti-corrosion steel. They are used to produce a large number of different equipment and products for use in various fields. Non-magnetic steels include:

Austenitic. They are used to make equipment for ships, refrigerators, the food industry, kitchen utensils and plumbing equipment.
Austenitic-ferritic. The main advantages of such alloys are strength and increased resistance to cracking.

People most often in everyday life come across equipment and products made from these steels, so to the question “Is stainless steel magnetic or not?” and answer in the negative, although this is incorrect.

Anti-corrosion magnetic steels

Alloys that are resistant to rust but are strongly attracted to a magnet include:

Martensitic - the material has high strength, can be ground and polished well, is very resistant to corrosion, and can be easily processed by stamping, cutting and welding. In addition to the manufacture of industrial equipment, it is used for the manufacture of cutlery. Therefore, the question of whether stainless steel is magnetic or not can be answered positively.
Ferritic – the most popular grade of steel with magnetic properties is AISI 430, used for the production of food equipment.

Use of chromium-nickel steel

Anti-corrosion steel 12Х18Н10Т is an environmentally friendly and durable material.

The composition of the chromium-nickel alloy, in addition to the main component - iron, includes up to 19% chromium, which provides it with strong anti-corrosion properties, and 11% nickel, which transfers it to the class of austenites and imparts flexibility, strength and heat resistance.

Due to its characteristics, it is widely used. Many people are interested in whether steel grade 12Х18Н10Т is magnetic or not? It is non-magnetic, like all austenitic alloys, and is used in the following industries:

Chemical - aggressive acids: acetic, nitric, phosphoric are transported through pipes made of this grade of steel.
Food – dairy, meat, alcohol.
Mechanical engineering – production of parts in contact with acids and alkalis, production of welded equipment, exhaust system manifolds.
Petroleum - for the manufacture of pipes.

In addition, chromium-nickel alloys are used in the fuel and energy sector. Furnace fittings and heat exchangers are made from them.

Conclusion

Now you know which stainless steel is magnetic and which is not, and that these properties do not have any effect on the quality of the purchased product. At home, there is no way to check whether the dishes or plumbing equipment you purchased will rust or not. Everything will become clear during operation. To avoid making a mistake in your choice, make purchases at large retail outlets and from well-known manufacturers.

Source: https://truehunter.ru/458381a-nerjaveyka-magnititsya-ili-net-marki-i-svoystva-nerjaveyuschey-stali

Useful

Designation of alloying elements in stainless steels
The influence of the main alloying elements on the properties of stainless steels
Compliance of foreign standards with Russian GOST
Why is one brand of stainless steel magnetic and another not?
What is “Food Stainless Steel”?
The most common types of surface of stainless steel sheets

Designation of alloying elements in stainless steels

In the initial part of the stamp there are numbers (two or one) showing the carbon content.
Two numbers indicate its average content in the alloy in hundredths of a percent, and one – in tenths. There are also steels that do not have numbers at the beginning of the brand name. This means that the carbon content in these alloys is within 1%.
The letters that can be seen behind the first digits of the brand name indicate what the alloy is made of.
The letters that give information about a particular element in its composition may or may not have numbers. If there is a number, then it determines (in whole percentages) the average content of the element indicated by the letter in the composition of the alloy, and if there is no number, then this element is contained in the range from 1 to 1.5%.

X - chromium
N - nickel
K - cobalt
M - molybdenum
B tungsten
T - titanium
D - copper
G - manganese
C - silicon
F - vanadium
P - boron
A - nitrogen
B niobium
E - selenium
C - zirconium
U - aluminum

Chromium (Cr):

is the main element of steel, determining its resistance to oxidation (corrosion). Chromium sharply increases the corrosion resistance of steel when it increases in the alloy above 12.5%, starting from this concentration a dense oxide film of Cr2O3 is formed on the surface (chromium actually makes steel stainless, for example, steels 20Х13, 30Х13, 40Х13, etc.) ;
when the chromium content in steel is 12-14%, the thermal conductivity of steel is 2 times less than pure iron, and the electrical resistance increases 3 times;
provides increased strength at elevated temperatures, the addition of chromium increases the hardness and strength of steel without reducing its ductility;
reduces the impact strength of steel.

Nickel (Ni):

The main function of nickel is to stabilize the austenitic structure of steel; such a structure is especially strong and elastic. The minimum amount of nickel capable of stabilizing the austenitic structure is 8% (this is exactly how much nickel is found in the most common imported steel AISI 304);
the presence of 8-10% nickel in steel provides it with good ductility and good forming properties;
improves the weldability of steel and further increases the resistance of steel to oxidation (corrosion) in the weld area;
nickel increases the heat resistance of steel (especially in relation to resistance to deformation);
Thanks to nickel, stainless steel polishes better and is more scratch resistant than conventional steels (brushed and mirrored surfaces).

Molybdenum (Mo):

increases the resistance of steel to oxidation (corrosion) at high temperatures, reduces the resistance of steels to pitting corrosion;
increases red resistance, elasticity, tensile strength;
provides additional thermal strengthening.

Titanium (Ti):

increases the strength of steel;
Titanium is added to stainless steels to prevent intergranular corrosion.

Carbon (C):

with an increase in carbon to 0.8%, the hardness and strength of the steel increases, but leads to an increase in the threshold of cold brittleness (for example, steels 40Х13 and 95Х18 are used for the production of knives);
the more carbon there is in the steel, the more difficult it is to process by cutting, the worse it deforms and the worse it welds (for example, the most common commercially available imported steels of the 300 series AISI304/321/316 have 0.8% carbon in their composition, which gives them a wide range of applications compared to domestic steel 12x18n10t).

Compliance of foreign standards with Russian GOST.

Currently, almost all stainless steel products supplied to our country are marked according to AISI, DIN, or EN standards. Let's consider the compliance of these standards with Russian GOST.

AISI (American Iron and Steel Institute), American Institute of Iron and Steel

The designation of standard stainless steels according to AISI includes three numbers followed by one, two or more letters in some cases. The first digit of the designation determines the steel class.

Thus, the designations of austenitic stainless steels begin with the numbers 2XX and 3XX. While ferritic and martensitic steels are defined in class 4XX.

Moreover, the last two digits, unlike carbon and alloy steels, are in no way related to the chemical composition, but simply determine the serial number of the steel in the group.

The additional letters and numbers following the numbers used to designate AISI stainless steels mean:

xxxL – Low carbon content < 0.03%xxxS – Normal carbon content < 0.08%xxxN – Added nitrogenxxxLN – Low carbon content < 0.03% + added nitrogenxxxF – Increased sulfur and phosphorus contentxxxSe – Added seleniumxxxB – Added siliconxxxH – Extended range of carbon content

xxxCu – Copper added

For example:

Steel 304 belongs to the austenitic class, the carbon content in it is

Source: https://nergspb.ru/useful/

NICKEL

articles

NICKEL, Ni (niccolum), metal chemical element VIIIB of the subgroup of the periodic system of elements, member of the iron triad Fe, Co, Ni. Nickel was discovered by the Swedish chemist A. Kronstedt in 1751. It is widely known as a component of coin alloys with precious metals; It is also used in the technology of corrosion-resistant coatings obtained by electroplating.

The main nickel ores - nickel (kupfernickel) NiAs, millerite NiS, pentlandite (FeNi)9S8 - also contain arsenic, iron and sulfur; igneous pyrrhotite also contains pentlandite inclusions. Other ores from which Ni is also mined contain impurities of Co, Cu, Fe and Mg. Nickel is sometimes the main product of the refining process, but more often it is obtained as a by-product in other metal processes.

The world leader in nickel production is Russia, followed by Canada, Australia, Cuba, New Caledonia and Indonesia.

PROPERTIES OF NICKEL

PROPERTIES OF NICKEL
Atomic number	28
Atomic mass	58,69
Isotopes
stable	58, 60–62, 64
unstable	56, 57, 59, 63, 65, 66
Melting point, °C	1455
Boiling point, °C	2900
Density, g/cm3	8,90
Hardness (Mohs)	5,0–6,0
in the earth's crust, % (mass.)	0,008
Oxidation states	0, +2, +3, +4

Properties

Nickel is a silvery-white metal with a yellowish tint, very hard, tough and malleable, attracted by a magnet, exhibiting magnetic properties at temperatures below 340° C.

It is not highly chemically active and is stable in the atmosphere, water, alkalis and a number of acids, which is due to the tendency of nickel to passivate due to the formation of a surface oxide film that is resistant to corrosion. Nickel burns only in powder form. Forms two oxides NiO and Ni2O3 and, accordingly, two hydroxides Ni(OH)2 and Ni(OH)3.

The most important soluble nickel salts are acetate, chloride, nitrate and sulfate. Solutions are usually colored green, and anhydrous salts are yellow or brownish-yellow. Insoluble salts include oxalate and phosphate (green), three sulfides NiS (black), Ni2S3 (yellowish-bronze) and Ni3S4 (black).

Nickel also forms numerous coordination and complex compounds. For example, nickel dimethylglyoximate Ni(HC4H6N2O2)2, which gives a clear red color in acidic conditions, is widely used in qualitative analysis for the detection of nickel.