Kinds of stainless steel decoding. Corrosion resistant steel. steel grades: gost. stainless steel - price
In GOST, there is simply no such concept, therefore, in principle, there can be no single answer. When choosing a specific grade of stainless steel, it is necessary to take into account the basic requirements that apply to materials that are constantly in contact with food. What they consist of, what parameters of the metal to focus on and what to consider when choosing the “food grade” stainless steel brand - all this will become the subject of a detailed investigation.
The concept of "stainless steel" is a generalized one. This category includes steels such as martensitic, ferritic, austenitic, chromium-nickel and several others. Theoretically, they can all be used for transportation, food storage and cooking.
And what to do in practice?
What to look for
Corrosion rate
It is measured in mm / year. According to this parameter, all food steels are classified into groups: perfectly (0.0010), satisfactory (from 0.0011 to 0.003) and low resistance (not more than 0.005). This takes into account the peculiarity of the corrosion process, that is, the uniform distribution of inclusions throughout the area, their depth.
The specifics of using stainless steel
In principle, this paragraph is a continuation of the first. It is one thing to cook food in metal utensils, and another to use as a cutlery. In the latter case, its contact with food is short-term. The same applies to boxes (chests) for storage, pipelines, which are used as part of the technological chain at food industry enterprises.
Features of stainless steel care
It is understood how often and by what means it is processed. At home, cleaning products are used that are not classified as highly aggressive. Another thing is production. In principle, according to this characteristic, all stainless steel for domestic use is quite suitable.
The main brands of stainless steel and their brief description
In brackets - classification according to the Western AISI standard. All listed brands can be used in the food industry.
08X18H10 (304)
One of the inexpensive varieties of stainless steel. Such steel is well welded, polished (by electric means), characterized by sufficient strength at normal temperature. Use as utensils for heat treatment of products is not recommended.
03X17H14M2 (316)
It is characterized by high stability at high temperatures.
08X13 (409)
All characteristics are average. Such steel is more suitable for the manufacture of dishes and kitchen utensils.
12X13 (410)
A distinctive feature is heat resistance and increased resistance to corrosion. It can be used only in slightly aggressive environments.
20Х13 - 40Х13 (420)
Such steels have a wider range of applications. From kitchen sinks to utensils. Due to their high ductility, wear resistance, and almost complete inertness to corrosion, these grades are considered almost universal.
08X17 (430)
Another brand that, according to its characteristics - good heat conductivity, strength, ductility in processing and resistance to corrosion - is suitable for use in the manufacture of household appliances in which food is cooked by heat treatment. Including steam.
It remains to add that all of the listed stainless steel brands fully meet the requirements related to hygiene and toxicity of materials. Therefore, in products from them (various containers), you can store products, preservation, cook food without harm to health.
More detailed information on the specifics of using certain grades of stainless steels can be found in GOST No. 51687 of 2000 (washing); 5632 from 1972 (cutlery and accessories).
Wikipedia gives the following definition: “Stainless steel is a complex alloy steel (steel is an alloy of iron with carbon in which the latter (0.01-2%)), resistant to corrosion in the atmosphere and aggressive environments, containing at least 12% chromium”.
Thus, chromium is the main alloying element of stainless steel, determining its corrosion resistance. The higher the chromium content, the greater the corrosion resistance of steel. Corrosion is the process of metal destruction under the influence of the external environment. The flow mechanism distinguishes between chemical corrosion that occurs under the influence of gases and non-electrolytes (oil), and electrochemical corrosion that develops in the event of metal contact with electrolytes (acids, alkali, salts, moist atmosphere, soil, sea water).
Corrosion resistant (stainless) steel
Steels resistant to electrochemical corrosion are called corrosion-resistant (stainless) steels (chromium content 17% or more). The steel's resistance to corrosion is achieved by introducing elements into it that form dense, insoluble oxide films firmly bonded to the base, preventing direct contact with the external environment, and also increasing its electrochemical potential in this medium. The corrosion resistance of steel is also affected by the condition of its surface. If the surface of the polished steel does not have point defects, which can be concentrators of the corrosion process, the corrosion resistance of such a material is higher. For stainless steel, there is also the concept of intergranular corrosion (MCC). Intergranular corrosion is a phenomenon caused by the uneven (grain) structure of the metal, in which chromium carbides (Cr23C6) are actively formed at the grain boundary upon heating. In this case, chromium depletion of the main grain structure occurs below 12% of the threshold.
Especially prone to this phenomenon, hardened stainless steels having a high percentage of carbon and a minimum (13%) of chromium. The hardenability of steel directly depends on the percentage of carbon, the more carbon in the composition of the steel, the greater the hardness can be achieved by hardening, although to the detriment of ductility. If hardness and hardenability are not the main requirements for stainless steel, then they try to minimize the percentage of carbon, this reduces the tendency of steel to MCC. Another way to reduce the likelihood of MCC is to introduce strong carbide-forming elements, such as titanium and niobium, into the composition of the steel. In this case, instead of chromium carbides, carbides such as TiC and NbC are formed, and chromium remains in the solid solution, thereby preserving the anticorrosive properties of steel. To impart enhanced anti-corrosion properties and resistance to particularly aggressive environments, steel is additionally alloyed with molybdenum.
Stainless Steel Grades
Stainless steel in its structure is divided into three main classes:
- 1) martensitic stainless steels
- 2) ferritic stainless steels
- 3) austenitic stainless steels
Thus, the permanent magnet test will only help determine what class stainless steel belongs to, but in no way allows us to judge its quality.
Alloying elements
The main alloying elements determining the austenitic structure of steel are nickel and manganese. In addition, these elements also affect certain mechanical properties of stainless steels. Steel containing 17-18% chromium and 8-10% nickel in its composition have good ductility and the ability to deep draw during stamping. Recently, in connection with rising nickel prices, cheaper, so-called economically alloyed steels have been increasingly used, in which the percentage of nickel is reduced to 4-5%, and instead of expensive nickel, cheaper manganese is used (8-10%). To stabilize the structure of this type of steel, copper is added to it (1.5-2%). The disadvantage of economically alloyed steels is their tendency to crack formation during deep drawing. Moreover, the formation of cracks occurs in the direction of movement of the working tool both directly in the drawing process, and some time after that. The probability of cracking depends on the thickness of the material. The thinner the material (sheet), the greater the likelihood of such cracks.
Austenitic steels have good weldability. They give an almost perfect specular gloss for mechanical polishing. These steels are well polished by electrochemical and electrolyte-plasma polishing (EPP) methods, and the higher the nickel content, the better the result (improvement to 2 classes of surface cleanliness in one 3-minute cycle).
Nickel-free high-chromium (17-23% chromium) belong to the ferritic class of stainless corrosion-resistant steels. These steels are tougher than austenitic steels, and some of them are practically inferior in corrosion resistance to austenitic steels due to the introduction of niobium or titanium into the structure and a low carbon content. These steels have good deep drawing ability, good weldability, are much cheaper than austenitic chromium-nickel steels, but are less susceptible to mechanical polishing. EPP polishable, but they do not give perfect shine due to milky surface dullness. Nickel-free low-chromium steels (13% chromium), with a high carbon content (0.2-0.65% carbon) belong to the martensitic class. These steels have the ability to harden. In the hardened state they have high surface hardness (HRC 45-65). Due to the low chromium content, they are prone to MCC. The process of hardening of such steels is carried out in an inert gas environment in order to avoid chromium burnout and excessive carbide formation. To increase the anticorrosion properties and reduce the likelihood of the formation of MCC, such steels can be additionally alloyed with molybdenum and titanium. Martensitic steels are processed in a crude (non-hardened) state by forging and stamping. Mechanical polishing is done after hardening. Such steels are of little use for EPI polishing; in the working electrolyte solution for chromium-nickel steels, they become black and lose their luster.
Stainless steel marking
Stainless steel grades are standardized. There are several standards systems for stainless steels in the world. American AISI, Japanese JIS, European EN, German DIN, GOST in the CIS countries, etc.
Ilya N. Petunov © 2008
A lot of metal disappears annually due to corrosion. However, even more damage is caused by the failure of metal products as a result of corrosion. The costs required to replace parts or to repair equipment, automobiles, sea and river vessels, equipment used in chemical production are many times higher than the cost of the material that went into their manufacture.
Significant losses are indirect. These include, for example, the leakage of gas or oil from pipelines damaged by corrosion, spoilage of food, the destruction of building structures, and much more. Therefore, the fight against metal corrosion is of paramount importance.
Why is the destruction of metallic materials?
Before moving on to the question of what corrosion-resistant steel is, let's look at the concept of corrosion and the essence of this process.
Translated from the Latin corroder - erosion. Slow spontaneous destruction of metals and alloys based on them, occurring under the chemical influence of the environment, is called corrosion. The cause of this destruction is the chemical interaction (redox reactions) of metallic materials with the gaseous or liquid medium in which they are located.
What are corrosion resistant steels and alloys?
Products made of stainless and or their alloys are designed to operate in aggressive environments at high or normal temperatures. Therefore, the main requirement for the materials of this group is heat resistance (resistance to the action of a gaseous medium or steam of high temperatures) or corrosion resistance (the ability to effectively resist the effects of aggressive factors at ordinary temperature).
Corrosion resistance is inherent in metal products, on the surface of which in a hostile environment a strong passivating film is formed, which prevents the penetration of deeper layers of the metal and the interaction of aggressive substances with them.
In other words, corrosion-resistant steel is steel that is resistant to intergranular, chemical, electrochemical and other corrosion.
Chemical composition
The properties of a metal are determined by its chemical composition. With a chromium content of 12-13% stainless, that is, stable in the atmosphere and chemical environments. An increase in chromium content up to 28-30% makes it stable in aggressive environments.
Other elements used for alloying include manganese, aluminum, titanium, nickel. The most widely used alloys are those containing an average nickel content of 10%, chromium - 18%, carbon - from 0.08 or 0.12%, titanium - 1% (12X18H10T - corrosion-resistant steel, GOST 5632).
Microstructure classification: austenitic grade stainless steel
The corrosion resistance of this class increases due to the elements of alloying nickel (from 5 to 15%) and chromium (from 15 to 20%). Austenitic alloys are insensitive to intergranular corrosion, provided that the carbon content in them is lower than the solubility limit in austenite (0.02-0.03% or less). Non-magnetic, well welded, cold and hot deformation. They have excellent adaptability. This is the best steel for the manufacture of fasteners, welded structures and applications in various industries.
Martensitic class
Stainless steels included in the martensitic class can be magnetic and have higher - in comparison with austenitic - indicators of maximum hardness. Hardening is achieved by hardening and tempering. Well suited for the manufacture of products intended for use in medium and low intensity environments (for example, a number of food products or the manufacture of razor blades).
Ferrite class
With high corrosion resistance, the properties of these grades are similar to low carbon steel. The average chromium content is 11-17%. They are used in the manufacture of household appliances, elements of the architectural decor of the interior, kitchen utensils.
Austenitic-ferritic class
Corrosion-resistant stainless steels of this class are characterized by a reduced nickel content and a high chromium content (from 21 to 28%). Niobium, titanium, and copper act as additional alloying elements. After carrying out the ratio of ferrite and austenite is approximately one to one.
The strength of austenitic-ferritic steels exceeds austenitic twice. At the same time, they are ductile, withstand shock loads well, have a low level of corrosion cracking and high resistance to intergranular corrosion. Recommended for use in construction, manufacturing, for the manufacture of products that will be in contact with sea water.
Austenitic-martensitic class
Stainless steel: price (factors influencing the formation)
Corrosion resistant metals include expensive materials such as chromium, nickel, titanium, and molybdenum. Their value is crucial in pricing. Since other grades (carbon, structural, ball-bearing, tool, etc.) contain the listed elements in much smaller quantities, then the cost of corrosion-resistant steels is always higher in comparison with them. However, the price may vary depending on market conditions and the costs required for the production of stainless steel.
Mechanical properties
Grades of corrosion-resistant steels must have mechanical properties that meet the requirements of established manufacturing standards. These include:
- brinell maximum hardness (HB);
- relative extension (%);
- yield strength (N / mm 2);
- tensile strength (H / mm 2).
After production, each batch (smelting) of commercial products is checked for compliance with the mechanical properties and microstructure of the steel grade GOST. The results of laboratory testing of samples are indicated in the certificate of manufacture.
Steel grading system
An extensive range of alloys and steels is produced in various countries of the world. At the same time, there is still no unified international system for labeling them.
In the United States of America there are several signage systems. This situation, due to the large number of standardization organizations (AJS, ANSI, ACJ, SAE, AWS, ASTM, ASME), creates certain difficulties for partners, contractors and customers of metal products from American manufacturers from other countries.
In Japan, steel is marked with letters and numbers indicating their group (low alloy, high alloy, special alloys, medium alloy, high quality, high quality, etc.), its serial number and metal properties.
In the countries of designation, it is regulated by the standard EN 100 27, which determines the procedure according to which the name and serial number are assigned.
In the Russian Federation, an alphanumeric system developed during the Soviet Union operates, in accordance with which steel grades are indicated. GOST prescribes to indicate each alloying chemical element that is part of the metal, in capital Russian letters.
For manganese it is G, silicon - C, chromium - X, nickel - H, molybdenum - M, tungsten - B, vanadium - F, titanium - T, aluminum - Yu, niobium - B, cobalt - K, zirconium - C, boron - R.
The numbers following the letter indicate the percentage of alloying elements. If the composition of the steel contains less than 1% of the alloying element, then the figure is not put down, with a content of 1 to 2% after the letter they put 1. The two-digit number indicated at the beginning of the grade is necessary to indicate the average carbon content in hundredths of a percent within the brand composition.
Assortment of stainless steel products
Corrosion-resistant steel is used to produce the following products:
- heat-treated etched and polished sheets;
- heat-treated non-etched sheets;
- thermally untreated and non-etched sheets;
- warm, cold and hot deformed;
- hot-rolled steel strips for general purposes;
- calibrated hexagons;
- stainless circles;
- stainless wire (heat-treated and cold drawn);
- castings with special properties;
- forgings;
- other types for which GOSTs and technical instructions (TU) are developed.
Application area
Being one of the best examples of strength, aesthetics, resistance to the destructive force of corrosion and high temperatures, recyclability and long service life, possessing excellent surface treatment that meets all sanitary and hygienic requirements, corrosion-resistant steel is widely used in almost all areas of economic and economic activities.
The stainless steel is in high demand in the petrochemical, chemical, pulp and paper, food industries, in the construction industry, electric power, shipbuilding and transport engineering, in the areas of instrumentation and environmental protection.
The efficiency and durability of products made of stainless steel is determined by the correct choice of its class and brand, understanding of the physicochemical properties and structure of the microstructure. Using metals resistant to the damaging effects of corrosion, in strict accordance with their properties, we get the opportunity to take advantage of all the undeniable advantages of modern technology.
AISI200
Stainless steels, in which nickel is partially replaced by manganese and nitrogen to stabilize the austenitic structure, have established themselves as an effective substitute for standard chromium-nickel steels.
Application area:
It is used for the manufacture of metal utensils, household kitchen utensils and appliances.
AISI 304 (08 X18H10)
Austenitic, low carbon. Easy to weld, resistant to intergranular corrosion. High strength at low temperatures. It can be electropolished. It is the most versatile and widely used of all grades of stainless steels.
Application area:
It is used in installations for the food, chemical, textile, oil, pharmaceutical and paper industries.
AISI 310 (20 X23H18)
Refractory austenitic steel heat-resistant. In an oxidizing medium, usually up to 1100 ° С and up to 1000 ° С in a reducing medium can be used, but in any case in an atmosphere containing less than 2 g. sulfur (S) per 1 m³.
AISI 310S (10 X23H18)
It is a low carbon version of AISI 310 (20 X23H18) and is offered for use in environments where corrosion by high temperature gases or condensates is possible.
Application area:
In installations for heat treatment and during hydrogenation, as well as heat exchangers for furnaces; the manufacture of doors, pins, brackets, parts of plants for the conversion of methane, gas pipelines, combustion chambers. It can be used as a material for heating elements in the production of air heaters. And also, as a material for conveyor belts in conveyors of furnaces, exhaust pipes of gas turbines and motors.
AISI 316 (08 X17H13M2)
An improved version of AISI 304 (08 X18H10) (with the addition of molybdenum), which makes it especially resistant to corrosion. The technical properties of this steel at high temperatures are much better than that of similar molybdenum-free steels. (Molybdenum (Mo) makes steel more protected from pitting corrosion in chloride, seawater and acetic acid vapors).
AISI 316L (03 Х17Н13М2)
Steel similar to AISI 316 (08 X17H13M2) with a very low carbon content. Particularly suitable for the manufacture of welded structures. It has high resistance to intergranular corrosion; it is used in temperature conditions up to 450 ° C.
Application area:
AISI 316 (08 Х17Н13М2) and 316L (03 Х17Н13М2) are used for chemical equipment, instruments that come into contact with sea water and the atmosphere, in the manufacture of equipment for the development of photographic films, in food processing plants, and containers for used oils.
AISI 316Ti (08 Х17Н13М2Т)
The presence of titanium (Ti), five times the carbon content, provides a stabilizing effect in relation to the deposition of chromium carbides (Cr) on the surface of the crystals.
Application area:
Parts with high resistance to high temperatures and to the environment with the presence of new chlorine ions. Blades for gas turbines, cylinders, welded structures, manifolds. Also used in food and chemical industries.
AISI 321 (08 X18H12T)
Nickel-chromium steel with the addition of titanium (Ti) is especially recommended in the manufacture of welded structures and for use at temperatures between 400 ° C and 800 ° C. It is steady against corrosion.
Application area:
Equipment for the oil refining industry, chemical equipment and equipment resistant to high temperatures. It is also used for the manufacture of welded equipment in various industries (pipes, furnace fittings, heat exchangers, muffles, retorts, nozzles and exhaust manifolds).
AISI 409 (08 X13)
Low carbon content, high oxidation resistance and workability.
Application area:
Exhaust pipes, manifolds, converter housings.
AISI 410 (10X13)
Base martensitic stainless steel. It has high impact strength, good corrosion resistance and heat resistance.
Application area:
It is successfully used in products exposed to slightly aggressive environments (precipitation, aqueous solutions of salts of organic acids) at room temperature. Steel type AISI 410 (10X13) can be used in the manufacture of machine parts and apparatus for the wine industry. These steels are allowed to be used in direct contact with wort, brandy alcohol, and waste products from the food industry.
AISI 420 (20X13)
Martensitic stainless steel, has high wear resistance, ductility, resistant to high temperatures and corrosion. Compared to the basic martensitic grade AISI 410 (10X13), AISI 420 (20X13) steel, having a high carbon content, has higher hardness and wear resistance.
Application area:
It is used in cases where a combination of high strength and good corrosion resistance is required. Namely:
· Cutting, measuring tools, springs, carburetor needles, piston compressor drains, parts of internal devices and other various parts working for wear in slightly aggressive environments up to 450 ° С;
· Details of turbines and boilers;
· Thermal and separation screens, filters.
AISI 420 (20X13) steel can be used for the manufacture of technological equipment used at various stages of food production (washing or hygienic processing of raw materials, grinding, separation and sorting of products, mixing, heat treatment).
AISI 430 (12X17)
These are the most widely used ferritic chromium steels. They have good strength and mechanical characteristics, which is ensured by a high chromium content and a low carbon content; well deformed, used in the processes of drawing and stamping. Unlike austenitic nickel-containing steels, low-carbon chromium ferritic steels are resistant to corrosion processes in various sulfur-containing environments. Therefore, AISI 430 (12X17) steel products can be used in systems for pumping gas, oil and pure oil products. Structures from AISI 430 (12X17) are less resized by temperature fluctuations.
Application area:
Due to the low coefficient of thermal expansion, steel is optimal for products experiencing temperature changes, and high thermal conductivity determines the advantages of using this steel in heat transfer systems. With a relatively low thermal inertia (specific heat), AISI 430 (12X17) steel, with lower energy consumption, warms up and cools faster, which avoids possible overheating during the preparation of food products.
AISI 439 (08 X17T)
Excellent corrosion resistance in vehicle exhaust gas condensate.
Application area:
It is used in the manufacture of automobile silencers, the manufacture and decoration of elevators and escalators, kitchen equipment.
- 3.1.1. For running ladders 3.1.2. For well stairs 3.1.3. For marching stairs
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How to choose a stainless steel brand?
March 24, 2015
Choosing a steel grade is a complex process and requires special qualifications, as well as reliable information about the facility and the conditions for using the railing. Only an expert can make an informed decision. It is best to contact our specialists and they will make you an expert recommendation on the grade of steel for your fences (as well as on the type of surface treatment).
For indoor and outdoor railings - Prima AISI201 steel or cheaper AISI201 steel is usually recommended. Provided that the room is heated and normal humidity.
For railings on the street, for example, for out-of-town game or cottage - use Super AISI304L steel or cheaper AISI304. Provided that the railing will not stand within the TTK and not near the sea, lake or river.
For objects inside the TTK, for houses in the vicinity of water bodies, for a pool, a summer residence or on a balcony / roof. almost always recommend Ultra AISI316L.
Corrosion is the process of metal destruction under the influence of the external environment. Corrosion resistance is provided by a film of chromium oxides formed on the surface of the metal when it interacts with atmospheric oxygen and is able to self-repair after damage. The higher the chromium content, the greater the corrosion resistance of steel. The flow mechanism distinguishes between chemical (under the influence of flue gases and non-electrolytes: oil) and electrochemical (metal contact with electrolytes: acids, alkali, salts, humid atmosphere, soil, sea water).
Steels resistant to electrochemical corrosion are called austenitic corrosion-resistant (stainless) steels: chromium content from 17%. The steel's resistance to corrosion is achieved by introducing elements into it that form dense, insoluble oxide films firmly bonded to the base, preventing direct contact with the external environment, and also increasing its electrochemical potential in this medium.
The corrosion resistance of steel is also affected by the condition of its surface. If the surface of the steel is polished and does not have point defects - cracks, which can be concentrators of the corrosion process, then the corrosion resistance of such a material is higher. Therefore, the corrosion resistance of polished steel is much lower than polished analogues. A well-polished stainless steel will better resist corrosion than a poorly polished counterpart.
In the manufacture of stainless steel railings and railings, RailingsGlavSnab uses the following grades of stainless steel: AISI 201, AISI 201 (PRIMA), AISI 304, AISI 304L (SUPER trademark), AISI 316L (Ultra trademark).
Stainless steel for indoor use
brands Prima AISI 201 and AISI 201
When designing metal fences that will be used indoors, we use AISI 201 Prima or AISI 201 steel. The most important advantage of 201 steel fences is their low cost, 30-50% less than thataISI 304 steels .
At the same time, stainless steel railings of AISI 201 grade have good anti-corrosion properties under normal conditions, ...
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if these fences are installed indoors with constant moderate humidity. And do not have contact with aggressive and oxidizing environments. At the same time, it is worth remembering that fences require regular maintenance with protective pastes of the type (Our managers will select the most suitable protective pastes for your fencing. When buying fences, paste is a gift.) In the case of the use of such fences in a more aggressive environment, for example, in a country house, basement, or regular wet cleaning, we recommend the use of steel grades of the PRIMA family. The chemical composition of this steel is 74% more resistant to aggressive environments, due to the increased amount of alloying additives Nickel (Ni) and Chromium (Cr). In PRIMA steels, the use of secondary raw materials is not allowed, a different melting temperature is observed, in this regard, the amount of carbon (C), phosphorus, sulfur and other indicators of recyclables is much lower than the lower limits allowed by the AISI 201 standard. Using a Prima pipe such steel will add 3-5% of the cost of the finished product, but the finished metal structure will be with completely different qualities, the service life of such a product will be twice as long as AISI 201. |
Stainless steel for railing outside or for wet rooms.
AISI 304 and AISI 304L (Super Brand)
If stainless fences will be installed on the street, but away from large roads or in rooms with high humidity, but without contact with water, for example, in dry parts of pools, baths or bathtubs, then a stainless steel of the AISI 304 family should be used.
The railing made from this brand of stainless steel is more resistant to corrosion than the AISI 201 family. Improved corrosion resistance is associated ...
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with increased (5 times), compared with the brand AISI 201, the content of nickel and chromium in the composition of steel. AISI 304 stainless steel guards and railings work perfectly in conditions of variable humidity and in contact with saturated water vapor. The possibility of using this steel in the external environment is its main advantage over AISI 201. Our assortment includes both standard AISI 304 stainless steel pipe for the market and improved 304th steel, Super or AISI 304L grade. This steel is used in everyday life as a food stainless steel and cutlery is made from it. In medicine, for example, scalpels are made of it. It has a slight, but very important difference in chemical composition from AISI 304:
Products made from the Super steel grade can last 245% longer in an aggressive environment without the slightest sign of corrosion. In life, this means polishing, wiping and caring for fences three times less often, being calm for your reputation for many years. |
Stainless steel for objects inside the TTK or near the sea,
pools and baths. AISI 316 and AISI 316L.
Corrosion-proof railings at objects in the TTK zone, such as handrails, ramps, flow dividers or entry groups, as well as fences for pools or baths made of AISI 316 steel, perfectly resist corrosion in an environment with increased aggressiveness. AISI 316 steel fencing does not rust for many years when used in places with ...
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constant contact with reagents and road suspension. A modern big city is a great place to use such steel. Under the conditions of modern megacities, when the environment is heavily polluted by car exhaust, chemicals that enter the environment actively react with atmospheric water vapor, forming acids and alkalis. In addition to substances from exhaust gases, active substances from the anti-icing compound that process roads in the winter period fall into the atmosphere of the city. As a result, precipitation occurs with increased oxidizing properties. In fact, this is already a weak acid solution. In such conditions, the AISI 304 steel commonly used for outdoor fencing does not withstand and corrodes in one autumn-spring season. This problem, first of all, was encountered by our European colleagues in the eighties. Solving the problem of extending the service life of stainless steel outdoor structures, European specialists began to use, in urban conditions, only the AISI 316 steel family. And in the city center and at especially important facilities, steel grades of type 2205 are added. Such steel grades contain manganese and molybdenum in addition to nickel and chrome , which greatly increases resistance to any acids and alkalis used in everyday life. Handrails for public pools are also made from AISI 316 stainless steel. Corrosion-proof handrails for pools are constantly in contact with highly chlorinated water. Such water is a very strong oxidizing agent and only AISI 316 stainless steel railings can last for a long time in such conditions. When arranging embankments or observation platforms by the sea, PerilaGlavSnab uses AISI 316 steel for fencing, as the sea air is saturated with actively oxidizing substances. Fortunately, AISI 316 steels cannot be smelted in “artisanal conditions”, we have not yet encountered fakes and it is now very rare to find a clean version of AISI 316, usually all steel becomes AISI 316L after smelting. The use of the AISI 316L steel grade, in comparison with AISI 304, increases the project budget by 40%, in comparison with the 201st steel it adds 70% to the total cost. This is an insignificant supplement for restful sleep after working at critical facilities. |