How to determine the category of steel c345

Steel C345, low-alloy carbon, high-strength manganese

C345 steel is produced mainly in sheets, which are used for the construction of building structures. This alloy is also used to make channels used for the construction of frames, vertical structures, columns, to increase the rigidity of floors, and in the construction of hangars and supports. High demand is also observed for metal corners, intended both for strengthening and for decorating a building. Good density and lightness, combined with an affordable price, have increased the popularity of this steel.

Steel welding can be carried out without preheating and heat treatment. The seams will be very tight and will be able to withstand serious external influences. All such items must comply with the rules of GOST, from which you can also find out a detailed description and options for this rolled metal. It should be noted that the following rules apply to the 345 model:

• the addition of aluminum and titanium is allowed;
• at the request of the consumer, 0.030% phosphorus and 0.035% sulfur can be added;
• analysis for the presence of chromium, nickel, arsenic and copper is allowed;

The manufacturing plant is obliged to strictly comply with all state requirements, and the products must apply the appropriate markings to the rental.

Use of steel 17G1S

The durability of the finished steel allows it to be used in a wide variety of areas. However, the main direction is the production of industrial parts, which include bends, flanges, splitters and other elements of pipelines and highways.

Since the bulk of these objects are underground, strong pressure and temperature changes are exerted on their surface

Therefore, it is important to choose an item that can withstand these factors without problems for many decades. If necessary, you can choose any foreign analogue of the 17G1S model: Fe510D1 (Germany), SM490A (Japan), 350W (Canada), Fe52CFN (European Union), 16Mn (China) and many others

Alternative options are almost identical in characteristics, and have no restrictions for welded structures.

Pipeline outlet made of steel 17G1S

Character traits

When C345 is exposed to a temperature of 20 °C, the steel is endowed with a short-term strength of 490 MPa, a fluidity of 345 MPa and an elongation at break of 15%. And the thicker the alloy, the lower these indicators will be. However, the elongation will increase to 21%. Rolled metal itself can be produced in 4 classifications, each of which has certain test indications: 1st and 3rd have impact strength at T = -40 °C, but at T = -70 °C such properties disappear. The 2nd and 4th categories are endowed with opposite indicators. As for viscosity after mechanical aging, they can only be observed in grades 4 and 3 of steel.

Properties of steel C345

Such characteristics make it possible to produce complex building structures that can withstand extreme loads. The lowest alloy ingot can be used to make fences and enclosures of any size, water pipes for various liquids, tanks for storing emulsions and other products for typical applications. Also, due to its resistance to aggressive factors, steel is often used in mechanical engineering to create elements of cranes, rails, and power line supports.

Steel for building structures C235 - characteristics, properties, analogues

This page shows the technical, mechanical and other properties, as well as the characteristics of steel grade C235.

Classification of material and application of grade C235

Grade: C235 Material classification: Steel for building structures Application: production of rolled products intended for building steel structures with welded and other connections

Explanation of symbols, abbreviations, parameters

Please note that this information about the C235 brand is provided for informational purposes. Parameters, properties and composition of real material grade C235 may differ from the values ​​​​given on this page

More detailed information about the C235 grade can be found on the information resource “Brand of Steel and Alloys”. You can check with our managers for information about the availability, delivery times and cost of materials. If you find inaccuracies in the description of materials or errors found, please inform the site administrators using the feedback form. Thanks in advance for your cooperation!

Chemical elements and manufacturing technology

Each spare part contains many chemical components, the proportions of which will determine the quality of the future workpiece. If we talk about C345, then it includes 10 components, each of which plays an important role:

• Carbon (C) – no more than 0.15. It is added to any low-alloy ingot to increase strength. This effect occurs due to the release of carbides; however, an increase in hardness negatively affects the ductility and weldability of the object.
• Silicon (Si) – up to 0.8%. It is the main deoxidizing agent, the content of which will determine the quality of the finished product. Si also provides better hardenability of objects.
• Manganese (Mn) – 1.3-1.7%. It is added to the joint of almost any ingot to remove oxygen. Its properties have a beneficial effect on the future weldability of parts.
• Nickel (Ni), Chromium (Cr), Copper (Cu) – about 0.3%. These three elements protect the plane from rust and increase the elasticity of the metal as the thermal state increases.
• sulfur (S) – 0.04%. It has a negative effect on weldability, but this component is necessary for further mechanized finishing.
• Phosphorus (P) – 0.035%. Reduces ductility, but increases resistance to brittleness at low temperatures.
• Nitrogen (N) – 0.012%. Increases resistance to scale, and is mixed into heat-resistant workpieces.
• Iron (Fe) – 96%. The main component.

Equal-flange steel angle C345

All components are added during further melting. At the first stage, the recycled iron is collected in a large container, where it is heated to extreme temperatures and kept for several hours. Then the substance goes into a molten state, and additional components float to the surface. The result is steel without impurities. And at the last stage, the hot iron is poured into another tank, where it is cooled and given new compounds.

General characteristics of the material

Any product has mechanical and physical properties that are determined during various tests. Knowledge of these indicators is a necessary condition, without which it is impossible to use the product correctly.

Properties of steel 17G1S

The characteristics of 17G1S steel are presented as follows:

• short-term strength limit – 490-510 MPa;
• maximum fluidity – 343-355 MPa;
• elongation at break – 20-23%;
• impact strength – 390-440 kJ/m2.

These indicators were obtained at T=20 °C and refer to sheet and pipe metal products.

It is important for metallurgical enterprises to produce high-quality products that meet the above criteria. To properly regulate this process, created objects are checked for compliance with state standards

The 17G1S steel itself belongs to GOST 19282-73, 19903-74, 5520-79 and 82-70.

These subparagraphs indicate all product indices, as well as the chemical composition of the steel, which, in this case, looks like this:

• “C” (carbon) – 0.15-0.2%. The substance is added to increase the density of the workpiece.
• “Si” (silicon) – 0.4-0.6%. Designed for hardening.
• “Mn” (manganese) – 1.15-1.6%. Removes excess oxygen.
• “Ni” (nickel), “Cu” (copper), “Cr” (chrome) – no more than 0.3%. The elements protect the plane from corrosion and protect it from the formation of cracks during loads.
• “S” (sulfur) – 0.04%. Improves the properties of future processing.
• “P” (phosphorus) – 0.035%. Increases the durability of an item.
• “N” (nitrogen) – 0.008%. Eliminates the alloy's tendency to age and increases its hardness.
• “As” (arsenic) – no more than 0.08%. Gives minor resistance to rust, and this amount does not make the steel harmful.
• “Fe” (iron) – 96%. The main component, without which it is impossible to create any iron part.

Rolled steel 17G1S

The above components must strictly correspond to the declared ones. Any, even minor, deviation can have a detrimental effect on the workpiece, which completely precludes its further sale.

Symbol meaning and classification

The name of any product contains important characteristics. And if we consider this variety, then its decoding has the following meaning: The symbol “C” says that the object belongs to the construction category. The following figures indicate the turnover of rental products. That is, the maximum stress at which plastic deformation of this material begins to appear reaches 345 MPa.

Floor beam C345

Steel grade C345 is mainly produced in accordance with GOST 27772-2015, and can be in the form of sheets, bent profiles, wide-band and shaped types. Rolled metal products belonging to this standard can have a wide range of applications. In some cases, compaction by heat treatment and the addition of impurities from other models are allowed. But all manufacturing methods must be discussed in advance with the customer, and the corresponding mark must be placed in the documents. In this case, the buyer will be provided with a quality guarantee.

Technical characteristics: subtleties of using reference manuals

The properties of 09g2s steel are largely determined by the chemical composition of the alloy, its specific parameters, which today are quite accurately calculated by metallurgists.

Steel grade 09g2s has the following critical points:

• Ac1 = 732, when austenite transforms into pearlite during cooling processes;
• Ac3(Acm) = 870 (s – from French chauffage/heating) the end point of cementite dissolution;
• Ar3(Arcm) = 854 (refroidissement – ​​cooling) the beginning of the release of Fe3C;
• Ar1 = 680 hypoeutectoid steel, corresponds to ferrite precipitation

The symbols are classic, numbers 1 and 3 indicate the numbers of points on the graph. The symbols cm usually mark hypereutectoid steels.

If we talk about other features of St 09g2s, the following characteristics are noted: easy weldability of the material. For this purpose, RDS, ADS under flux and gas protection are used. Only products that have undergone chemical-thermal treatment cannot be welded.

The mechanical properties of steel 09g2s are tabular values ​​that were developed by a number of GOST standards and describe the material at room temperature, as well as for its other states.

Among the important mechanical properties of 09g2s steel are the following:

• Yield strength for permanent deformation, measured in MPa;
• Relative values ​​of elongation at break and contraction;
• Impact strength (use under load is one of the main applications);
• Brinell hardness (HB).

Strength class of steel 09g2s: the table for the list of grades includes the one indicated, which, as already noted, corresponds to C345. This also includes a number of other brands. Thus, steels that are different in chemical composition and even in the method of producing steel can have the same strength class. This data can be found for 09g2s according to GOST 19281-2014; the characteristics of the alloys are presented in convenient tables that are easy to navigate. You can view (download) GOST 19281-2014 here.

But the opposite situation is also possible. For example, for 09g2s GOST 19281-89 and grade 16GS there is data on strength classes 265 and 296.

The same GOST describes the types of rolled metal:

• Varietal, round, shaped with various sections (including circle 09g2s).
• Wideband profiles with a certain thickness of products.

Large diameter circles steel 09g2s

Similar information is provided for other brands.

The density of steel 09g2s fluctuates, somewhere around the 7800 kg/m3 mark. But alloying elements can either increase the specific gravity or reduce it. Tungsten tends to be the first. The second is achieved by adding: cobalt, nickel, copper.

The hardness of steel 09g2s can be determined by Brinell, Rockwell, Vickers, etc. the choice of system is determined by the type of products for which parameter determination is required. It is also important when choosing a welding method; the hardness of the steel at the weld should remain fairly high.

Most of the listed parameters can be found in TU 14 3 1128 2000 for steel 09g2s, as well as for other grades. The technical specifications describe the requirements for the materials from which pipes are made for servicing gas fields and other areas of the industry.

The permissible stress for steel 09g2s is calculated depending on the following values:

• strength class and grade;
• temperatures at which it will be operated;
• thickness, sometimes configurations (circle, sheet, etc.).

Existing 09g2s analogues are foreign (European, Asian, others), most similar in mechanical and technical properties to the specified brand. However, the chemical composition can vary greatly. The Bulgarian version of this brand has the closest configuration.

What can be replaced?

Category C345 can be replaced by many alternative alloys, for example, 09G2S. Items from both brands have identical composition, but the latter has up to 0.08% (As) arsenic. This analogue is often used in industry for servicing metal structures operating under high pressure or at T = from -70 to +425 °C. The name contains the sign “G”, which means manganese, and the number 2 indicates its percentage (2%). Indicator 09 indicates total carbon (0.9%).

As for the hardness of 09G2S, its value can reach up to 490 Brinell pascals, which also increases the demand for this product. The materials are also capable of withstanding work in severe climatic conditions. The sheets themselves, the impact strength of which reaches 49KCU, can undergo hardening and heat treatment.

Also on the modern metallurgical market you can find German, Japanese, Bulgarian, Romanian versions of the C345, which will differ slightly in options and composition. However, objects can function freely with each other and under the same factors.

Advantages and disadvantages of 09G2S

The only drawback of 09G2S steel is its instability to rust. There are many more advantages:

1. strength;
2. duration of service life under normal conditions (more than 30 years);
3. heat resistance does not lose shape at temperatures from about -70 to 425C;
4. no temper fragility;
5. good weldability;
6. low cost;
7. high resistance to mechanical stress;
8. undemanding processing.

Susceptibility to rust limits the scope of use of products made from 09G2S steel, but its advantages over other alloys make it the most popular and widespread.

Categorization of rolled metal products of low-alloy steels GOST 19281-89

Price list – Rectangular low-alloy pipe st.09G2S

Price list – I-beam st.09G2S

Price list – Channel 09G2S

Price list – Low alloy sheet St 09G2S

Category of rolled low-alloy steels GOST 19281-89

When designating grades of low-alloy steels (GOST 19281-89), after the steel grade (with a dash), the category of rolled metal is written (example: 09G2S -12 , 09G2S -14 , 09G2S -15 , 10HSND -15 , 15HSND -15 ). The category indicates for which standardized characteristics the rolled metal was tested.

Grade 09g2s – structural steel, low-alloy, carbon. The amount of additives in it does not exceed 2.5%, and the numerical and alphabetic symbols in the name indicate their percentage in the metal. Decoding the marking according to GOST 5058-65 means that the carbon content in steel is 0.09%, the letter “G” in combination with the number “2” indicates the addition of 2% manganese, and “C” means a one-percent addition of silicon. Analogues of this steel - 09g2, 09g2dt, 09g2t, 10g2s, are also easily deciphered according to GOST. The main advantage of this brand is its good weldability, which is carried out both with heating and heat treatment, and without heating.

Main characteristics of steel 09g2s

Decoding of the 09G2S brand: The designation 09G2S means that 0.09% carbon is present in the steel, since 09 comes before the letters, followed by the letter “G” which means manganese, and the number 2 means a percentage of up to 2% manganese. Next comes the letter “C”, which means silicon, but since there is no number after C, this means the silicon content is less than 1%. Thus, the decoding 09G2S means that we have a steel with 0.09% carbon, up to 2% manganese, and less than 1% silicon, and since the total number of additives fluctuates around 2.5%, this is low-alloy steel. Sulfur and phosphorus, which negatively affect the toughness of steel, are used in the grade in small quantities.

• carbon – up to 1.2%;
• silicon – 0.5-0.8%;
• manganese – 1.3-1.7%;
• nickel – up to 0.3%;
• sulfur – up to 0.04%;
• phosphorus – 0.035%;
• chromium – up to 0.3%;
• nitrogen – up to 0.008%;
• copper – up to 0.3%;
• arsenic – 0.08%.
• iron – 96-97%.

Analogs and substitutes for steel 09G2S

The table shows the markings of alloys similar to 09G2S steel on foreign markets. Please note that not all analogues are accurate.

Foreign analogues of the material

Attention! Both exact and closest analogues are indicated.

Decoding steel

Steel grade C345 belongs to the group of high-strength steel for welded building metal structures. The chemical composition and strength characteristics are regulated by the state standard GOST 27772 of 1988. According to it, the “C345” marking is deciphered as follows:

• Carbon up to 0.15%. For steels, carbon is an integral component along with iron. Its main purpose is to strengthen the metal structure due to the formation of iron carbides. Hardness and strength are directly proportional to the quantitative carbon content in the composition. The other side of the coin of such alloying is a decrease in manufacturability: ductility and weldability.
• Silicon (up to 0.8%) is introduced for deoxidation. It increases the strength of steel while maintaining its toughness value. In addition, this element helps to increase C345’s resistance to scale formation and improves weldability. Alloying with silicon also has a beneficial effect on the elasticity of the alloy.
• Manganese (1.3 -1.7%), like the previous element, belongs to the group of deoxidizers. A small amount of manganese in the alloy has a positive effect on hardness and strength. It is worth noting that such an increase in mechanical characteristics does not in any way affect the ductility of the metal. In addition to all of the above, alloying with manganese gives the alloy greater resistance to impact loads.

These elements, along with iron, are basic for c345. But GOST 27772-88 also allows the inclusion of the following components:

• Nickel (up to 0.3%) increases the alloy’s resistance to corrosion, hardenability and heat resistance.
• Chromium (up to 0.3%) significantly increases the ability of steel to harden under the influence of temperature. Increases the corrosion resistance of metal due to the formation of dense chromium oxides on its surface. Makes steel more resistant to abrasive wear.
• Copper (up to 0.3%) prevents corrosion under the influence of an aggressive environment.

Comparison of 09G2S with brand 17G1S

Two popular grades of steel have a similar composition, but differ in a number of characteristics, especially in structure. The martensitic structure of 09G2S steel is optimal for load-bearing structures, therefore 09G2S steel is defined as structural and is widely used in construction. 17G1S is almost never used for the manufacture of load-bearing structures. The increased carbon content in this alloy ensures the formation of a ferritic structure, which, despite its strength, is more suitable and makes it possible to lay underground communications. Therefore, 17G1S steel is used to make pipes for heating networks and industrial engineering systems. It is also inferior in frost resistance, its lower temperature limit is -40C versus -70C for the 09G2S alloy, but is characterized by increased resistance to high temperatures up to +475C versus +425 degrees in the case of 09G2S.

Properties

The density of c345 is 7850 kgm3. The melting point is about 1550 ºC. A complete transition from solid to liquid is observed at 1620 ºC. Has good thermal conductivity. When the temperature increases by 20 ºC, it expands by 30-40 microns. Poorly conducts electric current. Magnetic

Brand C345 is not characterized by increased resistance to aggressive environmental influences. Reacts with oxygen under normal atmospheric conditions, forming rust. For this reason, it is used in construction after applying moisture-proof coatings to its surface. C345 dissolves in all types of acids and alkalis.

Steel has a low hardness of about 20.24 on the Rockwell scale. Temporary tensile strength - the load at which steel breaks - is 440-470 MPa. The metal begins to deform already at 345 MPa. Quite plastic. The relative elongation at break is 21%.

Steel C345 belongs to the first group of weldability. Welding does not require any preparatory operations: heating the surface, using fluxes, etc. The welds are dense and their strength under compressive load is not inferior to that of solid metal.

The steel is welded using manual arc welding. To prevent overheating, a low current of about 40 A is used. For better adhesion of the edges, the surface of the steel is pre-cleaned before welding.

Not hardened by heat treatment. The reason for this lies in the low carbon content and the lack of sufficient amounts of alloying elements such as chromium.

Features of welding steel 09G2S

Steel 09G2S is easy to weld; this property is ensured by the low carbon content in the alloy. There are no heating requirements; you can cook without preliminary heat treatment; this does not affect the strength of the seam. There are any welding methods and equipment; you can weld with a gas torch or an electric arc under a submerged arc. Steel products do not require hardening before or after welding and do not overheat during welding, so the grain size and ductility of the material do not change. Because 09G2S is a low-alloy low-carbon alloy; when welding it is necessary to use various electrodes for the appropriate purpose.

Application

The main and only purpose is the production of rolled profiles for the construction of metal structures. C345 is supplied to the rolled metal market in the form of:

• Hot and cold rolled sheets GOST 19903-90 and GOST 19904-90, respectively.
• Round bars GOST 2590-05.
• Hexagons GOST 2879-05.
• Equal and unequal angles GOTS 8509-09 - GOST 8510-09.
• Channels GOST 8240-09.
• I-beams GOST 8239-09.
• And other types of bent and rolled profiles.

The use of steel in construction is due to high technological properties on the one hand: ductility and weldability, and on the other hand, low cost relative to other steel alloys, which became possible due to the content of inexpensive components in its composition. Plus, C345 steel has sufficient strength for metal structures. All this makes c345 one of the most popular steels in construction.

Types and grades of steel

Steel. Types and grades of steel. Their application.

Steel is an alloy of iron and carbon with other elements, the carbon content in it is no more than 2.14%.

The most general characteristic is that steel is classified according to its chemical composition:

carbon steel (Fe – iron, C – carbon, Mn – manganese, Si – silicon, S – sulfur, P – phosphorus). Based on carbon content, it is divided into low-carbon, medium-carbon and high-carbon. Carbon steel is designed for statically loaded tools.

alloy steel - alloying elements are added: nitrogen, boron, aluminum, carbon, phosphorus, cobalt, silicon, vanadium, copper, molybdenum, manganese, titanium, zirconium, chromium, tungsten, nickel, niobium.

According to the production method and impurity content, steel differs:

ordinary quality steel (carbon less than 0.6%) - complies with GOST 14637, GOST 380-94. St0, St1, St2, St3, St4, St5, St6. The letters “St” indicate ordinary quality steel, the numbers indicate the marking number depending on the mechanical properties. It is the cheapest steel, but inferior in other qualities.

high-quality steel (carbon or alloy) - GOST 1577, carbon content is indicated in hundredths of % - 08, 10, 25, 40, the degree of deoxidation and the nature of solidification can additionally be indicated. High-quality carbon steel has high ductility and increased weldability.

Low-carbon high-quality structural steels are characterized by low strength and high ductility. Parts for cold stamping are made from sheet steel 08, 10, 08kp. Bolts, screws, nuts, axles, hooks, studs and other parts for non-essential purposes are made from steels 15 and 20.

Medium-carbon quality steels (st. 30, 35, 40, 45, 50, 55) are used after normalization and surface hardening for the manufacture of parts that have high strength and core toughness (axles, screws, bushings, etc.)

Steel 60 - steel 85 have high strength, wear resistance, and elastic properties. Crane wheels, rolling rolls, compressor valves, springs, leaf springs, etc. are made from them.

high quality - complex chemical composition with low phosphorus and sulfur content - according to GOST 19281.

Steel is also divided by application:

a) construction steel - carbon steel of ordinary quality. Has excellent weldability. The number indicates the conditional number of the steel composition according to GOST. The higher the reference number, the higher the carbon content, the higher the strength of the steel and the lower the ductility.

St0-3 - for secondary structural elements and non-critical parts (flooring, railings, lining, washers)

St3 is used for load-bearing and non-load-bearing elements of welded and non-welded structures and parts that operate at positive temperatures. GOST 380-88.

The quality standard provides for steel with an increased amount of manganese (St3Gsp/ps, St5Gsp/ps).

b) structural steel - GOST 1050

Carbon-based high-quality structural steels are used in mechanical engineering, for welded, bolted structures, for roofing work, for the manufacture of rails, railway wheels, shafts, gears and other parts of forklifts. The numbers in the marking indicate the carbon content in tenths of a percent.

St20 - lightly loaded parts, such as rollers, copiers, stops,

St35 - experiencing small stresses (axles, rods, levers, disks, traverses, shafts),

St45 (st40Х) - requiring increased strength (shafts, couplings, axles, racks)

Structural alloy steels are used for tractor tracks, the manufacture of springs, leaf springs, axles, shafts, automobile parts, turbine parts, etc.

c) tool steel - used for cutting tools, high-speed steel for cold and hot deformation of materials, for measuring instruments, for the production of hammers, chisels, chisels, cutters, drills, files, razors, rasps.

U7, U8A (the figure is tenths of a percent in terms of carbon content). Carbon steels are produced in high quality and high quality. The letter "A" stands for high quality carbon tool steel.

d) alloy steel - universal steel containing a special impurity. Silicon content more than 0.5%, manganese more than 1%. GOST 19281-89. If the content of the alloying element exceeds 1 - 1.5%, then it is indicated by a number after the corresponding letter.

low-alloy steel - where alloying elements are up to 2.5% (09G2S, 10HSND, 18KhGT). Low-alloy steel can be used in conditions of the far north, from -70 degrees C. Low-alloy steel is distinguished by greater strength due to a higher yield strength, which is important for critical structures.

medium alloyed (2.5 -10%),

highly alloyed (from 10 to 50%)

Steel 09G2S is used for steam boilers, apparatus and containers operating under pressure and temperatures from minus 70 to plus 450 degrees; it is used for critical sheet welded structures in chemical and petroleum engineering, and shipbuilding.

What is the difference between galvanized, stainless and black steel

Speaking about corrosion resistance indicators, stainless steel is preferable to galvanized and black steel; these are different categories of protection. Galvanized steel is protected from corrosion by a thin or thick layer of zinc, and stainless steel is protected by the content of alloying additives in the alloy structure. This is a big difference, because... It is easy to damage the zinc layer, revealing unprotected steel behind it. Stainless steel does not need a protective film; it is protected from the inside by its own chemical properties until the end of its service life; the absence of a coating does not affect it in any way.

Black steel has no protection at all, so it is the most susceptible to corrosion. To increase its service life, it is recommended to coat it with powder paint and process it in a polymerization oven.

By service life

The service life of working parts for each of the steels differs by a factor of two: 50 years for the first versus 25 years for the second and 10 years for the third. And these are average figures, because... Due to damage to the zinc layer, the product will most likely fail earlier. Black steel is the least wear-resistant.

Environmentally friendly

When heated or exposed to acids, zinc releases harmful compounds zinc oxide and phosphides. Poisoning can be of varying strength, including death if the damage is extensive. Stainless steel is completely safe in any product and has proven itself in the production of cookware. Ferrous metal is also not toxic, but due to its susceptibility to corrosion, it is almost always isolated from humans by a protective layer of paint.

By cost

The lower limit of the cost of 1 ton of ordinary stainless steel sheet is 113 thousand rubles. A galvanized hot-rolled sheet of the same weight can be purchased at a price of 67 thousand rubles. The price of the same sheet of black steel starts from 45 thousand rubles. The cost is also influenced by the quality characteristics of the steel and the choice of manufacturers. Read more about this in the materials on our website.

Chemical composition

The chemical composition of steel C345 according to heat analysis of a ladle sample must comply with the standards given in table. 1 (Table 1-2 GOST 27772-88).

Chemical composition of steel according to heat analysis of ladle sample

Note: When smelting steel from Kerch ores, the mass fraction of arsenic is no more than 0.15%, phosphorus is no more than 0.030%.

The addition of aluminum and titanium is allowed based on obtaining a mass fraction of titanium in rolled products of 0.01-0.03% (clause 2.8 of GOST 27772-88).

At the consumer's request, the mass fraction of phosphorus should be 0.030%, sulfur - no more than 0.035% (clause 2.9 of GOST 27772-88).

It is allowed to treat steel with synthetic slags, vacuum degassing, blowing with argon, modifying steel with calcium and rare earth elements based on the introduction of no more than 0.02% calcium and 0.05% rare earth elements into the metal (clause 2.10 of GOST 27772-88).

It is permissible for the manufacturer not to conduct a chemical analysis of steel for chromium, nickel, copper, and arsenic content. The required chemical composition is guaranteed by the manufacturer. In steel smelted from Kerch ores, the determination of arsenic is mandatory (clause 2.13.1 of GOST 27772-88).

The weldability of steel is guaranteed by the manufacturer (clause 2.18 of GOST 27772-88).

Metal constructions

Message from eilukha : Thank you! The meaning of the table is unclear. 5, what do the pros and cons mean?

If it is “+”, then the normalized characteristic from the first column of the table is checked, if “-”, then it is not checked.

See also SP 16.13330.2011 “Updated edition of SNiP II-23-81*” Appendix B, Table B.1.

Message from Dart Sith : look in the joint venture in the appendices there is a sign about groups of steels, the whole meaning is revealed there

What European marking corresponds to steel C345 of the 1st category in terms of impact strength? S355J2 or S355K4?

Message from *KSV* : S355J2 - “we” don’t have one like that, similar steel - 17G1S; S355K4 - I don’t know this one

Please re-read the question

Message from user277418 : Which European marking corresponds to C345 steel of the 1st category in terms of impact strength? S355J2 or S355K4?

You take it and compare, damn it. Soon there will be questions: “Which channel corresponds to the 20B1 I-beam in terms of the moment of resistance”

Message from Jabberwocky : You take it and compare, damn it. Soon there will be questions: “Which channel corresponds to the 20B1 I-beam in terms of the moment of resistance”

Thanks for the answer, but the benefit in it tends to zero.

According to Table 5. GOST 27772-88 for steel C345 of the 1st category, impact strength is normalized at a temperature of -40C, and in Table. B3 SP 16.13330 - at a temperature of -20 Based on the above, European steel should be standardized for what temperature?

I rephrased the question a bit.

Message from user277418 : Thanks for the answer, but the benefit in it tends to zero.

Message from user277418 : Which European marking corresponds to C345 steel of the 1st category in terms of impact strength? S355J2 or S355K4?

Posted by user277418 : Based on the above, should European steel have the same toughness?

The answer is already in the question itself, no?

I think that in order to “respond”, European steel must have a toughness no lower than ours, taking into account the availability (take test standards and compare methods for obtaining impact strength figures - they may differ). Or you test bourgeois steel using our methods (if you have a laboratory and it’s the most cunning steel)

Message from Jabberwocky : what question?

The answer is already in the question itself, no?

I think that in order to “respond”, European steel must have a toughness no lower than ours, taking into account the availability (take test standards and compare methods for obtaining impact strength figures - they may differ). Or you test bourgeois steel using our methods (if you have a laboratory and it’s the most cunning steel)

Message from user277418 : According to Tab 5. GOST 27772-88 for steel C345 of the 1st category, impact strength is normalized at a temperature of -40C https://c2n.me/iFG4A9, and in Tab. B3 SP 16.13330 - at a temperature of -20 https://c2n.me/iFG7iT Based on the above, European steel should be standardized for what temperature?

Added pictures for clarity

Message from Jabberwocky : According to GOST. The only thing is, I don’t remember exactly 27772-88 (and the Internet was castrated for us).. Is there a table for rental or sheet given?

Mechanical properties

The mechanical properties of shapes and sheets made of steel C345 in tension, impact strength, as well as bending test conditions must meet the requirements of Table 2 (Table 3-4, clause 2.7 of GOST 27772-88).

Mechanical properties of rolled steel C345

Impact strength standards are given for rolled products with a thickness of 5 mm or more (clause 2.22 of GOST 27772-88).

It is allowed to reduce the impact strength value on one sample by 30%. In this case, the average value of the test results must not be lower than the standards in Table. 2 (clause 2.23 GOST 27772-88).

Rolled steel C345 is produced in categories 1, 2, 3 and 4 depending on the requirements for impact bending tests. Standardized impact strength indicators for rolled products of various categories specified in the order are given in Table 3 (Table 5, clause 2.24 of GOST 27772-88).

The calculated resistances in tension, compression and bending of sheet, wide-band universal and shaped rolled products made of steel grade C345 in accordance with GOST 27772–88 for steel structures of buildings and structures should be taken according to table. 4 (Table 51 Appendix 1 SNiP II -23-81)

Calculated resistance of rolled steel C345

1. The thickness of the shaped steel should be taken as the thickness of the flange (its minimum thickness is 4 mm).
2. The values ​​of the calculated resistances were obtained by dividing the standard resistances (yield strength and tensile strength according to GOST 27772–88) by the reliability factor for the material γm = 1.025 (clause 3.2 of SNiP II -23-81), rounded to 5 MPa (50 kgf/cm²) .

Analogs of steel grade C345

Carbon steel C345 according to GOST 27772-88 corresponds to low-alloy carbon steels of increased strength of the following grades:

• 09G2S according to GOST 19281 (Appendix 1 GOST 27772-88, Appendix 3 GOST 19281-89 and Appendix 4 GOST 19281-89)
• 12G2S according to GOST 19281 (Appendix 1 GOST 27772-88)
• 10G2S1 , 10KHNDP , 15HSND and 15GF according to GOST 19281 (Appendix 3 GOST 19281-89 and Appendix 4 GOST 19281-89)
• 17GS , 17G1S and 14HGS according to GOST 19281 (add. 4 GOST 19281-89)
• 14G2 and 15HSND according to GOST 19282-73 (Table 51b appendix 1 SNiP II -23-81)
• 12G2S-1 according to TU 14-1-4323–88 (Table 51b appendix 1 SNiP II -23-81)
• 09G2-2 , 09G2S-1 and 14G2-1 according to TU 14-1-3023–80 (Table 51b appendix 1 SNiP II -23-81)
• 390 according to TU 15-15-146-85 (Table 51b appendix 1 SNiP II -23-81)
• VStTPs according to GOST 14637–79 (Table 51b, Appendix 1, SNiP II -23-81)

We manufacture the following standard metal products:

Flight stairs, platforms, stepladders and their guards according to series 1.450.3-7.94.2:

Flight stairs, landings, stepladders and their railings according to series 1.450.3-3.2:

Steel stepladders for wells according to:

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