Steel grade 255 decoding. S255 construction carbon steel. Application of steel grade C255

Brand: C255
Class: Steel for building structures
Use in industry: production of rolled products intended for construction steel structures with welded and other connections
Weldability of the material: without restrictions.

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

Steel S255: chemical composition and GOST standards for rental

Carbon steel C255 (carbon share is about 0.2%) is produced according to GOST 27772-88, which defines the following composition chemical elements 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 C255:

• GOST 8509 – equal angle angle
• 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 metal 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

Analogs 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 basic mechanical properties of rolled C255 can be found here:

Application 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 forced to work in particularly difficult conditions, including those exposed to fairly large vibration, dynamic and moving loads. In this case, it is allowed to use only the steel grade C255 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 overpasses, transport galleries, trusses, etc.

Prices for steel sheets

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

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

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

• Thin-sheet and thick-sheet hot-rolled products are made from steel Z of ordinary quality with a chemical composition that must meet the requirements of GOST 380:

• Thick-sheet hot-rolled sheets of high strength steel 3 with a basic chemical composition in accordance with GOST 19281 are produced with regulated or controlled rolling with accelerated cooling to ensure the following strength classes:

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

Construction steel grades - analogues and replacement

One of important characteristics Construction rolled steel 3 is resistant to brittle fracture. To confirm these properties, samples of steel sheets undergo impact bending tests at decreasing temperatures.

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

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

Decoding steel C255

Marking C means that this steel is intended for use in construction, and the number 255 determines the yield strength of the finished steel 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 technical specifications for the production of rolled products for metal structures in construction. In accordance with the state standard, the following are made from steel C255: angles, I-beams, channels, bent profiles of various configurations, as well as smooth and corrugated metal sheets. The cross-sectional 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 manganese content of 0.2% and the presence of arsenic are allowed, but not more than 0.12%.

Analogues of steel C255

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

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

Among the foreign analogues for ISO 630 standardization, the following should be mentioned:

• 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 allows the use of any types 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. It is noted that drilling, milling and threading are quite simple.

In construction, rolled steel C255 is used for the installation of metal structures of group 1, which includes welded elements designed to work in particularly difficult conditions. Including under 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.

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

Chemical composition

All alloys are characterized by their specific chemical composition. Established standards determine the concentration of all elements within 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 carbon concentration leads to brittleness of the structure and problems with weldability. 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. Uneven carbon distribution results in poor performance.
3. Manganese is included in the composition of many metals, in this case it is about 0.65%.
4. Silicon largely determines the basic 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 each account for 0.3%. A low chromium concentration means that the surface can become corroded. Prolonged exposure to precipitation and some chemical substances leads to corrosion. Excessive use with such damage to the metal leads to a decrease in the strength of supporting structures and a deterioration in decorative qualities.

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

Mechanical properties

The main characteristics of steel C255 can be found in specialized 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. Tensile strength 360 MPa.
3. The relative elongation of the workpiece is 25%.

If necessary, the performance characteristics of C255 steel can be improved by heat and other types of treatment. The most common methods used are surface hardening and tempering:

1. In the first case, the surface hardness is increased. Exposure to high temperatures causes the metal structure to rearrange and become denser. To carry out 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 ensures a uniform decrease in temperature.
2. Tempering involves reducing internal stresses, which can cause surface or internal defects. This method of heat treatment involves heating to a lower temperature, but the temperature is increased and decreased gradually. Due to this, the main operational characteristics of C255 steel are increased.

Quenching and tempering in most cases are carried out when the workpiece has small sizes. Massive products are difficult to process, since heating them requires large specialized equipment.

The alloy in question is characterized by excellent mechanical properties, but it is not resistant to corrosion. That is why the structures being created require protection from moisture and some other chemicals. In most cases, the surface is double-painted with waterproof paint when the base is first primed. To significantly increase the protection of the structure, hot-dip galvanizing is carried out, since zinc can withstand exposure to moisture and chemicals.

Application area

The steel grade in question, 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 load may be placed on the structures being created:

1. Dynamic – gradual increase and decrease in pressure. To withstand dynamic loads, the metal must have ductility.
2. Moving – changing 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 load-bearing 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 that are subject to high loads. In some cases, it is allowed to use metal in the manufacture of critical mechanisms in the engineering industry.

Alloy analogues

Based on their 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 standards:

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

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

Steel marking 255

When marking C255 steel, certain standards are used that allow you to quickly determine the basic 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 markings are 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 angles, bent profiles and channels, and I-beams. The cross-sectional thickness of the manufactured elements must be no less than 4 mm and no more than 30 mm.

You may also be interested in the following articles:

Steel 10 (carbon quality)
Steel 35 structural carbon quality

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