Steel 3 – decoding, purpose, GOST, comparative characteristics

STATE STANDARD OF THE USSR UNION

By Resolution of the State Committee of Standards of the Council of Ministers of the USSR dated April 6, 1971 No. 692, the introduction date was established

from 01.01.72

Failure to comply with the standard is punishable by law

This standard applies to carbon steel of ordinary quality: hot-rolled - sectional, shaped, thick-sheet, thin-sheet, broad-band (universal) and cold-rolled - thin-sheet, and, in terms of chemical composition standards, also to ingots, blooms, slabs, rounds, rolled and cast billets from plants continuous casting of steel, pipes, forgings and stampings, strip, wire and hardware.

The standard does not apply to steel produced by the Bessemer process.

The standard takes into account the requirements of the CMEA recommendation on standardization PC 1-70.

Decoding

In accordance with GOST 380-2005, the full name of the steel is 3 st3Gsp. The brand indicates the chemical composition, serial number and degree of deoxidation.

• St means that this is a grade of steel of ordinary quality. The quality of steel is determined by the level of sulfur and phosphorus content; the lower the concentration, the higher the quality. There are ordinary, high-quality, high-quality and especially high-quality steels. The content of sulfur and phosphorus in ordinary alloys does not exceed 0.06% and 0.07%.
• Number 3 is the conditional number of the brand according to GOST. GOST 380-2005 regulates carbon steels of ordinary quality; the grade number is assigned to the alloy according to its chemical composition.
• The letter G indicates the manganese content.
• Cn degree of deoxidation of steel. Deoxidation of steel is the process of removing oxygen from it, preventing oxidation and “boiling” and the release of gas during solidification. There are calm (sp), semi-quiet (ps) and boiling (kp) steels. Strongly deoxidized steels are called calm, and weakly boiling steels. The weaker the deoxidation, the higher the porosity of the steel. St3Gsp steel is considered to be calm; it has a semi-quiet version - st3ps steel.

Steel 3

Home/Characteristics of Steel and Rolled Metal Grades/Steel 3

VSt3sp steel is used as a substitute for St3 steel. Material hardness st. 3: HB 10 -1 = 131 MPa Weldability st. 3: no restrictions Flock sensitivity of steel st. 3: not sensitive Propensity to temper brittleness: not prone

Structural carbon steel of ordinary quality St3 is used for the manufacture of load-bearing and non-load-bearing elements for welded and non-welded structures, as well as parts operating at positive temperatures. Category 5 sheet and shaped steel (up to 10mm) - for load-bearing elements of welded structures intended for operation in the range from -40 to +425 °C under variable loads.

St3 alloy contains: carbon - 0.14-0.22%, silicon - 0.05-0.17%, manganese - 0.4-0.65%, nickel, copper, chromium - up to 0.3%, arsenic up to 0.08%, sulfur and phosphorus - up to 0.05 and 0.04%, respectively.

Technological properties of steel grade st3

St3 steel is not prone to temper brittleness and is non-flock sensitive. weldability without restrictions.

The quality of structural steel is determined by corrosion resistance, mechanical properties and weldability. According to their mechanical characteristics, steels are divided into groups: regular, high-strength and high-strength steel.

The basic properties of steel directly depend on the chemical elements that make up the alloy and the technological features of production.

The basis of the steel structure is ferrite. It is low-strength and ductile, cementite, on the contrary, is brittle and hard, and perlite has intermediate properties. The properties of ferrite do not allow it to be used in building structures in its pure form. To increase the strength of ferrite, the steel is saturated with carbon (steels of normal strength, low-carbon), alloyed with additions of chromium, nickel, silicon, manganese and other elements (low-alloy steels with a high strength coefficient) and alloyed with additional thermal hardening (high-strength steels)

Harmful impurities include phosphorus and sulfur. Phosphorus forms a solution with ferrite, thus reducing the ductility of the metal at high temperatures and increasing brittleness at low temperatures. The formation of iron sulfide with an excess of sulfur leads to red brittleness of the metal. St3 steel contains no more than 0.05% sulfur and 0.04% phosphorus.

At temperatures insufficient for the formation of a ferritic structure, carbon may be released and accumulate between grains and near defects in the crystal lattice. Such changes in the steel structure reduce the resistance to brittle fracture and increase the yield strength and tensile strength. This phenomenon is called aging, due to the duration of the process of structural changes. Aging is accelerated by temperature fluctuations and mechanical stress. Gas-saturated and contaminated steels are most susceptible to aging.

Structural steels are produced by open-hearth and converter methods. The quality and mechanical properties of oxygen-converter and open-hearth steels are practically the same, but the oxygen-converter method is simpler and cheaper.

Based on the degree of deoxidation, they distinguish between calm, semi-quiet and boiling steels. Boiling steels are not deoxidized. When poured into molds, they boil and become saturated with gases. To improve the quality of low-carbon steels, deoxidizers are used - additives of silicon (0.12 - 0.3%) or aluminum (up to 0.1%). Deoxidizers bind free oxygen, and the resulting aluminates and silicates increase the number of crystallization sites, promoting the formation of a fine-grained structure. Deoxidized steels are called calm steels because they do not boil when poured. Quiet steels are more uniform, less brittle, weld better and resist dynamic loads well. They are used in the manufacture of critical structures. The use of mild steel is limited by its high cost, and for technical and economic reasons, the most common structural material is semi-mild steel. To deoxidize semi-mild steel, a smaller amount of deoxidizer, mainly silicon, is used. In terms of quality and price, semi-quiet steels occupy an intermediate position between boiling and calm steels.

From the group of low-carbon steels of ordinary power (GOST 380-71, as amended), steel grades St3 and St3Gps are used for building structures. St3 steel is produced calm, semi-calm and boiling.

Depending on the operational requirements and type of structure, the steel must meet the requirements of GOST 380-71. Carbon steel is divided into 6 categories. When supplying steel grades VSt3Gps and VSt3 of all categories, a guaranteed chemical composition, relative elongation, yield strength, tensile strength, and cold bending are required.

Toughness requirements vary by category.

When marking steel in accordance with GOST 380-71 (as amended), first put the designation of the delivery group, then the grade, degree of deoxidation and category.

According to GOST 23570-79, more stringent steel quality control and limits on arsenic and nitrogen content are established. The brand designation includes the percentage of carbon (in hundredths of a percent), the degree of deoxidation and the letter G for manganese steels.

Chemical composition

98% of the composition of St3 steel is iron. The carbon content in the composition of st3 is low. It is enough to provide hardness to the alloy, while at the same time it does not reduce the toughness of the steel and its ductility. You can also find in the composition:

• Silicon. This element is the main deoxidizer of the alloy. Thanks to it, St3 steel acquires a fine-grained structure, and it also increases strength without reducing ductility.
• Manganese. A deoxidizer that promotes the removal of sulfur. Thanks to manganese, steel improves its surface quality, steel is better welded, forged, and becomes resistant to wear.
• Sulfur. A harmful impurity that causes an increase in red brittleness and the risk of cracking during high-temperature processing.
• Phosphorus. A harmful impurity that greatly reduces the temperature range of use of steels. Due to phosphorus, steel loses its ductility at high temperatures, and at low temperatures it becomes prone to brittleness.
• Nickel, copper, chromium, nitrogen, aluminum. Elements may be present in the composition of steel 3, but do not affect its characteristics due to their insignificant concentration.

Phosphorus and sulfur have a negative impact on weldability and cause welds to become porous and prone to cracking.

Chemical composition in % of the material St3sp

GOST 380-2005

Chemical composition, % (GOST 380-2005)

Common quality carbon steel. Grades

MKS 77.080.20

OKP 08 7010

Date of introduction 2008-07-01

Preface

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic provisions" and GOST 1.2-97 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. The procedure for the development, adoption, application, updating and oUkrNIImet" of the Ukrainian State Scientific and Technical Institute; Interstate Technical Committee for Standardization MTK 327 “Rolled bars, shaped and special profiles”

2 INTRODUCED by the State Committee of Ukraine on Technical Regulation and Consumer Policy

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 28 of December 9, 2005)

The following voted for the adoption of the standard:

4 Appendix B of this standard complies with international standards:

• ISO 630:1995 “Structural steels. Rolled thick sheets, wide flats, long and shaped profiles" (ISO 630:1995 "Structural steels - Plates, wide flats, bars, sections and profiles", NEQ);
• ISO 1052:1982 “Steels for general engineering purposes” (NEQ) regarding requirements for the chemical composition of steel

5* By Order of the Federal Agency for Technical Regulation and Metrology dated July 20, 2007 N 185-st, the interstate standard GOST 380-2005 was put into effect as a national standard of the Russian Federation on January 1, 2008.

* By Order of the Federal Agency for Technical Regulation and Metrology dated March 7, 2008 N 33-st, the deadline for introducing the interstate standard GOST 380-2005 was postponed to July 1, 2008.

6 INSTEAD GOST 380-94

7th EDITION (September 2009) as amended (8-2008).

Information on the entry into force (termination) of this standard is published in the “National Standards” index.

Information about changes to this standard is published in the “National Standards” index, and the text of the changes is published in the “National Standards” information indexes. In case of revision or cancellation of this standard, the relevant information will be published in the information index “National Standards”

AMENDED Change No. 1, approved and put into effect by Order of Rosstandart dated December 29, 2015 N 2206-st from 04/01/2016

Change No. 1 was made by the database manufacturer according to the text of IMS No. 4, 2016

1 area of ​​use

This standard applies to carbon steel of ordinary quality, intended for the production of hot-rolled products: long, shaped, thick sheets, thin sheets, wide strip and cold rolled thin sheets, as well as ingots, blooms, slabs, rounds, rolled and continuously cast billets, pipes, forgings and stampings, strips , wire, hardware, etc.

2 Normative references

This standard uses normative references to the following interstate standards:

GOST 7565-81 (ISO 377-2-89) Cast iron, steel and alloys. Sampling method for determining chemical composition

GOST 7566-94 Metal products. Reception, labeling, packaging, transportation and storage

GOST 12359-99 (ISO 4945-77) Carbon steels, alloyed and high-alloyed. Methods for determining nitrogen

GOST 17745-90 Steels and alloys. Gas determination methods

GOST 18895-97 Steel. Photoelectric spectral analysis method

GOST 22536.0-87 Carbon steel and unalloyed cast iron. General requirements for analysis methods

GOST 22536.1-88 Carbon steel and unalloyed cast iron. Methods for determining total carbon and graphite

GOST 22536.2-87 Carbon steel and unalloyed cast iron. Methods for determining sulfur

GOST 22536.3-88 Carbon steel and unalloyed cast iron. Phosphorus determination methods

GOST 22536.4-88 Carbon steel and unalloyed cast iron. Methods for determining silicon

GOST 22536.5-87 (ISO 629-82) Carbon steel and unalloyed cast iron. Methods for determining manganese

GOST 22536.6-88 Carbon steel and unalloyed cast iron. Arsenic determination methods

GOST 22536.7-88 Carbon steel and unalloyed cast iron. Methods for determining chromium

GOST 22536.8-87 Carbon steel and unalloyed cast iron. Methods for determining copper

GOST 22536.9-88 Carbon steel and unalloyed cast iron. Methods for determining nickel

GOST 22536.10-88 Carbon steel and unalloyed cast iron. Methods for determining aluminum

GOST 22536.11-87 Carbon steel and unalloyed cast iron. Methods for determining titanium

GOST 27809-95 Cast iron and steel. Spectrographic analysis methods

GOST 28033-89 Steel. X-ray fluorescence analysis method

Note - When using this standard, it is advisable to check the validity of the reference standards using the “National Standards” index compiled as of January 1 of the current year, and according to the corresponding information indexes published in the current year. If the reference standard is replaced (changed), then when using this standard you should be guided by the replacing (changed) standard. If the reference standard is canceled without replacement, then the provision in which a reference is made to it is applied in the part that does not affect this reference.

3 Steel grades

3.1 Carbon steel of ordinary quality is produced in the following grades: St0, St1kp, St1ps, St1sp, St2kp, St2ps, St2sp, St3kp, St3ps, St3sp, St3Gps, St3Gsp, St4kp, St4ps, St4sp, St5ps, St5sp, St5Gps, St6ps, St6sp.

The letters “St” mean “Steel”, the numbers are the conventional number of the brand depending on the chemical composition, the letter “G” is manganese when its mass fraction in steel is 0.80% or more, the letters “kp”, “ps”, “sp” " - degree of deoxidation of steel: "kp" - boiling, "ps" - semi-calm, "sp" - calm.

3.2 A comparison of steel grades according to this standard and international standards ISO 630 and ISO 1052 is given in Appendix A.

3.3 Requirements for the chemical composition of steel grades E 185 (Fe 310), E 235 (Fe 360), E 275 (Fe 430), E 355 (Fe 510), Fe 490, Fe 590, Fe 690 according to international standards ISO 630 [1 ] and ISO 1052 [2] are given in Appendix B.

3.4 The degree of deoxidation, if it is not specified in the order, is established by the manufacturer.

4 Requirements for the chemical composition of steel

4.1 The chemical composition of steel (main elements) according to the analysis of the ladle sample must comply with the standards specified in Table 1.

Table 1

In percentages

4.2 It is allowed to manufacture steel of all grades, except for those intended for rolled products used in shipbuilding and car building, without limiting the lower limit of the mass fraction of carbon and manganese, provided that the required level of mechanical properties is ensured.

In steel grades St2kp, St3kp and St4kp, intended for the production of long and shaped steel, it is allowed to increase the mass fraction of silicon to 0.07%.

(Changed edition, Amendment No. 1).

4.3 When deoxidizing semi-quiet steel with aluminum, titanium or other deoxidizing agents that do not contain silicon, as well as several deoxidizing agents (ferrosilicon and aluminum, ferrosilicon and titanium, etc.), the mass fraction of silicon in the steel is allowed less than 0.05%. Deoxidation with titanium, aluminum and other deoxidizing agents that do not contain silicon is indicated in the quality document.

4.4 The mass fraction of chromium, nickel and copper in steel of all grades, except St0, should be no more than 0.30% each. In steel grade St0, the mass fraction of chromium, nickel and copper is not standardized.

In steel produced by the scrap process, a mass fraction of copper up to 0.40%, chromium and nickel - up to 0.35% each are allowed. At the same time, in steel grades St3kp, St3ps, St3sp, St3Gps and St3Gsp, the mass fraction of carbon should be no more than 0.20%.

4.5 The mass fraction of sulfur in steel of all grades, except St0, should be no more than 0.050%, phosphorus - no more than 0.040%. In steel grade St0, the mass fraction of sulfur should be no more than 0.060%, phosphorus - no more than 0.070%.

4.6 The mass fraction of nitrogen in steel should be no more than:

• smelted in electric furnaces - 0.012%;
• open hearth and converter - 0.010%.

It is allowed to increase the mass fraction of nitrogen in steel to 0.013%, provided that the norm of the mass fraction of phosphorus according to 4.5 is reduced by no less than 0.005% for each increase in the mass fraction of nitrogen by 0.001%.

4.7 The mass fraction of arsenic in steel of all grades, except St0, should be no more than 0.080%. The mass fraction of arsenic in steel grade St0 is not standardized.

4.8 Maximum deviations for the chemical composition of finished rolled products, ingots, billets, forgings and further processing products must comply with the standards specified in Table 2.

table 2

In percentages

Note - For chemical elements, the mass fraction of which, according to 4.2, is limited only by the upper limit, plus maximum deviations are used.

(Amendment); (Changed edition, Amendment No. 1).

5 Control methods

5.1 Sampling methods for determining the chemical composition of steel - according to GOST 7565.

5.2 Chemical analysis of steel - according to GOST 12359, GOST 17745, GOST 18895, GOST 22536.0 - GOST 22536.11, GOST 27809, GOST 28033 or other methods approved in the prescribed manner and ensuring the necessary accuracy.

If disagreements arise between the manufacturer and the consumer, the assessment is carried out using the control methods provided for in this standard.

5.3 Determination of the mass fraction of chromium, nickel, copper, arsenic, nitrogen, and also silicon in boiling steel may not be carried out, provided that the manufacturer guarantees that the standards are met.

6 Marking

6.1 Marking of products made of carbon steel of ordinary quality is carried out according to regulatory documents for a specific type of metal product, taking into account the requirements of GOST 7566.

At the request of the consumer or if there are requirements for color marking in the regulatory documents for rental, it is additionally applied with indelible paint in the colors indicated in Table 3.

Table 3

Appendix A (for reference). Designation of steel grades according to this standard and international standards ISO 630:1995, ISO 1052:1982

Appendix A (reference)

Table A.1

Appendix B (recommended). Requirements for steel according to international standards ISO 630:1995, ISO 1052:1982

Appendix B (recommended)

B.1 The chemical composition of steel according to the analysis of the ladle sample must comply with the standards given in Table B.1

Table B.1

Note 1 - The sign “-” means that the indicator is not standardized.

Note 2 - NE - non-boiling steel.

Note 3 - GF is a fine grain mild steel. The recommended mass fraction of total aluminum is not less than 0.020%.

B.2 Steel grades Fe 490, Fe 590 and Fe 690 are made semi-quiet and calm.

B.3 Maximum deviations of the chemical composition in finished rolled products must correspond to those given in Table B.2.

Table B.2

In percentages

Purpose

Steel 3 and other alloys of this class are superior in scope to all other types of steel. It is used for the production of forged products, fences, gates, and decorative elements. In construction as a material for load-bearing, non-load-bearing, welded and non-welded building structures. Pipes and fittings, parts of mechanisms for operation at positive temperatures are made from it. St3 steel is used in the chemical, oil and gas industries, as well as in mechanical engineering.

Due to its simple chemical composition, availability, performance characteristics, and physical properties, steel 3 is one of the most common materials in industries that require a lot of steel. For example, in the construction of railways and pipelines for transporting natural gas or water.

III. Acceptance rules

18. Product quality checks during manufacturing and acceptance of finished products are carried out by the technical control department (QC) of the manufacturer. The quality control department checks the compliance of the dimensions, appearance, mechanical properties and chemical composition of steel with the standards specified in the relevant standards and departmental technical specifications.

Control and acceptance of products are carried out by the quality control department based on observations of the steel production process, records of test results carried out during its manufacture, and tests of finished products.

19. Steel of groups A and B is supplied either as whole heats or parts of heats, depending on the batch sizes and order conditions. For steel grades St.0, MSt.0 and BSt.0, float delivery is not required.

20. Lot sizes and the number of samples for testing are established in special standards or departmental technical specifications for individual types of rolled products.

21. In the event of an unsatisfactory result of any test, this test may be repeated, for which a double number of samples are taken. If the results of re-testing the steel are unsatisfactory, the manufacturer is given the right to subject the delivered batch to normalization or annealing and re-sorting and present it for delivery again.

Advantages and disadvantages

The main distinguishing feature of St3 steel is its combination of positive characteristics or versatility. This means that it does not have any one key advantage, it shows decent characteristics from all sides, which makes it the first on the market. This steel is not intended for highly specialized applications in special conditions, but is ideal for a wide range of everyday applications.

The disadvantages of steel include low performance at low temperatures.

Advantages of steel st3Gsp:

1. homogeneous structure, due to which the steel becomes homogeneous, ductile and protected from adverse environmental influences;
2. resistance to atmospheric corrosion;
3. high elasticity and hardness;
4. insensitivity to flakes;
5. impact strength, allowing to withstand dynamic loads well;
6. not subject to temper brittleness;
7. simple production process, no expensive alloying additives;
8. relatively low cost.

Separately, it should be mentioned that the material is perfectly weldable. It can be carried out using any known technology without preliminary and subsequent treatments.

Characteristics

St3 is characterized as carbon structural steel of ordinary quality. Steel does not contain alloying additives that protect it from external influences. For use in aggressive chemical environments or conditions of high humidity, it is necessary to coat the steel with a protective layer. St3 has good weldability, high strength, and resists loads well, which allows it to be used in load-bearing structures. The price of St3 steel is optimal for the construction of facilities or laying communications that require a large amount of metal. Density St3 - 7850 kg/m3.

I. Classification

Assortment

• Channels are parallel (P), with sloped flanges (U), equal-flange bent;
• round sections circle and reinforcement;
• VGP pipes, electric welded (ES), seamless (BGD);
• I-beams, wide-flange, column, special, with flange slopes;
• steel square;
• corners equal and unequal;
• square and rectangular profile;
• sheet steel: hot-rolled, corrugated, expanded metal, strip.

Types of delivery

• Hot rolled sheets, including strip and tape;
• forgings;
• rails;
• pipes;
• rod and wire.

Substitutes

A substitute is an alloy that is closest in performance characteristics to the main one. Substitutes for St3 are usually one of three domestic brands: S245, S285, VSt3Sp.

It is acceptable to use foreign analogues that differ in markings, but are available in any corner of the world map. They are:

IN THE USA:

• A57036;

In Great Britain:

• 40B;
• 722M24;

In Germany:

• 0038;

In France:

• E24-2;
• E24-4.

In Japan:

• SS330;
• In Italy:
• Fe360B;

In China:

In Austria:

In Hungary

Comparison with alloy structural steels

Steel st3 is a carbon structural steel of ordinary quality. It is used to produce welded and non-welded structures, heavily loaded trusses and other load-bearing elements. St3 is resistant to atmospheric corrosion, but without a protective coating it will deteriorate upon prolonged contact with moisture or an aggressive chemical environment.

Alloy structural steel is protected from corrosion by alloying elements, so it can be used without a protective layer when in contact with moisture and aggressive environments. Alloy steel is more difficult to produce, more expensive and more prone to brittleness. The processing of such steel may require special conditions, while the more affordable and easier to produce steel 3 does not require any special processing conditions.

Comparison with alloy tool steels

Alloy tool steel is used in the production of tools. Alloying additives are aimed at improving the quality of steel, thanks to them it is possible to achieve a significant advantage over carbon alloys. These include:

• red fastness;
• high hardenability;
• resistance to impact loads (especially important for impact tools);
• wear resistance.

St3 steel is structural and, as a rule, is not used for the manufacture of moving parts of tools.

Foreign analogues

Technological properties

Technological properties of the material St3sp.

Temperature of critical points, °C

Standardized indicators of St3sp steel by rolled category (GOST 535-2005)

Parameters for the use of electric-welded straight-seam pipes made of St3sp steel (GOST 32569-2013)

Parameters for the use of electric-welded spiral-welded pipes made of St3sp steel (GOST 32569-2013)

Application of St3sp steel for fasteners (GOST 32569-2013)

Conditions for using St3sp steel for bodies, covers, flanges, membranes and valve assembly made from rolled products, forgings (stampings) (GOST 33260-2015)

Resistance of structural materials against crevice erosion (GOST 33260-2015)

NOTE. The coefficient of erosion resistance of a material is the ratio of the rate of erosive wear of the material to the rate of erosive wear of steel 12Х18Н10Т (taken as 1).

Mechanical properties of rolled products under tension, as well as cold bending test conditions (GOST 535-2005)

NOTE

1. By agreement between the manufacturer and the consumer, the following is allowed:
   reduction in yield strength by 10 N/mm2 (1 kgf/mm2) for shaped steel with a thickness of over 20 mm;
2. reduction in relative elongation by 1% (abs.) for shaped rolled products of all thicknesses.
3. It is allowed to exceed the upper limit of tensile strength by 49.0 N/mm2 (5 kgf/mm2), and by agreement with the consumer - without limiting the upper limit of tensile strength, provided that other standards are met. At the request of the consumer, exceeding the upper limit of temporary resistance is not allowed.

Impact strength of rolled products (GOST 535-2005)

NOTE

• The “-” sign means that the indicator is not standardized.
• Determination of the impact strength of round rolled products is carried out starting from a diameter of 12 mm, square - starting from the square side of 11 mm.
• It is allowed to reduce the value of impact strength on one sample by 30%, while the average value must not be lower than the standards specified in this table.
• Impact strength KCV is determined for rolled products with a thickness of up to 20 mm inclusive.

Stamps

1.1. Depending on the purpose, steel is divided into three groups:

A - supplied according to mechanical properties;

B - supplied according to chemical composition;

B - supplied according to mechanical properties and chemical composition.

1.2. Depending on the standardized indicators, steel of each group is divided into categories:

groups A - 1, 2, 3;

groups B - 1, 2;

Groups B - 1, 2, 3, 4, 5, 6.

Note. These categories do not apply to steel with a thickness of less than 4 mm.

1.3. Steel is produced in the following grades:

groups A - St0, St1, St2, St3, St4, St5, St6;

Group B - BSt0, BSt1, BSt2, BSt3, BSt4, BSt5, BSt6;

Group B - VSt1, VSt2, VSt3, VSt4, VSt5.

1.4. Steel of all groups with grade numbers 1, 2, 3 and 4 according to the degree of deoxidation is produced boiling, semi-calm and calm, with numbers 5 and 6 - semi-calm and calm.

Semi-quiet steel with grade numbers 1 - 5 is produced with normal and high manganese content.

Steel grades St0 and BSt0 are not distinguished by the degree of deoxidation.

pp. 1.2

—
1.4.
(Changed edition, IUS 6 -
74).
1.4.1. The degree of deoxidation of all groups is selected by the manufacturer, if it is not specified in the order.

1.5. Steel grades VSt1, VSt2, VSt3 of all categories and all degrees of deoxidation, including with a high content of manganese, and at the request of the customer, steel grades BSt1, Bst2, BSt3 of the second category of all degrees of deoxidation, including with a high content of manganese, are supplied with a guarantee of weldability.

(Changed edition, IUS 6

—
74).
1.5.1. Weldability is ensured by manufacturing technology and compliance with all chemical composition requirements for steel of groups B and C.

1.5.2. The supply of group B steel with a guarantee of weldability is specified in the order and in the certificate.

1.5.3. Steel with a carbon content in the finished product of more than 0.22% is used for welded structures under welding conditions that ensure the reliability of the welded joint.

pp. 1.5.1 - 1.5.3. (Changed edition, IUS 6-74).

1.6. The designation of steel grades when ordering, branding, in a certificate, on drawings and in other documentation is alphanumeric.

1.6.1. The letters St mean “steel”, numbers from 0 to 6 are the conditional number of the brand depending on the chemical composition of the steel and mechanical properties, for example: St0, St1, St2, St3.

1.6.2. The letters B and C in front of the brand designation indicate the steel group; group A is not indicated in the steel grade designation, for example: BSt3, VSt3, St3.

1.6.3. To indicate the degree of deoxidation, indices are added to the designation of the steel grade after the grade number: kp - boiling, ps - semi-quiet, sp - calm, for example: St3kp, St3ps, St3sp, BSt3sp, VSt3sp.

1.6.4. To designate a steel category, the number of the corresponding category is added to the brand designation at the end, for example: St3ps2, BSt3kp2, VSt4ps2.

1.6.5. The first category is not indicated in the steel grade designation, for example: BSt3kp, VSt3ps.

1.6.6. When ordering steel of the required category without indicating the degree of deoxidation in the designation of the steel grade, the grade number and category are separated from each other by a dash, for example: St3-2, BSt3-2.

1.6.7. To designate semi-mild steel with a high manganese content, the letter G is added to the designation of the steel grade after the grade number, for example: St3Gps, VSt3Gps, VSt3Gps3.

1.6.8. When branding, it is allowed to use letters and numbers of the same height.

When hot stamping rolled steel, the steel marking may be indicated without indicating the group and category of steel and indicating them in the certificate. Groups and categories of steel are applied by agreement of the parties.

(Changed edition, IUS 6-74).

1.6.9.
(Excluded, IUS 6-74).
1.6.10. Steel grade BSt3sp (in ingots and slabs), intended for rolling into sheet metal, supplied under group B categories 4 - 6, must meet the requirements of clause 2.4.5.

(Introduced additionally, IUS 6-74).

Mechanical properties

Mechanical properties of rolled products

Mechanical properties of forgings

Impact strength KCU (GOST 380-94)

Mechanical properties at elevated temperatures

Endurance limit

TECHNICAL REQUIREMENTS

2.1. In terms of shape, dimensions, permissible deviations, surface condition and other technical requirements not provided for by this standard, steel must meet the requirements of the relevant standards for rolled products of certain types.

2.2. Group A steel.

2.2.1. Standardized indicators for steel group A are shown in table. 1.

Table 1

Notes

1. For steel grade St6, cold bending is not standardized.

2 The “+” sign means that the indicator is normalized, the “-” sign means that the indicator is not normalized.

3. For category 3 steel supplied for the manufacture of pipes, cold bending is not standardized.

table 2

Table 2. (Changed edition, Amendment No. 4).

Notes:

1. It is allowed to exceed the upper limit of tensile strength by 3 kgf mm-2 compared to the specified, provided that other standards are met, and with the consent of the customer - without limiting the upper limit.

2. For sheet and wide steel of all thicknesses and shaped steel with a thickness of over 20 mm, the value of the yield strength is allowed to be 1 kgf mm-2 lower than that specified.

3. For sheet steel with a thickness of 8 to 4 mm, a reduction in elongation by 1 abs is allowed. % for each millimeter of thickness reduction. Standards for relative elongation for sheets with a thickness of less than 4 mm are established by the relevant standards.

4. It is allowed to reduce the relative elongation for sheet, wide and shaped steel of all thicknesses by 1 abs. %.

5. For periodic profile reinforcing steel grades VSt6ps, VSt6sp with a thickness of up to 40 mm, the yield strength must be at least 30 kgf mm-2.

7. Standards for cold bending until the sides are parallel are established when testing longitudinal samples; when testing transverse samples, the size of the mandrel increases by 0.5 a

.

(Introduced additionally, Amendment No. 4).

pp. 2.2.1, 2.2.2. (Changed edition, IUS 6-74).

2.2.2. The mechanical properties of steel in tension, as well as the test conditions for bending at 180° in a cold state, must comply with the standards specified in table. 2.

2.2.3. The chemical composition of steel is not regulated, but is indicated in the certificate.

2.3. Group B steel

2.3.1. Standardized indicators for group B steel are shown in table. 3.

Table 3

Notes:

1. For steel grade BSt0, only the content of carbon, phosphorus and sulfur is standardized.

2. The “+” sign means that the indicator is normalized, the “-” sign means that the indicator is not normalized.

2.3.2. The chemical composition of steel according to heat analysis of a ladle sample must comply with the standards specified in table. 4.

2.3.3. Permissible deviations in the chemical composition of finished products from the standards specified in table. 4, must correspond to those indicated in table. 5.

pp. 2.3.2 - 2.3.3. (Changed edition, IUS 6-74).

2.3.4. Chemical analysis of finished rolled products at the manufacturing enterprise may not be carried out if the manufacturing enterprise ensures compliance with established standards.

2.3.5. Chemical analysis of steel of all degrees of deoxidation for the content of chromium, nickel, copper, arsenic, nitrogen, and boiling steel also for silicon content may not be carried out if the manufacturer ensures compliance with established standards.

In steel smelted from Kerch ores, determination of arsenic content is mandatory.

Table 4

Notes:

1. In steel smelted from Kerch ores, arsenic content is allowed up to 0.15%, phosphorus - up to 0.050%.

2. When deoxidizing semi-quiet steel with aluminum, titanium or other deoxidizing agents that do not contain silicon, as well as several deoxidizing agents (ferrosilicon and aluminum, ferrosilicon and titanium, etc.), the silicon content in the steel is allowed less than 0.05%. Deoxidation with titanium, aluminum and other deoxidizing agents that do not contain silicon is indicated in the certificate.

3. For rolled steel with grade numbers 3, 4, 5, 6 (all degrees of deoxidation), thickness up to 12 mm incl. a reduction in manganese content by 0.10% is allowed.

4. The nitrogen content in finished rolled products, as well as in ingots, blooms, slabs, strips and billets intended for further rolling, made of oxygen-converter and open-hearth steel should be no more than 0.008%.

5. For boiling chemically sealed steel in finished rolled products, a silicon content of up to 0.15% is allowed, with the exception of cases where the steel is intended for cold heading and drawing or stamping, which must be specified in the order.

Table 5

Note. In steel grades BSt3 of all degrees of deoxidation and BSt3Gps, supplied at the customer’s request with a guarantee of weldability, positive deviations in carbon are not allowed.

2.4. Group B steel

2.4.1. Standardized indicators for steel group B are shown in table. 6.

Table 6

Notes:

1. Steel categories 3, 4, 5 and 6 are supplied semi-calm and calm. By agreement of the parties, it is allowed to supply boiling steel grades VSt3 and VSt4 of category 3, while the standards of impact strength at plus 20 °C are adopted in accordance with the standards of Table. 7 for mild and semi-quiet steel grades VSt3 and VSt4.

2. The “+” sign means that the indicator is normalized, the “-” sign means that the indicator is not normalized.

3 For steel categories 1, 2 and 3 supplied for the manufacture of pipes, cold bending is not standardized.

(Changed edition, IUS 6-74).

2.4.2. The mechanical properties of steel in tension and the test conditions for 180° bending in a cold state must comply with the standards specified for group A steel in Table. 2.

2.4.3. The impact strength of steel grades VSt3ps, VSt3sp, VSt3Gps categories 3, 4, 5 and 6 and steel grades VSt4ps, VSt4sp, VSt4Gps category 3 must comply with the standards specified in table. 7.

Table 7

Notes:

1. The sign “-” means that the rolled products are not tested for impact strength.

2 The impact strength of round steel is determined from a diameter of 12 mm, square steel - starting from the square side of 11 mm, shaped steel from thicknesses from which a test sample can be cut in accordance with GOST 9454-78.

2.4.4. In terms of chemical composition, group B steel must comply with the standards specified for group B steel in table. 4, except for the lower limit on carbon content. Deviation from the lower limit for carbon content is not a rejection sign. The upper limit of manganese content is allowed 0.2% higher than indicated in the table. 4 for all steel grades, except for grades VSt1Gps, VSt2Gps, VSt3Gps, VSt4Gps, VSt6Gps.

At the consumer's request, the sulfur content in group B steel should be no more than 0.040%.

2.4.5. Deoxidation of VSt3sp grade steel of categories 4 - 6, intended for sheet metal, is carried out with aluminum, and complex deoxidation with other deoxidizers and nitride-forming elements is also allowed. The content of residual (acid-soluble) aluminum in steel must be at least 0.02%. In case of complex deoxidation, it is allowed not to determine the residual aluminum, but to carry out impact strength tests after mechanical aging on 4 sheets or 2 rolls from the batch. The deoxidizers used are indicated in the certificate.

2.4.6. In steel of categories 4 - 6, smelted on the basis of Kerch ores, the arsenic content should be no more than 0.15%, and at the request of the consumer - no more than 0.08%. The phosphorus content should not exceed 0.05% for steel of 1 - 3 categories and 0.04% for 4 - 6 categories.

pp. 2.4.3 - 2.4.6. (Changed edition, IUS 6-74).

2.4.7. In steel grade VSt6ps for periodic profile reinforcement with a diameter of 10 to 28 mm incl. carbon content should be. 0.30 - 0.39%, manganese 0.6 - 0.9%, and with a diameter of more than 28 mm - 0.28 - 0.37% and 0.8 - 1.1%, respectively.

2.4.8. Permissible deviations in the chemical composition of finished rolled products from the standards provided for in clause 2.4.4 must correspond to those indicated in table. 5, with the exception of positive deviations for carbon, which are not allowed for VSt3 steel of all degrees of deoxidation and for VSt3Gps steel.

The content of sulfur and phosphorus in finished rolled products should not exceed 0.055 and 0.045%, respectively.

In steel smelted from Kerch ores, the phosphorus content in the finished product should not exceed 0.045% for categories 4, 5, 6 and 0.055% for categories 1, 2, 3; sulfur no more than 0.055% for all categories.

2.4.9. Chemical analysis of finished rolled products in the absence of customer requirements, as well as chemical analysis of steel of all degrees of deoxidation for chromium, nickel, copper, arsenic, nitrogen, and boiling steel for silicon content may not be performed if the manufacturer ensures compliance with established standards.

pp. 2.4.8, 2.4.9. (Changed edition, IUS 6-74).