There are hardly any people who doubt that there is nothing stronger than metal, especially if it belongs to the stainless group. But such a statement is very generalized because stainless steel can have different forms, wall thickness, etc. Stainless pipe 6x1, 10x0.5 can be bent by hand without much effort. In general, stainless steel is endowed with a lot of advantages. Even the name indicates that this one does not rust and is indestructible, it is durable and aesthetic. The presence in it of a certain amount of chromium, nickel, and other elements makes the metal stable in conditions sea ​​water, acid, oil, chloride medium.

grouping

The industry offers stainless steel, the grades of which belong to the following groups:

• austenitic (chromium 15-26%; 5-25% nickel, molybdenum 2-6%);
• ferritic (carbon 0.2%; chromium 12-27%);
• duplex (mixed ferritic-austenitic structure with the inclusion of 18% - 28% chromium and 4.5% - 8% nickel);
• martensitic (chromium 10-13%; carbon 0.2-1.0%).

The most popular are ferritic (AISI 430; AISI 201) and austenitic (AISI 304, AISI 321, AISI316, AISI 316T) groups. They are not taken on a magnet and have a wide range of applications. Stainless steel of the martensitic group has certain useful properties, but is taken on a magnet. It is most often used in industry, excluding the use in the field related to food and beverages.

Stainless steel grades 12 X18H10T and 08X18H10T

In Russia, more and more brands of stainless steel are called European AISI names with three digits. But along with this name, the Soviet GOST is also used, which indicates the percentage of carbon, chromium, nickel, etc. Stainless steel 08x18n10t consists of a chromium-nickel alloy with the composition:

• carbon(C)-0.8%;
• chromium (X) - 18%;
• nickel (N) -10%;
• titanium (T) -1%.

Stainless steel 12X18H10T is identical to steel 08x18n10t and consists of:

• carbon(C)-12%;
• chromium-(X) 18%;
• nickel(N)-10%;
• titanium (T) -1%.

Marks 12 Х18Н10Т; 08X18H10T - the most popular, they correspond to the European name AISI 321, AISI 304. This stainless steel belongs to the austenitic group and has the following properties:

• sustainability;
• strength;
• durability;
• aesthetics.

This stainless steel is also called food and is widely used in medicine, food and alcohol industries. Many details of machine tool building, mechanical engineering are also made of steel 12X18H10T; 08X18H10T, due to design requirements. Do not refuse food stainless steel in oil production and processing. Stainless steel of this class can be easily processed, welded, polished. Cut stainless steel on special saws or plasma.

Heat resistant stainless steel

Many consumers think that if their product consists of stainless steel, then it is not afraid of anything. This is partly true, but not entirely. The use of conventional stainless steel on a thermal, in hot shops will lead to its destruction. In conditions of especially elevated temperatures, a special heat-resistant stainless steel is used, which is endowed with resistance to temperatures above 1000 degrees. Such alloys must contain no less than 17% chromium and a certain amount of nickel and other constituents. Heat-resistant stainless steel is 20X23H18 (AISI 310), 10X23H18 (AISI 310S), 20X20H14C2 (AISI 309), 20X25H20C2 (AISI 314), 95X18, etc. It is used in combustion chambers, suspensions, clamps, fasteners for boilers, baskets for thermal furnaces etc.

Range

The range of produced stainless steel is extremely wide. It can be equated to black rolled products with the exception of beams, strips, channels, pipes with a large diameter.
Popular stainless steel

• thin sheets;
• circles;
• squares, hexagons, corners.

Our warehouse in Moscow offers a wide range of products from heat resistant steel various brands. The high quality of the sold products is confirmed by manufacturers' certificates and meets the requirements of international standards. Domestic brands of heat-resistant stainless steel in our catalog include: 08X13, 08X17, 08X18T1, 10X23H18, 12X13, 12X17, 14X17H2, 20X23H18, 20X13, 30X13 and 40X13. Among foreign analogues, AISI 310, AISI 310S and AISI 321 steels should be noted.

Sizes and cost of goods are constantly updated, so please contact our managers to quickly and correctly place your order.

Definition and types of heat resistant

Heat-resistant stainless steel is an alloy that, due to its physical and chemical properties, is resistant to aggressive chemical substances and mechanical wear at temperatures above 500 °C. Such high performance properties are achieved due to the inclusion of a large number of alloying elements in the composition of the material. Chrome, nickel, titanium contribute to hardening crystal lattice metal and prevent the active spread of oxidation processes. Heat-resistant material does not undergo plastic deformation when high temperatures, does not form rust and scale.

The division of heat-resistant stainless steel into types is due to the different content of alloying elements, the difference in alloying methods, and the final purpose of the steel. There are 4 groups of stainless heat-resistant alloys:

• austenitic with chromium content up to 26%, nickel up to 25%, molybdenum up to 6%;
• ferritic, which contain no more than 0.2% carbon and up to 27% chromium;
• ferritic-austenitic (mixed, or duplex) steels with the inclusion of 18-28% chromium and up to 8% nickel;
• martensitic contain chromium 10-13% and carbon no more than 1%.

Heat resistant stainless steel grades

The main grades of heat-resistant stainless steels produced by the domestic and foreign metallurgical industry include:

• 20Kh20N14S2, also known under the name EI211 (import analogue of AISI 309) - a type of high-alloy chromium-nickel alloy containing chromium and nickel up to 22% and 15%, respectively;
• 20X23H18 or EI417 (analogue of Western European and American manufacturers AISI 310) - austenitic refractory steel, products from which are used in a reducing environment with temperatures up to 1000 ° C and oxidizing operating conditions up to 1100 ° C;
• 10X23H18 or EI417 (AISI 310S) - a low-carbon modification of the AISI 310 alloy, the need to use which is due to the presence of a corrosive environment due to the influence of condensates and high-temperature gases;
• 20Kh25N20S2 or EI283 (an analogue of foreign steel under the AISI 314 brand) is a non-magnetic, non-hardenable, austenitic alloy resistant to ultrahigh temperatures.

Application of heat resistant stainless steels

The use of heat-resistant alloys of a particular brand is due to the characteristics of the operating environment, loads:

• 20Х20Н14С2 (AISI 309) - parts and assemblies of thermal furnaces, conveyors, carburizing boxes are made from steel of this grade;
• 20X23H18 (AISI 310) is used for the manufacture of parts for conveyor belts of furnace conveyors, heat treatment plants, fuel combustion chambers (including internal combustion engines), motors, gas turbines, doors;
• 10X23H18 (AISI 310S) is mainly used in mechanisms, installations and units for transporting hot gases - turbines, methane conversion apparatus, exhaust systems, gas pipelines high pressure, heating elements;
• 20Х25Н20С2 (AISI 314) is used in the construction of furnaces - metal products from stainless heat-resistant steel of this grade are used for the manufacture of furnace screens, rollers, boiler hangers.

Welding features

Modern welding methods make it possible to obtain durable welds, resistant to hot cracking on parts made of heat-resistant stainless steels. However, alloys of this type are prone to softening and fracture of the cold weld. To eliminate the disadvantage, general or local heating of the material is carried out in order to minimize the temperature difference at the periphery and at the welding points to reduce stress. After welding, finished products are tempered for several hours at temperatures up to 2000 °C. As a result of tempering, the main part of the hydrogen dissolved in the structure is removed, and the residual austenite is transformed into martensite.

The development of energy and gas turbine technology is characterized by a continuous increase in the operating temperatures of parts and products. In power and transport installations, they have reached - up to 1100C and above. Such an increase in the operating temperature became possible due to the intensive development of a new class of metallic materials - heat-resistant and heat-resistant steels and alloys. These materials are able to work for a long time at high temperatures in a complexly stressed state with simultaneous exposure to an aggressive external environment and retain their physical and mechanical properties.

The complexity of modern technological solutions necessitates the use of materials with high technological properties.

For example, in the manufacture of blades for gas turbine engines, operations such as forging or precision stamping, machining of bars and finished products, grinding, polishing, and precision casting are used. In the manufacture of combustion chambers from heat-resistant sheet materials, cold stamping, pressing, bending, spot welding, rivet. This entire range of technological properties should be inherent in the metal used.

In accordance with the classification of materials for their intended purpose, heat-resistant (scale-resistant) steels and alloys are called that are resistant to gas corrosion at temperatures above 550C and operate in a lightly loaded state.

Consider one of the most common and used steels - 20X23H18. It belongs to heat-resistant steels. Manufactured in accordance with GOST 5632-72. Foreign analogue is AISI 310S steel.

Heat-resistant steel 20X23H18 is a consonant steel of this class used in domestic engineering. The basis of this steel, as well as all heat-resistant materials used in high-temperature installations up to 1350C, is iron and nickel. The high resistance to oxidation of steel is primarily due to the large amount of chromium, which is also part of the steel. In general, tests on heat resistant steels have shown that less than 14% Cr does not significantly improve heat resistance. The critical lower limit is somewhere around 14%; above this, chromium significantly increases the heat resistance. Its influence is especially pronounced in the range of 15-23%. However, it is not possible to increase the temperature limit of the operation of nickel and iron alloys by further increasing the chromium content. The fact is that with an increase in the chromium content above 30%, the melting point of iron and nickel alloys noticeably decreases, but the main thing is that the alloys become non-technological in metallurgical production. In general, the whole theory of alloying nickel heat-resistant steels is based on the study of the influence of other alloying elements on the Cr-Ni base.

The presence of carbon in steel 20X23H18 is limited to 0.2% (by weight). An increase in the carbon content leads to the fact that the heat resistance of the Cr-Ni alloy decreases due to the binding of chromium into carbides and the depletion of the solid solution in chromium.

Consider the main operational and technological properties of steel 20X23H18:

1. Steel is smelted in open arc furnaces.
2. Deformation temperature - the beginning of 1180, the end is above 900C, cooling after deformation in air.
3. Recommended heat treatment modes:
   a) heating 1100 - 1150C, cooling in air, in oil or water;
   b) heating up to 1160 - 1180C, cooling in water, aging at 800C, holding for 4-5 hours.
4. Steel is welded by TsT-19 electrodes.

Since heat-resistant alloys based on iron and nickel do not undergo phase transformations, heat treatment for them consists in high-temperature heating to grow grains of a certain size or to relieve internal stresses.

One of the important issues in the development of heat-resistant steels are economic issues. The profitability of steel is determined by three main indicators: economical alloying, manufacturability in the process of metal processing and the yield of suitable products, and the level of operational characteristics. Heat-resistant steel 20X23H18 (AISI 310S) is highly adaptable, has increased heat resistance and ductility, and is well welded. This steel embodies the most optimal ratios alloying elements.

Due to the high technological and economic performance of this steel, it has received the widest application in industry, since it can operate under conditions of a complex stress state, characterized by a constant change in the magnitude and sign of loads, and has high resistance to fatigue and corrosion at high temperatures.

Here short description areas of application of heat-resistant steel : working and guide blades, forgings and bandages operating at temperatures of 650-700C, parts of combustion chambers and other furnace equipment operating at temperatures of 1000-1150C, etc.

Flat and long products from steel 20X23H18 - the main warehouse item of the company "AVERS-Special Steels" are shipped instantly from a warehouse in Moscow or with a slight delay caused by the transportation of goods from regional warehouses.

2014-11-24 30 283

Home-made sauna stoves cost an average of 3-5 times cheaper than factory products. The savings will be even greater if the welding work is carried out independently. When making your own, you will need to decide on the following:

1. What metal to make a stove for a bath.
2. What thickness of the metal will be optimal.
3. What type of electrodes should be used to provide maximum strength weld.

The answer to all these questions depends on the speed of heating the steam room, the duration and intensity of operation of a self-made furnace.

Which brand of steel is better for a sauna stove

The flue gas heating temperature inside the furnace reaches 450-550°C. When heated at this intensity, deformation of the metal is observed.

The direct impact of fire leads to burning steel. Of course, you can simply use metal with a thickness of 10 mm or more, but then you have to heat the steam room for a long time, spend a large amount of fuel to warm it up. Due to the use of thick-walled steel sheets, a durable furnace will become uneconomical.

The task facing the master is to make the structure strong enough to prevent deformation, burnout and at the same time have good thermal conductivity. In the factory, for the manufacture of sauna stoves, metal with a high degree heat resistance.

Most manufacturers use AISI 430 chromium corrosion-resistant stainless steel. In budget models, iron for sauna stoves is changed to GOST 1050-88 structural steel. Each metal has its pros and cons.

Alloy steel differs from structural steel in the following characteristics:

Chromium-containing heat-resistant steel is expensive, and not all components experience the same thermal and corrosion stress. For this reason, the design of the sauna stove is made of several metals:

• Firebox - AISI 430 or analogue 08X17T is used for the combustion chamber. In self-production, steel 10 GOST 1050-88 is used.
• Screen - convection channels do not experience the same load as the firebox, therefore, for their production they take 08PS or 08Yu GOST 19904-90.
• The body of the stove for a bath is made of sheet structural steel.
• The door of the combustion chamber - practice shows that this part of the device experiences the maximum thermal load. For this reason, using even high-alloy stainless steel is not enough. After several fireboxes, deformation of the doors is observed. The best solution is to hang a cast-iron door.

As a rule, in the independent manufacture of a bath stove, metal is used, which is easier to machine and weld.

Optimum metal thickness for a furnace in a bath

When determining the thickness of the metal, two main characteristics are taken into account that affect the operating parameters of the bath furnace:

• Burnout of steel - if you use a thin-walled sheet of ordinary metal for the furnace, after literally six months of the furnace, you will have to repair the furnace. Ordinary steel with a thickness of 4 mm will provide a quick heating of the steam room, but will not last long. For this reason, manufacturers make the combustion chamber from AISI 430, a heat-resistant chromium-plated stainless steel 4-6 mm thick.
• Thermal conductivity - the heating temperature of the furnace directly depends on the thickness of the walls of the furnace. It seems that it was easier to make a combustion chamber from metal 10 mm or more, and so prevent burnout, but this approach is not practical for several reasons.
  The thicker the metal, the more thermal energy and time is required to warm it up and maintain the required temperature. Furnace equipment becomes economically unprofitable. The optimal thickness of the metal in the sauna stove should be 6-8 mm.

The minimum thickness of steel in the combustion chamber is 4 mm, it is permissible only if AISI 430 and 08X17T are used. In other cases, a metal thickness of at least 6 mm is required. Most craftsmen recommend using 8 mm thick structural steel when making the furnace yourself.