Description of steel 09G2S: Most often, rolled steel from this grade of steel is used for a variety of building structures due to its high mechanical strength, which allows the use of thinner elements than when using other steels. The stability of properties over a wide temperature range allows the use of parts from this grade in the temperature range from -70 to +450 C. Also, easy weldability allows them to be manufactured from rolled sheets of this grade complex designs for chemical, oil, construction, shipbuilding and other industries. Using hardening and tempering, high-quality pipeline fittings are produced. High mechanical resistance to low temperatures also makes it possible to successfully use pipes from 09G2S in the north of the country.
The brand is also widely used for welded structures. Welding can be carried out both without heating and with preheating to 100-120 C. Since there is little carbon in steel, its welding is quite simple, and the steel is not hardened or overheated during the welding process, due to which there is no decrease in plastic properties or increasing its granularity. The advantages of using this steel also include the fact that it is not prone to temper brittleness and its toughness does not decrease after tempering. The above properties explain the ease of using 09G2S over other steels with a high carbon content or additives that cook less well and change properties after heat treatment. For welding 09G2S, you can use any electrodes designed for low-alloy and low-carbon steels, for example E42A and E50A. If sheets up to 40 mm thick are welded, then welding is carried out without cutting the edges. When using multilayer welding, cascade welding is used with a current of 40-50 Amps per 1 mm of electrode to prevent overheating of the welding site. After welding, it is recommended to heat the product to 650 C, then hold it at the same temperature for 1 hour for every 25 mm of rolled product thickness, after which the product is cooled in air or in hot water- due to this, the hardness of the seam in the welded product increases and tension zones are eliminated.
Properties of steel 09G2S: s Tal 09G2 after treatment for a two-phase structure has an increased endurance limit; at the same time, the number of cycles to failure in the low-cycle fatigue region increases approximately 3–3.5 times.
Hardening of DFMS (double-phase ferritic-martensitic steels) creates areas of martensite: every 1% of the martensitic component in the structure increases the tensile strength by approximately 10 MPa, regardless of the strength and geometry of the martensite phase. The isolation of small areas of martensite and the high plasticity of ferrite significantly facilitate the initial plastic deformation. A characteristic feature of ferritic-martensitic steels is the absence of a yield area on the tensile diagram. With the same value of the total ( δ total) and uniform ( δ p) DFMS extensions have greater strength and more low attitude σ 0,2 /σ in (0.4-0.6) than conventional low-alloy steels. At the same time, resistance to small plastic deformations ( σ 0.2) for DFMS is lower than for steels with a ferrite-pearlite structure.
At all strength levels, all indicators of technological plasticity of DFMS ( σ 0,2 /σ V, δ R, δ generally, Erichsen hood, deflection, cup height, etc.), in addition to the hole distribution, exceed similar indicators of conventional steels.
The increased technological ductility of DFMS allows them to be used for sheet stamping of parts of fairly complex configurations, which is an advantage of these steels over other high-strength steels.
The corrosion resistance of DFMS is at the level of corrosion resistance of deep drawing steels.
DFMS are welded satisfactorily by spot welding. The endurance limit for alternating bending is for the weld and base metal ( σ в = 550 MPa) respectively 317 and 350 MPa, i.e. 50 and 60% о in the base metal.
In the case of using DFMS for parts with massive sections, when it is necessary to ensure sufficient hardenability, it is advisable to use compositions with a high content of manganese or with the addition of chromium, boron, etc.
The economic efficiency of using DFMS, which is more expensive than low-carbon steels, is determined by the savings in the mass of parts (by 20-25%). The use of DFMS in some cases makes it possible to eliminate the strengthening heat treatment of parts, for example, high-strength fasteners produced by cold heading.
Physico-chemical properties of steel 09G2S
Steel grade 09G2S is widely used due to its high physical, chemical and mechanical properties. The physical properties of steel provide them with sufficient strength. The alloy does not undergo any additional processing. The weldability of this material is not limited. Let us give the values of some physical properties of this steel at a temperature of 100 o C:
- density - 7832 kg/m3;
- modulus of elasticity - 2.03x10 5 MPa;
- specific heat capacity - 494 J/(kg deg);
- resistivity - 1.9x10 -7 Ohm m.
Decoding 09G2S
It is a structural low-alloy alloy. The alloying additives included in its composition are designated by letters: manganese - “G”; silicon - “C”. The carbon content in steel is 0.09%. This is evidenced by the double-digit figure ahead. The number 2 corresponds to the percentage of manganese. The absence of a number after the letter C in the marking means that the proportion of silicon in the alloy is less than 1%.
To the useful characteristics of this brand it is also necessary to add following features: the welding process does not lead to overheating and hardening of the steel; retention of plastic properties is observed high level; At the same time, the grain size of the material does not increase. The presence of such technological properties allows it to be used for the manufacture of reliable welded structures.
Areas of application of steel 09G2S
09G2S steel is used to produce shaped, sectional, and strip metal products, the thickness of which is in the range of 10-100 mm. Building construction made of this material are lighter and their production is more economical. Welded metal structures made from elements and parts made from this steel can be used in a wide temperature range: from -70°C to +450°C.
In addition, steel of this grade can be used to create the thinnest possible elements. At the same time, they have high strength and durability (service life of at least 30 years), ensuring the safety of the structure. This quality allows it to be used in the construction industry and shipbuilding. Welding work can be carried out both with preheating (100-120 o C) and without it.
Peculiarities
Made from this steel, it is highly flexible. Due to this, it is used to create structures of complex shapes. Consumers of steel products, in particular pipes and pipeline fittings, are the oil, gas and chemical industries. It is also used to make steam boilers, apparatus and containers designed to operate in conditions high pressure and temperature.
Characteristics of high strength steel
High strength steel grades
Steel is one of the most important materials that is used in almost all industries. Depending on the application, high-strength steel has different requirements. Steel grades differ in structure, chemical composition and by its properties (physical and mechanical).
Steel is a deformable alloy of iron with carbohydrate (no more than 2 percent) and admixtures of other elements: manganese, silicon, phosphorus. Special requirements are placed on high-strength fasteners. Therefore, to obtain steel that will ideally meet all characteristics, special impurities are added - alloying elements. These are chromium, tungsten, vanadium, titanium, manganese or silicon.
Steel 20
Quality carbon structural steel
pipes for superheaters, manifolds and pipelines of high-pressure boilers, sheets for stamped parts, cemented parts for long and very long service at temperatures from -40 to 350 degrees.
STEEL GRADE 3
Regular quality carbon steel.
This type of steel is in greatest demand in construction. The reason for such popularity is manufacturability, durability and attractive price. Another advantage of this alloy is the ability to make products from it that can withstand heavy loads and have good impact resistance.
Steel 3 is produced according to GOST 380-94, according to which steel is marked with the letters “St” with a serial number from 0 to 6. The higher this number, the greater the amount of carbon contained in the steel. Which means better strength, but at the same time worse plastic characteristics. Steel 3 welds well, is non-flocene sensitive, and is not prone to temper brittleness. Steel 3 contains: carbon - 0.14-0.22%, silicon - 0.05-0.17%, manganese - 0.4-0.65%, nickel, copper, chromium - no more than 0.3%, arsenic no more than 0.08%, sulfur and phosphorus - up to 0.05 and 0.04%. The amount of these components in the St3 alloy is not allowed above the specified values.
The basis of steel is ferrite. Its characteristics do not allow it to be used in its pure form. To improve the strength of ferrite, steel is saturated with carbon, chromium, nickel, silicon, manganese are added (alloyed) and additional thermal hardening is carried out.
Steel 3 withstands a wide temperature range under variable loads. It welds well, is stamped in cold and hot conditions, and is drawn. Can be used without heat treatment.
Weldability of steel
Without restrictions - welding is performed without heating and without subsequent heat treatment. In steel classified as good, the carbon content is less than 0.25%. They are welded without the formation of hardening structures and cracks in a wide range of welding conditions.
Application temperature
The minimum application temperature (the temperature of the coldest five-day period in the region) is minus 30.
The maximum temperature of use is plus 300.
STEEL GRADE 35
High quality medium carbon steel.
This type of steel is used for parts that require high ductility and impact resistance. High-quality carbon steels of type 35 are manufactured according to GOST 1050-88 and are marked with two-digit numbers that indicate the average carbon content in hundredths of a percent. For example, steel 35 (0.35%). It has high strength (σв = 640...730 MPa, σ0.2 = 380...430 MPa) and relatively low ductility (δ = 9...14%, ψ = 40...50%). In addition, this type of steel is not susceptible to medium stress, is resistant to deformation and wear, and is not subject to cracking and corrosion. Therefore, steel 35 is used in the production of high-strength fasteners and flange connections. Temperature range: -40 to +450 degrees Celsius
35 steel has limited weldability. Methods of welding RDS, ADS submerged arc and gas shield, ESW. We recommend heating and subsequent heat treatment. CTS without restrictions.
Weldability of steel
Structural grade steel 35
limited welding. With an increase in carbon in the steel, the heat-affected zone and the weld are hardened, hardness increases, and welded joints become more brittle and prone to cracking.
Satisfactory steels have a carbon content of 0.25 to 0.35%. They are less prone to cracking and correct modes welding produces a high-quality seam. To improve the quality of welding, heating is often used.
Application temperature
STEEL GRADE 35X
Alloy steel, chromium
Steel Fasteners 35X have high structural strength, guaranteeing reliability of the structure. In addition, steel 35X It resists shock loads well, has a large reserve of viscosity and high fatigue resistance. Also, steel 35X has high resistance to wear, corrosion, cracks and other defects.
The main advantage of fasteners made from 35X alloy structural steel over carbon ones is higher strength due to ferrite hardening and greater hardenability, less growth of austenite grains when heated, and increased impact strength. And the level of mechanical properties is increased due to heat treatment.
Weldability of steel
Limited weldability.
Application temperature
The minimum temperature of use (the temperature of the coldest five-day period in the region) is minus 40.
The maximum temperature of use is plus 425.
STEEL GRADE 40X
Structural alloy steel.
Steel grade 40X contains 0.40% carbon and less than 1.5% chromium. This steel is quite difficult to weld. Therefore, in order to obtain a high-quality welded joint, additional operations are necessary. When welding, heating to 200-300 degrees will be required, and then heat treatment by annealing.
Thanks to the addition of chromium, steel 40X fasteners have hardness, strength, heat resistance and corrosion resistance. Steel 40X designed for significant loads. Mechanical properties of steel 40x: short-term strength - 570 - 940 MPa, proportionality limit - 320 - 800 MPa, relative elongation - 13 - 17%, relative contraction - 35 - 55%, impact strength - 400 - 850 kJ / sq.m.
The advantages of this steel grade: resistance to high and low temperatures and their sudden changes, can be used outdoors and even in aggressive, humid environments. Another undeniable advantage of fasteners made from this particular grade of steel is the absence of the need to process and clean the surface.
Weldability of steel
Limited weldability. Preheating and subsequent heat treatment are recommended.
Application temperature
The minimum temperature of use (the temperature of the coldest five-day period in the region) is minus 40.
The maximum temperature of use is plus 425.
STEEL GRADE 45
Steel grade 45
has high durability and strength. Steel 45
used in the manufacture of mechanical parts used under increased loads and requiring resistance (impact, friction). The mechanical properties of this steel allow it to withstand significant temperature changes and other adverse climatic influences. This steel can withstand temperature tests from 200 to 600 degrees Celsius.
When using Art. 45 it should be remembered that:
. strength decreases when heated to 200 0C;
. steel is difficult to weld and is characterized by low flone sensitivity.
Steel grade 45
- medium carbon; ideal for the manufacture of parts that require high strength or high surface hardness, as well as parts that are moderately loaded and not subject to abrasion during operation.
Weldability of steel
High carbon steel grade 45
It is recommended to connect by contact welding. Limited weldability steels have a carbon content of 0.36 to 0.45% and are prone to cracking. Welding requires mandatory heating. When welding them, special technological processes are required.
Application temperature
The minimum temperature of use (the temperature of the coldest five-day period in the region) is minus 40.
The maximum temperature of use is plus 425.
Steel grade 09G2S
Low alloy structural steel.
Designation 09G2S indicates that the steel contains 0.09% carbon, the letter “G” means manganese, and the number 2 indicates a percentage of up to 2% manganese. The letter "C" stands for silicon, silicon content less than 1%.
The main advantage of this steel is its high mechanical strength, which allows the use of thinner parts compared to parts made from other steels. Which means the parts are made of steel 09G2S have less weight, which is more economically profitable. In addition, another advantage of this steel is its low tendency to temper brittleness.
Weldability of steel
steel grade 09G2S widely used for welded structures. Welding can be done either without heating or with preheating up to 100-120 degrees Celsius. Welding is quite simple, and the steel is not hardened or overheated during the welding process, so there is no decrease in plastic properties or an increase in its grain size. At air temperatures of minus 15 °C and below, local preliminary heating is used, regardless of the thickness of the steel.
Application temperature
The minimum temperature of use (the temperature of the coldest five-day period in the region) is minus 70.
The maximum temperature of use is plus 450.
