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 structures made from 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.
Description of steel 09G2S: Most often, rolled products from this steel grade are used for a variety of building structures due to 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 we produce high-quality pipeline fittings. 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 (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.
Description of steel 09G2S: Most often, rolled products from this steel grade are used for a variety of building structures due to their 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 the production of complex structures from sheet metal of this grade for the 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 weld in the welded product increases and tension zones are eliminated.
Properties of steel 09G2S: steel 09G2 after processing 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 total (δtotal) and uniform (δр) elongation, DFMS have greater strength and a lower ratio σ0.2/σв (0.4–0.6) than conventional low-alloy steels. At the same time, the resistance to small plastic deformations (σ0.2) of DFMS is lower than that of steels with a ferrite-pearlite structure.
At all levels of strength, all indicators of technological plasticity of DFMS (σ0.2/σв, δр, δtotal, Erichsen stretch, deflection, cup height, etc.), except for hole expansion, 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 317 and 350 MPa for the weld and base metal (σв = 550 MPa), respectively, i.e. 50 and 60% of 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 (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.
