Steel for building structures C255. Steel C255 construction carbon Types of processing and application

Steel grade C225 is used for the manufacture of sheet and profile metal products intended for the installation and assembly of critical metal structures with bolted, riveted, welded and seam joints. The brand is the most popular and in demand in the construction industry, having no restrictions when performing welding work.

Deciphering steel C255

Marking C means that this steel is intended for use in construction, and the number 255 determines the yield strength of finished rolled products in N / mm 2. It is applied to the metal surface with yellow insoluble paint.

GOST

Requirements for metal must comply with GOST 27772-88, which defines specifications for the manufacture of rolled products for metal structures in construction. In accordance with the state standard, C255 steel is used to produce: angle, I-beam, channel, bent profiles of various configurations, as well as smooth and corrugated metal sheets. The section thickness of rolled elements cannot be more than 30 mm and less than 4 mm.

Compound

The mass fraction of the elements that make up this steel is given in the table of the state standard:

• about 97% iron (Fe);
• 0.22% carbon (C);
• 0.65% manganese (Mn);
• 0.15-0.3% silicon (Si);
• 0.3% chromium (Cr), nickel (Ni) and copper (Cu);
• 0.2% aluminum (Al);
• 0.05% sulfur (S);
• 0.04% phosphorus (P).

When using ores from individual deposits, an increased content of manganese by 0.2% and the presence of arsenic are allowed, but not more than 0.12%.

Analogues of steel С255

By chemical composition and mechanical properties state standard defines the following as analogues of C255 domestic brands:

• VSt3sp5, VSt3ps5 and VSt3ps6;
• St3Gps and St3Gsp;
• 18sp, 18Gps and 18Gsp.

From foreign analogues according to ISO 630 standardization should be called:

• Fe 360-B (E 235-B)
• Fe 360-C (E 235-C)
• Fe 360-D (E 235-D).

Types of processing and application

The amount of carbon and alloying additives in the chemical composition of C255 steel makes it possible to use any type of welding to connect parts and structural elements. Thermal, laser, hydraulic and mechanical processing technologies can be used for cutting rolled products and cutting sheets. Quite simple drilling, milling and the possibility of threading are noted.

In construction, rolled steel from C255 is used for the installation of metal structures of group 1, which includes welded elements designed to work in especially difficult conditions. Including vibration, dynamic and moving loads. The first group includes structural elements of bridge spans, supports for power lines, crane beams, load-bearing trusses, overpasses, stairs and others.

It is allowed to use rolled steel grades in other types industrial production except for construction. For example, for the manufacture of housings and load-bearing elements in mechanical engineering.

Brand: S255
Grade: Steel for building structures
Use in industry: production of rolled products intended for building steel structures with welded and other joints
Weldability of material: no restrictions.

Steel grade C255 is one of the most popular and in demand in the construction industry, as it is endowed with excellent strength characteristics and has no restrictions on weldability. It is delivered to facilities in the form of rolled metal (including shaped) for subsequent use as part of various metal structures (connection - welding or any other).

Steel S255: chemical composition and GOSTs for hire

Carbon steel C255 (the proportion of carbon is about 0.2%) is produced in accordance with GOST 27772-88, which determines the following composition of the chemical elements of the steel alloy:

• Fe - about 97%
• C - up to 0.22%
• Mn - up to 0.65%
• Si - 0.15-0.3%
• Ni - up to 0.3%
• Cr - up to 0.3%
• Cu - up to 0.3%
• S - up to 0.05%
• P - up to 0.04%
• N - up to 0.012%

Hot-rolled shaped steel from C255 steel:

• GOST 8509 - equal-shelf corner
• GOST 8510 - unequal corner
• GOST 8239, 26020 - I-beam
• GOST 8240 - channel
• GOST 19425 - I-beam and special channel

In addition, carbon steel 255 is used for the production of rolled products:

• GOST 19903 - sheet
• GOST 82 - universal broadband
• GOST 8568 - sheet with lentil and rhombic corrugation

Bent profiles are also made from steel of this grade: according to GOST 7511, 8278, 8281, 8282, 8283, 9234, etc.

Analogues

analogues carbon steel C255 can perform:

• St3Gps
• St3Gsp
• VSt3sp5
• VSt3Gps5
• Vst3ps6
• VSt3sp5-1
• VSt3Gps5-1
• 18Gps
• 18Gsp
• E 235-B (Fe 360-B)
• E 235-C (Fe 360-C)
• E 235-D (Fe 360-D)

Steel s255: properties and characteristics

The main mechanical properties of C255 rolled products can be found here:

The use of steel grade C255

Builders distinguish 4 groups of building metal structures, classified according to the degree of their responsibility and the conditions of their operation. The most demanding is the first group, which includes welded structures that are forced to work in particularly difficult conditions, including those exposed to sufficiently large vibration, dynamic and moving loads. In this case, it is allowed to use only the C255 steel we are considering, as well as C285, C345 or C375.


The first group includes such structures as elements of bridge spans, power transmission line supports, crane beams, unloading and bunker racks, transport galleries, trusses, etc.

steel sheet prices

In APEX metal you can buy sheet st 3 in sheets and rolls at a low price:

• for use in construction
• manufacture of products general purpose, pipes, bent profiles

Depending on the purpose, a sheet of steel 3 is produced from grades with different chemical composition and properties in accordance with GOST 380, GOST 19281, GOST 27772, TU.

• Hot-rolled thin and thick plates are made of steel Z of ordinary quality with a chemical composition that must comply with the requirements of GOST 380:

• Thick hot-rolled sheet of high-strength steel with a basic chemical composition in accordance with GOST 19281 is produced with regulated or controlled rolling with accelerated cooling to ensure the following strength classes:

• Hot-rolled sheet metal GOST 27772, intended for the manufacture of welded and other building structures:

Construction steel grades - analogues and replacement

One of the important characteristics of building rolled steel 3 is the resistance to brittle fracture. To confirm these properties, samples of steel sheets are tested for impact bending at lower temperatures.

The level of resistance to brittle fracture of sheet metal according to GOST 27772 is guaranteed by the required value of impact strength (KCU - when tested for impact bending with a concentrator U). For steels smelted according to EN standards, this value is the fracture work factor (KV).

Sheet and profile metal rolling is used in various industries, it is intended for the assembly of metal structures with riveted, bolted and welded joints. Steel C255 is most in demand in the construction industry, it has no restrictions on welding. The description of the alloy determines its applicability in the creation of critical structures that can be exposed to atmospheric and other influences.

Chemical composition

All alloys are characterized by their specific chemical composition. Established norms determine the concentration of all elements in a certain range. Among the features of the chemical composition of C 255, we note the following points:

1. Most of the composition is iron, about 97%. This element is part of almost all alloys.
2. Carbon determines the hardness and strength of the metal, as well as its brittleness and degree of weldability. The C255 steel in question contains about 0.22% carbon. Too high a concentration of carbon leads to structural brittleness and weldability problems. However, a decrease in the amount of this chemical in the composition causes a decrease in the hardness and strength of the structure. It is important not only how much carbon is in the composition, but how evenly it is distributed throughout the structure. The uneven arrangement of carbon leads to a decrease in performance.
3. Manganese is included in the composition of many metals, in this case it is about 0.65%.
4. Silicon largely determines the main operational properties, its concentration is from 0.15 to 0.3%. Silicon also affects strength and weldability, hardness and other important characteristics.
5. Copper, nickel and chromium account for 0.3% each. The low concentration of chromium determines that the surface can become corroded. Prolonged exposure to precipitation and some chemical substances leads to corrosion. Too long operation with such damage to the metal leads to a decrease in the strength of the supporting structures and a deterioration in decorative qualities.

Sulfur and phosphorus are also included in the composition in a small amount. These substances degrade the performance of C255 steel, for example, strength.

Mechanical properties

The main characteristics of steel C255 can be found in the special literature. Some qualities depend on temperature environment and some other factors. The mechanical properties of the alloy are as follows:

1. The yield strength of steel C255 is 255 MPa.
2. Temporary resistance 360 ​​MPa.
3. The relative elongation of the workpiece is 25%.

If necessary, the performance of C255 steel can be improved by heat and other types of treatment. Most often, surface hardening and tempering is carried out:

1. In the first case, the surface hardness is increased. Exposure to high temperature leads to the fact that the structure of the metal is rebuilt and compacted. For hardening, special equipment is used that heats the workpiece to the required temperature. Cooling involves the use of a water or oil bath. In order to reduce the likelihood of scale and other defects, oil is used to cool the workpiece, as it provides a uniform temperature decrease.
2. Tempering provides for the reduction of internal stresses, which can cause surface or internal defects. A similar heat treatment method involves heating to a lower temperature, but the increase and decrease in temperature is carried out gradually. Due to this, the main operational characteristics of steel C255 are increased.

Quenching and tempering in most cases are carried out when the workpiece is small. Massive products are difficult to process, as their heating requires large-sized specialized equipment.

The considered alloy is characterized by excellent mechanical properties, but at the same time it is not resistant to corrosion. That is why the structures being created require protection from moisture and some other chemicals. In most cases, double painting of the surface with waterproof paint is carried out with preliminary priming of the base. To significantly increase the protection of the structure, hot-dip galvanizing is carried out, since zinc withstands moisture and chemicals.

Application area

The considered steel grade C255 is used to create metal structures that belong to the first group.

This group is characterized by welded elements used in particularly difficult operating conditions.

The following loads can be applied to the created structures:

1. Dynamic - gradual increase and decrease in pressure. To withstand the dynamic load, the metal must have ductility.
2. Movable - change in the point of pressure concentration. Such an impact can lead to the destruction of load-bearing elements.
3. Vibration - a similar effect is inherent in bridges and other supporting structures. Vibration can lead to deformation of the weld and fasteners.

Steel 255 is found in the structures of bridges, overpasses, stairs and other load-bearing structures, which are subjected to a high load. In some cases, it is allowed to use metal in the manufacture of critical mechanisms in the engineering industry.

Alloy analogues

According to the chemical composition and mechanical properties, several similar alloys are distinguished. An analogue of steel C255 can be of domestic and foreign origin. Similar domestic brands are as follows:

1. 18sp, 18Gsp and 18Gps.
2. VSt3sp5 and VSt3ps6.
3. St3Gps and St3Gsp.

Foreign analogues are manufactured taking into account the ISO 630 standard. This group includes the following glories:

1. Fe 360-C (E 235-C).
2. Fe 360-B (E 235-B).
3. Fe 360-D (E 235-D).

Some analogs can be improved by thermal and chemical processing. All alloys are characterized by high weldability and machinability.

Steel marking 255

When marking steel C255, certain standards are applied that allow you to quickly determine the main properties of the metal. Decryption is carried out as follows:

1. The first letter C indicates that the metal is applicable in construction.
2. The numbers used for marking indicate the fluidity of the finished product, which is measured in N / mm 2.
3. Often the marking is applied to the surface of the workpieces with yellow insoluble paint.

Download GOST 27772-88

For this brand, the requirements of GOST 27772-88 apply. They determine the possibility of using the material in the manufacture of corners, bent profile and channel, I-beam. The sectional thickness of the manufactured elements must be at least 4 mm and not more than 30 mm.

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