Steel 45 – chemical composition, explanation, types of supply, analogues


Decoding

The marking of steel 45 contains information about the active chemical composition, the quality of the material in terms of the content of harmful impurities and the degree of deoxidation.

The word “steel” means that the alloy is of high quality. The quality of the alloy is determined by the level of sulfur and phosphorus in the composition. Sulfur and phosphorus are harmful impurities; they form undesirable compounds with iron, which adversely affect the integrity of the metal structure, lead to increased brittleness at high and low temperatures (red brittleness and cold brittleness), and negatively affect the general properties of the metal. The less phosphorus and sulfur in the steel composition, the higher the quality. Alloys are distinguished by quality:

  • ordinary quality (st);
  • high-quality (steel);
  • high quality (A);
  • especially high quality (Ш).

The number 45 indicates the percentage of carbon content in hundredths (0.45%). Carbon is the main structure-forming element in unalloyed carbon steels. By adjusting the carbon content, a significant difference in the properties of the alloy can be achieved. High carbon content gives steel strength and hardness, but reduces ductility and toughness. High-carbon steels withstand static loads well, are not prone to deformation, exhibit high strength indicators and are best suited for the manufacture of rigid building structures, such as load-bearing trusses. Low carbon steels are more suitable for structures subject to impact loads because... they are not prone to brittleness and exhibit high rates of fluidity, impact strength and elasticity. Steels with a low carbon content perform best in processing; they are better at welding, cutting and bending, and are less prone to brittleness, brittleness, and cracking.

Sp (not indicated in this case) means the calm state of steel as a result of a high degree of deoxidation. Deoxidation is the process of removing gases (mainly oxygen and nitrogen) during the solidification stage of the alloy. The higher the level of deoxidation, the fewer bubbles and gas pockets are formed on the surface and in the structure of the metal during its production. Quiet alloys (sp or without an index) have the least porous structure, semi-quiet alloys have an average porosity (ps), and boiling alloys (kp) have the largest number of bubbles. Deoxidation is ensured by introducing a deoxidizer additive into the composition, which binds undesirable elements, preventing gas formation. The most commonly used are manganese and silicon.

The composition of alloy 45 includes chemical elements not indicated in the marking; their quantity is insignificant and does not in any way affect the properties of the metal.

Temperature of critical points of steel 45

As previously noted, to improve the performance properties of the metal, heat treatment is carried out. It involves exerting a certain influence on the structure, after which the crystal lattice is rearranged and the qualities change. When carrying out heat treatment, critical points are often taken into account. Processing of steel St 45 is carried out taking into account the following factors:

  1. Temperature conditions. It is important to choose the right temperature, since too low will cause incomplete heating of the structure and complete restructuring of the structure will not occur. Too high an indicator causes overheating of the metal, as well as the appearance of scale. A variety of settings can be used to ensure that the required temperature is applied. An example would be blast furnaces or electrical installations. Melting temperatures that are too high determine that it is quite difficult to harden the steel in question at home.
  2. Rate of temperature increase. The heating rate can also determine which qualities will be transferred to the processed product. Modern equipment allows you to control the heating rate with high precision. For example, HDTVs have an electronic control unit; electrical energy is converted into magnetic energy, which causes heating of the structure.
  3. The length of time between exposure to different temperatures. When heat treating all metals, the presence of three critical points is taken into account and taken into account. The holding time may depend not only on the chemical composition of the material, but also on the size and shape of the workpiece.
  4. Features of the cooling process. The quality of the resulting product largely depends on the conditions under which the cooling process took place. For example, it is possible to use oil or water, as well as various powders as a cooling medium.

Quite often, HDTV is used to change the qualities of a metal. It is characterized by high efficiency in application, as well as ease of use. Today there are models that, if desired, can be installed in a home workshop.

Critical points are considered to be temperatures at which restructuring of the structure occurs. There are three main temperature points that are displayed on the plotted diagram.

Attention is also paid to choosing a more suitable cooling medium. For example, it is possible to carry out cooling in water. However, such an environment leads to uneven cooling, which leads to scale and other problems. For higher quality, oil is used. Large workpieces can be cooled in the open air, since it takes a long time to reduce the temperature.

Application

The range of products made from steel grade 45 is very wide, this is due to the properties of the metal, ease of production and prevalence in the domestic market. High-strength parts are produced from this steel, such as:

  • cylinders;
  • spindles;
  • cams;
  • bandages;
  • trunnions;
  • pump rolling pins;
  • pins;
  • clamps and keys of drilling rigs;
  • thrust screw;
  • sprocket wheels for drilling drawworks;
  • bevel and ordinary gears;
  • preventer rollers;
  • subs for drilling and working pipes;
  • core bit bodies;
  • barrels and swivel subs;
  • compressors;
  • rotors;
  • mud pump crosshead pins;
  • centrifugal pump shafts;
  • mud pump rods;
  • sucker rod couplings;
  • gear shafts.

The main consumers of steel 45 are the oil production, mining, and engineering industries.

Steel 45. Application in production.

Steel 45 belongs to structural carbon quality steels. Due to its high endurance and tolerance to significant temperature changes, steel 45 is used in the production of gearboxes. Gear shafts and gears are made from this steel for such mass products from our catalog as gearboxes RM-250, RM-350, RM-400, RM-500 and RM-850. Steel 45 is a relatively cheap metal, which makes it possible to produce chain drive sprockets from it. After appropriate heat treatment, sprockets for PR-25.4, PR-31.75, PR-38.1, PR-44.45 and PR-50.8 chains ensure long-term operation of the chain drive.

Advantages and disadvantages

Each alloy has individual characteristics that are most in demand in its main area of ​​application. Universal alloys are quite rare, while universality is usually called a good price-quality ratio compared to analogues, and not the breadth of material properties. The advantages and disadvantages of steel 45 determine its position on the market, the specifics of its application and outline the range of problems solved with its help.

Pros:

  1. resistance to intense loads, impacts and friction;
  2. possibility of operation in severe weather conditions;
  3. high endurance limit;
  4. good tolerance to temperature changes;
  5. low production cost;
  6. ease of machining;
  7. low sensitivity to flakes;
  8. not subject to temper brittleness;
  9. retains properties at temperatures up to 600C.

Minuses:

  1. loses strength when heated above 200C;
  2. weldability is limited;
  3. the material is susceptible to corrosion.

Steel 45

A huge number of different steels are supplied to production lines, which are characterized by their specific properties. An example is the material steel 45, which is widely used. This steel is characterized by certain performance qualities that are worth considering. GOST for steel 45 determines the concentration of all chemicals. The grade is characterized by a relatively low cost, and the decoding of the steel grade determines its wide distribution. Let's take a closer look at the features of this offer.

Why harden

The purpose of the hardening procedure is to improve the characteristics of the outer layer of metal and thus extend the service life of the product. Thanks to hardening, steel acquires the following qualities:

  1. Increased hardness and strength. Allows loaded parts, such as springs and springs, to withstand heavy loads.
  2. Increased wear resistance. Allows you to extend the life of parts by reducing abrasion or fatigue.
  3. No brittleness after heat treatment. Because Only the surface of the product is subjected to hardening, the middle remains soft.

About steel processing 45

In mechanical engineering, grade 45 steel is first heat treated. After normalization, any mechanical “decor” (milling, turning) is simpler and easier. This is how various shafts, gears, cylinders, spindles, and cams are obtained.

After finishing heat treatment or hardening, the completed parts can “boast” greater resistance to wear. At the exit, they are cooled in water and subjected to low-temperature tempering (200-300 o C), the hardness indicators are about 50 HRC.

Types of delivery

GOST 51245-99;
B03 - Metal forming. Forgings GOST 8479-70;
B22 – Long and shaped rolled products GOST 5422-73; GOST 2591-2006; GOST 2879-2006; GOST 9234-74; GOST 8319.0-75; GOST 11474-76; GOST 1133-71; GOST 8320.0-83; GOST 2590-2006;
B23 - Sheets and strips GOST 82-70; GOST 14918-80; GOST 19903-74; GOST 16523-97; GOST 103-2006;
B24 - Tapes GOST 3560-73;
B32 – Long and shaped rolled products GOST 8560-78; GOST 1050-88; GOST 14955-77; GOST 10702-78; GOST 1051-73; GOST 8559-75; GOST 7417-75;
B33 - Sheets and strips GOST 4405-75; GOST 1577-93;
B34 - Tapes GOST 2284-79;
B62 — Steel pipes and connecting parts for them GOST 8645-68; GOST 8642-68; GOST 20295-85; GOST 8644-68; GOST 12132-66; GOST 23270-89; GOST 9567-75; GOST 8646-68; GOST 13663-86; GOST 24950-81; GOST 8638-57; GOST 21729-76; GOST 53383-2009; GOST 3262-75; GOST 8734-75; GOST 8639-82; GOST 8731-87; GOST 8732-78; GOST 8733-74;
B71 – Low carbon steel wire GOST 1526-81; GOST 5663-79; GOST 792-67;
B72 – Medium and high carbon steel wire GOST 9389-75; GOST 9850-72; GOST 3920-70; GOST 3110-74; GOST 7372-79; GOST 9161-85; GOST 26366-84;
B76 – Metal mesh GOST 3306-88; GOST 51568-99;

Melting point of steel 45

Steel 45 in stock. Shipment of rental products on the day of payment in batches of any size.

Description

Steel 45 GOST stands out among similar products by a number of the following characteristics: purpose and functionality, chemical composition of elements, possible substitutes, suppliers, maximum operating temperature, foundry and technical set of characteristics. In terms of basic properties, its main substitutes are distinguished: steels 40Х, 50 and 50Г2. In terms of their characteristics, they are the closest with a similar set of functions.

Mechanical properties at T=20oC

AssortmentsTd5yKCUThermal change
MPaMPa%%kJ/m2
Pipes, GOST 8731-8758832314
The rod is calibrated, GOST 10702-7859040Annealing
Rolled products, GOST 1050-886003551640Normalization
Rolled products cold-hardened, GOST 1050-88640630
Rolled products annealed, GOST 1050-885401340
Annealed tape, GOST 2284-79440-69014
Cold-worked tape, GOST 2284-79690-1030
Strip, GOST 1577-936003551640Normalization

Characteristics and application of steel 45: high strength indicator and technical characteristics

Steel is a wrought alloy of iron (forgeable) with carbon and other elements. It is obtained from a composition in which there is room for cast iron and steel scrap, and is processed in open-hearth furnaces, oxygen converters and electric furnaces. If the iron alloy contains more than 2.14% carbon, then it is already cast iron.

Steel classification

On the market, 99% of all steel is a structural material in the broad sense. This group includes steels for the construction of building structures , the manufacture of machine parts, elastic elements, tools, as well as for special working conditions, having certain indicators, for example, heat-resistant, stainless and others.

The main qualities of the material are:

  • Strength, which is characterized by the ability to withstand sufficient stress.
  • Plasticity, this characteristic allows it to withstand deformation without damage to destruction both during the production of structures and at overload points during their operation.
  • Viscosity helps absorb the work of external forces and prevents the propagation of cracks.
  • Heat resistance and cold resistance.
  • Elasticity and hardness.

Steel and alloys are classified:

  • In terms of chemical and structural composition.
  • By quality. This indicator is influenced by the production method and the content of harmful impurities.
  • According to the degree of deoxidation and hardening of the metal in the mold.
  • By application.

Chemical composition

Depending on the carbon content, they are divided into groups:

  • carbon less than 0.3% C - low-carbon.
  • Medium carbon, when it is from 0.3 to 0.7% C.
  • More than 07% C is high carbon.

To improve the technological properties of the material, steel is alloyed. What does it mean? , alloying elements are added to its composition . Typically, better properties appear when alloying is complex.

In alloy steels, classification occurs due to the total percentage of impurities contained in it:

  • Low alloyed, in which less than 2.5%.
  • Medium alloyed - from 2.5% to 10%.
  • Highly alloyed - above 10%.

Structural composition

Alloy steels are divided into types according to structural analysis:

  • In annealed form - ledeburite, ferritic, hypoeutectoid, hypereutectoid, austenitic.
  • In normalized form - autenitic, martensitic, pearlitic.

The pearlite class is characterized by a low content of alloying elements. This includes alloy and carbon steels. Martensitic includes steels with a higher percentage of alloying substances. The authenite class includes materials with a high content of alloying elements.

impurities

Based on the production method and impurity content, this material is divided into 4 groups:

  1. Ordinary quality . Their chemical composition is carbonaceous. They are smelted using oxygen or in open-hearth furnaces. These steels are inexpensive and inferior in properties to other classes.
  2. High quality . According to their chemical properties, they are carbon or alloyed. Just like the previous type, they are smelted in converters or in open-hearth furnaces, while more stringent requirements for the composition of the charge, melting and casting work are observed.
  3. High quality . This type is usually smelted in electric furnaces. Very high quality steel is produced using electric furnaces with electroslag remelting. Other advanced methods are also used aimed at increasing the purity of non-metallic inclusions (sulfur and phosphorus).
  4. Thanks to electroslag remelting , which effectively removes sulfides and oxides, especially high-quality steels are created. Such steels are only alloyed. They are processed in electric furnaces, and special electrometallurgy methods are applied to them.

Steel 45

This steel alloy differs from others in a set of special characteristics that are unique to this brand. It is distinguished by its application and high functionality , unique composition of chemical compounds, and a set of foundry and other production parameters.

Analogues and substitutes

domestic analogues:

Rolled metal grade Substitute
45 40X
50
50G2
Foreign analogues of steel grade 45
USA 1044, 1045, 1045H, G10420, G10430, G10440, G10450, M1044
Germany 1.0503, 1.1191, 1.1193, C45, C45E, C45R, Cf45, Ck45, Cm45, Cq45
Japan S45C, S48C, SWRCH45K, SWRCH48K
France 1C45, 2C45, AF65, C40E, C45, C45E, C45RR, CC45, XC42H1, XC42H1TS, XC45, XC45H1, XC48, XC48H1
England 060A47, 080M, 080M46, 1449-50CS, 1449-50HS, 50HS, C45, C45E
European Union 1.1191, 2C45, C45, C45E, C45EC, C46
Italy 1C45, C43, C45, C45E, C45R, C46
Belgium C45-1, C45-2, C46
Spain C45, C45E, C45k, C48k, F.114, F.1140, F.1142
China 45, 45H, ML45, SM45, ZG310-570, ZGD345-570
Sweden 1650, 1672
Bulgaria 45, C45, C45E
Hungary A3, C45E
Poland 45
Romania OLC45, OLC45q, OLC45X
Czech 12050, 12056
Austria C45SW
Australia 1045, HK1042, K1042
Switzerland C45, Ck45
South Korea SM45C, SM48C

Alloy marking


Structural high-quality carbon steels are marked according to the standard with a two-digit number: steel 05, 08...80, 85, which indicates the average value of carbon content expressed in hundredths of a percent. Three digits of the marking indicate that the alloy contains more than 1% carbon, the letter L indicates the absence of alloying - 45l, the letter St indicates its ordinary quality - St5.

The metallurgical industry produces standard steel grades from 05kp to 60, the average carbon index of which is 0.05-0.60 percent, according to the marking. Decoding steel grade 45 (French analogue of C45) shows a content of 0.45% C.

Chemical composition (according to GOST 1050-2013)

Chemical element %
Carbon (C) 0.42-0.50
Silicon (Si) 0.17-0.37
Copper (Cu), no more 0.25
Arsenic (As), no more 0.08
Manganese (Mn) 0.50-0.80
Nickel (Ni), no more 0.25
Phosphorus (P), no more 0.035
Chromium (Cr), no more 0.25
Sulfur (S), no more 0.04

Features of steel grade 45

Steel 45 has increased characteristics of strength, endurance, is well processed, and is affordable. It has found application in almost all areas of industry, where there are constant mechanical loads and difficult temperature conditions. Products made of steel 45, for example, the extremely popular circle and hexagon st45, can withstand differences in the range from 200 to 600 o C.

If we compare some characteristics of raw materials of grade 45 and, for example, grade 35, then the influence of the proportion of carbon in the alloy composition becomes obvious. Thus, 0.42 - 0.5% versus 0.32 - 0.4% (respectively) indicates increased hardness characteristics of steel 45.

If steel 35 is classified as limitedly weldable, then steel 45 (GOST 1050-88) is very difficult to weld. This is perhaps the first of the latter’s “disadvantages”. The second is susceptibility to corrosion due to the presence of nickel and chromium.

Steel 35 is usually used for the manufacture of parts of not too high strength, subjected to light and medium loads during operation: these are axles, cylinders, crankshafts, connecting rods, while grade 45 raw materials are used to make more reliable parts with improved strength characteristics.

Comparative characteristics of raw materials can be found here:

Mechanical properties

Mechanical properties at elevated temperatures

test t, °C σ0.2, MPa σB, MPa δ5, % δ, % ψ, % KCU, J/m2
Normalization
200 340 690 10 36 64
300 255 710 22 44 66
400 225 560 21 65 55
500 175 370 23 67 39
600 78 215 33 90 59
Specimen with a diameter of 6 mm and a length of 30 mm, forged and normalized. Deformation speed 16 mm/min. Strain rate 0.009 1/s.
700 140 170 43 96
800 64 110 58 98
900 54 76 62 100
1000 34 50 72 100
1100 22 34 81 100
1200 15 27 90 100

Mechanical properties of rolled products

Heat treatment, delivery condition Section, mm σB, MPa δ5, % δ4, % ψ, %
Hot-rolled, forged, calibrated and silver steel of the 2nd category after normalization 25 600 16 40
Calibrated steel of the 5th category after hardening 640 6 30
Steel, calibrated and calibrated with a special finish after tempering or annealing <590 40
Normalized and hot rolled sheets 80 590 18
Normalized or hot rolled strips 6-25 600 16 40
Hot rolled sheet <2 550-690 14
Hot rolled sheet 2-3,9 550-690 15
Cold rolled sheet <2 550-690 15
Cold rolled sheet 2-3,9 550-690 16

Mechanical properties of forgings

Section, mm σ0.2, MPa σB, MPa δ5, % ψ, % HB
Normalization
100-300 245 470 19 42 143-179
300-500 245 470 17 35 143-179
500-800 245 470 15 30 143-179
<100 275 530 20 44 156-197
100-300 275 530 17 34 156-197
Hardening. Vacation
300-500 275 530 15 29 156-197
Normalization. Hardening. Vacation.
<100 315 570 17 39 167-207
100-300 315 570 14 34 167-207
300-500 315 570 12 29 167-207
<100 345 590 18 59 174-217
100-300 345 590 17 54 174-217
<100 395 620 17 59 187-229

Mechanical properties depending on tempering temperature

holiday t, °С σ0.2, MPa σB, MPa δ5, % ψ, % KCU, J/m2 HB
Quenching 850 °C, water. Samples with a diameter of 15 mm
450 830 980 10 40 59
500 730 830 12 45 78
550 640 780 16 50 98
600 590 730 25 55 118
Quenching 840 °C, water. Workpiece diameter 60 mm
400 520-590 730-840 12-14 46-50 50-70 202-234
500 470-520 680-770 14-16 52-58 60-90 185-210
600 410-440 610-680 18-20 61-64 90-120 168-190

Mechanical properties depending on the section

Section, mm σ0.2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
Quenching 850 °C, tempering 550 °C. Samples were cut from the center of the blanks.
15 640 780 16 50 98
30 540 730 15 45 78
75 440 690 14 40 59
100 440 690 13 40 49

Weldability and substitutes for structural and tool steels

A table is provided of the main grades of structural and tool steels, including stainless and heat-resistant, and recommendations for welding parts made from them.
STEEL GRADES

GOST Steel grades Substitutes Weldability
380-94St0welds without restrictions
St2kp St2ps St2spSt2sp St2pswelds without restrictions. for thicknesses greater than 36 mm, heating and subsequent heat treatment are recommended
St3kpSt3pswelds without restrictions. for thicknesses greater than 36 mm, heating and subsequent heat treatment are recommended
St3ps St3spSt3sp St3pswelds without restrictions. for thicknesses greater than 36 mm, heating and subsequent heat treatment are recommended
St3GpsSt3ps Steel 18Gpswelds without restrictions. for thicknesses greater than 36 mm, heating and subsequent heat treatment are recommended
St4kplimited weldability
St4psSt4splimited weldability
St5ps St5spSt6sp St4splimited welding. Preheating and subsequent heat treatment are recommended
St6pslimited welding. Preheating and subsequent heat treatment are recommended
St6spSt5splimited welding. Preheating and subsequent heat treatment are recommended
801-78ШХ15ShKh9, ShKh12, ShKh15SGwelding method KTS
SHH15SGHVG, ShH15, 9HS, HVSGwelding method KTS
ШХ4welding method KTS
1050-201308Steel 10welded without restrictions, except for parts after chemical-thermal treatment
08kp 08psSteel 08welded without restrictions, except for parts after chemical-thermal treatment
1008, 15, 08kpwelded without restrictions, except for parts after chemical-thermal treatment
10kp 10ps08kp, 15kp, 10welded without restrictions, except for parts after chemical-thermal treatment
1510, 20welded without restrictions, except for parts after chemical-thermal treatment
15kp 15ps10kp, 20kpwelds without restrictions
18kpwelds without restrictions
2015, 20welded without restrictions, except for parts after chemical-thermal treatment
20kp 20ps15kpwelded without restrictions, except for parts after chemical-thermal treatment
2520, 30welded without restrictions, except for parts after chemical-thermal treatment
3025, 35limited welding. Preheating and subsequent heat treatment are recommended
3530, 40, 35Glimited welding. Preheating and subsequent heat treatment are recommended
4035, 45, 40Glimited welding. Preheating and subsequent heat treatment are recommended
4540Х, 50, 50Г2difficult - weldable. heating and subsequent heat treatment are required
5045, 50G, 50G2, 55difficult - weldable. heating and subsequent heat treatment are required
5550, 60, 50Gnot applicable for welded structures
5830ХГТ, 20ХГНТР, 20ХН2М, 12ХНЗА, 18ХГТnot applicable for welded structures
1414-75A20Steel A12not applicable for welded structures
A30 A40GA40Gnot applicable for welded structures
1435-90U7, U7AU8not applicable for welded structures
U8, U8AU7, U7A U10, U10Anot applicable for welded structures
U9, U9AU7, U7A, U8, U8Anot applicable for welded structures
U10, U10AU10, U10Anot applicable for welded structures
4543-7115X20Xwelded without restrictions, except for parts after chemical-thermal treatment
20X15Х, 20ХН, 18ХГТwelded without restrictions, except for parts after chemical-thermal treatment
30X35Xlimited weldability
35X40Xlimited weldability
38ХА40Х, 35Хdifficult to weld
40X45Х, 35ХА, 40ХСdifficult to weld, requires heating and subsequent heat treatment
45X40Х, 45Х, 50ХНdifficult to weld, requires heating and subsequent heat treatment
50X40Х, 45Х, 50ХНdifficult to weld, requires heating and subsequent heat treatment
15G 20G20G, 20, 30Gwell weldable
30G35, 40Glimited weldability. Preheating and subsequent heat treatment are recommended
35Glimited weldability. Preheating and subsequent heat treatment are recommended
40G45, 40Хlimited weldability. Preheating and subsequent heat treatment are recommended
45G40G, 50Gdifficult to weld. Preheating and subsequent heat treatment are recommended.
50G40G, 50difficult to weld. Preheating and subsequent heat treatment are recommended.
10G209G2welds without restrictions.
35G240Xdifficult to weld. heating and subsequent heat treatment are required.
40G245G2, 60Gdifficult to weld. heating and subsequent heat treatment are required.
45G250G2difficult to weld. heating and subsequent heat treatment are required.
50G245G2, 60Gnot applicable for welded structures
47GT40HGRTnot applicable for welded structures
18ХГТ30ХГТ, 25ХГТ, 12ХН3А, 12Х2Н4А, 20ХН2М, 20ХГРwelded without restrictions, except for parts after chemical-thermal treatment
20ХГР20ХН3А, 20ХН24, 18Х1Т, 12ХН2, 12ХН3Аwelded without restrictions, except for parts after chemical-thermal treatment
25ХГТ18ХГТ, 30ХГТ, 25ХГМsubsequent heat treatment is required
30ХГТ18ХГТ, 20ХН2М, 25ХГТ, 12Х2Н4Аlimited weldability. Preheating and subsequent heat treatment are recommended
33ХСdifficult to weld
38ХС 40ХС40ХС, 38ХС, 35ХГТdifficult to weld
15HF20HFwelded without restrictions (KTS method)
40HFA40Х, 65Г, 50ХФА, 30Х3МФdifficult to weld. heating and subsequent heat treatment are required.
15ХМwelds without restrictions. Preheating and subsequent heat treatment are recommended
30ХМ 30ХМА35ХМ, 35ХРАlimited weldability. Preheating and subsequent heat treatment are recommended
35ХМ40Х, 40ХН, 30ХН, 35ХГСАlimited weldability. Preheating and subsequent heat treatment are recommended
38ХНlimited weldability. Preheating and subsequent heat treatment are recommended
20ХН15ХГ, 20ХНР, 18ХГТlimited weldability.
40ХН45ХН, 50ХН, 38ХГН, 40Х, 35ХГФ, 40ХНР, 40ХНМ, 30ХГВТdifficult to weld. Preheating and subsequent heat treatment are recommended
45ХН40ХНdifficult to weld. Preheating and subsequent heat treatment are recommended
50ХН40ХН, 60ХГnot applicable for welded structures
20ХНР20ХНlimited weldability. heating and subsequent heat treatment are required.
12ХН220ХНР, 20ХГНР, 12ХН3А, 18ХГТ, 20ХГРlimited weldability. heating and subsequent heat treatment are required.
12ХН3А12ХН2, 20ХН3А, 25ХГТ, 12Х2НР, 20ХНРlimited weldability. heating and subsequent heat treatment are required.
20ХН3А20ХГНР, 20ХНГ, 38ХА, 20ХГРlimited weldability. heating and subsequent heat treatment are required.
12Х2Н4А20ХГНР, 12ХН2, 20ХГР, 12ХН3А, 20Х2Н4Аlimited weldability. heating and subsequent heat treatment are required.
20Х2Н4А20HGNR, 20HGNTRlimited weldability. heating and subsequent heat treatment are required.
30ХН3А30Х2ГН2, 34ХН2Мlimited weldability. heating and subsequent heat treatment are required.
20ХГСА30ХГСАwelds without restrictions
25ХГСА20ХГСАwelds without restrictions
30ХГС, 30ХН2МА40HFA, 35ХМ, 40ХН, 35ХГСАlimited weldability. heating and subsequent heat treatment are required.
38Х2Н2МАnot applicable for welding work
40ХН2МА40HGT, 40HGR, 30H3MF, 45HN2MFAdifficult to weld. heating and subsequent heat treatment are required
40Х2Н2МА38Х2Н2МАdifficult to weld. heating and subsequent heat treatment are required
38ХН3МА38ХН3ВАnot applicable for welded structures
18Х2Н4МА20Х2Н4Аdifficult to weld. heating and subsequent heat treatment are required
30ХГСА40HFA, 35ХМ, 40ХН, 25ХГСА, 35ХГСАdifficult to weld. heating and subsequent heat treatment are required
35ХГСА30ХГС, 30ХГСА, 30ХГТ, 35ХМdifficult to weld. heating and subsequent heat treatment are required
30ХГСН2Аdifficult to weld. heating and subsequent heat treatment are required
38ХГН38ХГНМdifficult to weld. heating and subsequent heat treatment are required
20ХГНР20ХН3Аdifficult to weld. heating and subsequent heat treatment are required
20ХН2М20ХГР, 15ХР, 20ХНР, 20ХГНРdifficult to weld. heating and subsequent heat treatment are required
30ХН2МФА30HN2VFAdifficult to weld. heating and subsequent heat treatment are required
36Х2Н2МФАdifficult to weld.
38ХН3МФАnot applicable for welded structures
45ХН2МФАdifficult to weld. heating and subsequent heat treatment are required
20ХН4FA18Х2Н4МАnot applicable for welded structures
38Х2МУА38Х2УА, 38ХВФУ, 38Х2У, 20Х3МВФnot applicable for welded structures
5520-7916K 18Kwelds without restrictions
20Kwelds without restrictions
22Klimited weldability. Preheating and subsequent heat treatment are recommended
5632-7240Х9С2not applicable for welded structures
40Х10С2Мdifficult to weld. heating and subsequent heat treatment are required
08Х13 12Х13 20Х13 25Х13Н212Х13, 12Х18Н9Т 20Х13 12Х13, 14Х17Н2limited weldability. Heating and heat treatment are used depending on the welding method, type and purpose of structures
30Х13 40Х13not applicable for welded structures
10X14AG1612Х18Н9, 08Х18Н10, 12Х18Н9Т, 12Х18Н10Тwelds without restrictions
12Х1712Х18Н9Тnot recommended for welded structures. difficult to weld
08Х17Т, 08Х18Т112Х17, 08Х18Т1, 08Х17Тlimited weldability
95Х18not applicable for welded structures
15Х25Т12Х18Н10Тdifficult to weld. heating and subsequent heat treatment are required
15Х2815Х25Т, 20Х23Н18difficult to weld. heating and subsequent heat treatment are required
20Х23Н13limited weldability
20Х23Н1810Х25Т, 20Х23Н13limited weldability
10Х23Н10limited weldability
20Х25Н20Сlimited weldability
15Х12ВНМФdifficult to weld
20Х12ВНМФ15Х12ВНМФ, 18Х11МНФБdifficult to weld
37Х12Н8Г2МФБlimited weldability
13Х11Н2В2МФlimited weldability
45Х14Н14В2Мdifficult to weld
40X15N7G7F2MSdifficult to weld
08Х17Н13М2110Х17Н13М21well weldable
10Х17Н3М2Тwell weldable
31Х19Н9МВБТdifficult to weld
10Х14Г14Н4Т20Х13Н4Г9, 12Х18Н9Т, 12Х18Н10Т, 08Х18Н10Тwelds satisfactorily
14Х17Н220Х17Н2well weldable
12Х18Н9
17Х18Н9
20Х13Н4Г9, 10Х14Г14Н4Т, 20Х13Н4Г9welds without restrictions
08Х18Н10 08Х18Н10Т 12Х18Н9Т
12Х18Н10Т
12Х18Н10Т,
15Х25Т, 08Х18Г8Н2Т, 10Х14Г14Н4Т, 08Х17Т
welds without restrictions
12Х18Н12Т12Х18Н9, 12Х18Н9Т, 12Х18Н10Тlimited weldability
08Х18Г8Н2Т12Х18Н9welds without restrictions
20Х20Н14С2welds without restrictions
12X25N16G7ARwelds without restrictions
08Х22Н6Т12Х18Н9Т, 12Х18Н10Т, 08Х18Н10Тwelds without restrictions
06ХН28МДТAlloy: 03ХН28МДТwelds without restrictions
ХН35ВТdifficult to weld
ХН35ВТУdifficult to weld
ХН70Уlimited weldability
ХН70ВМУТdifficult to weld
KhN70VMTUFdifficult to weld
ХН77TYURdifficult to weld
ХН78ТAlloy: KhN38T, 12Kh25N16G7AR, 20Kh23N18difficult to weld
ХН80ТБУdifficult to weld
5781-8220ХГ2Цwelds without restrictions
35GS 25G2SSt5sp, St6, St5pswelds without restrictions
5950-73ХВ4ФSKS11 JIS G4404not applicable for welded structures
9Х19x2not applicable for welded structures
9ХСHVGnot applicable for welded structures
HVG9ХС, 9ХВГ, ШХ15СГnot applicable for welded structures
9ХВГHVGnot applicable for welded structures
Х6ВФХ12Ф1, Х12М, 9Х5Фnot applicable for welded structures
X12, X12VMFX12MFnot applicable for welded structures
Х12МФ
Х12Ф1
Kh6VF, Kh12F1, Kh12VMF Kh6VF, Kh6VFMnot applicable for welded structures
7ХГ2ВМФnot applicable for welded structures
7Х3 8Х38Х3 7Х3not applicable for welded structures
5ХНМ5ХНВ, 5ХГМ, 4ХМФС, 5ХНВС, 4Х5В2ФСnot applicable for welded structures
5ХГМ5ХНМ, 5ХНВ, 6ХВС, 5ХНС, 5ХНСВnot applicable for welded structures
4ZMFSnot applicable for welded structures
4Х5МФСnot applicable for welded structures
4ХМФ1Сnot applicable for welded structures
3Х3МХФnot applicable for welded structures
6ХСnot applicable for welded structures
4ХВ2С4Х5В2ФС, 4Х3В2М2not applicable for welded structures
5ХВ2СФ 6ХВ2С6ХВ2С 6ХЗФСnot applicable for welded structures
6ХВГnot applicable for welded structures
9045-9308YU11305 standard CSN411305welds without restrictions
14959-7965 7060, 70 65Gnot applicable for welded structures
7570, 80, 85not applicable for welded structures
8570, 75, 80not applicable for welded structures
60G65Gnot applicable for welded structures
65G70, U8A, 70G, 60S2A, 9HS, 50HFA, 60S2, 55S2not applicable for welded structures
55С250S2, 60S2, 35Х2AFnot applicable for welded structures
60С2 60С2А55S2, 50HFA, 60S2N2A, 60S2G, 50HFAnot applicable for welded structures
70С3А70S3A standard BDS6742not applicable for welded structures
55ХГР55ChGR standard BDS6742not applicable for welded structures
50HFA60С2А, 50ХГФА, 9ХСnot applicable for welded structures
60С2ХА60S2HFA, 60S2N2Anot applicable for welded structures
60S2HFA60С2А, 60С2ХА, 9ХС, 60С2ВАnot applicable for welded structures
65S2VA60С2А, 60С2ХАnot applicable for welded structures
60С2Н2А60С2А, 60С2ХАnot applicable for welded structures
19265-73P18P12when butt welding with steel 45 and 40X, weldability is good
R6M5K5HS6-5-2-5 standard DIN17350when butt welding with steel 45 and 40X, weldability is good
R9M4K8HS10-4-3-10 standard DIN17350when butt welding with steel 45 and 40X, weldability is good
19281-201409G209G2S, 10G2welds without restrictions
14G215HSNDlimited weldability
12GS15GSwelds without restrictions
16GS17GSwelds without restrictions
17GS16GSwelds without restrictions
17G1S17GSwelds without restrictions
09G2S10G2S, 09G2welds without restrictions
10G2S110G2S1Dwelds without restrictions
10G2BD10G2Bwelds without restrictions
15G2SFDwelds without restrictions
14G2AF16G2AFwelds without restrictions
16G2AF14G2AFwelds without restrictions
18G2FAps15G2FADps, 16G2AF, 10HSND, 15HSNDwelds without restrictions
14ХГС15HSND, 16GSwelds without restrictions
15G2AFDps16G2AF, 18G2AFps, 10HSNDwelds without restrictions
10HSND16G2AFwelds without restrictions
10KhNDP10XHAP standard PN/H84017welds without restrictions
15HSND16G2AF, 14HGS, 16GSwelds without restrictions
20072-7212MH12CrMo standard GB3077-88welds without restrictions. Preheating and subsequent heat treatment are recommended
12Х1МФ12Cr1MoV standard GB3077-88welds without restrictions. Preheating and subsequent heat treatment are recommended
25Х1МФ25Cr2MoVA standard GB3077-88welds without restrictions. Preheating and subsequent heat treatment are recommended
20Х3МВФwelds without restrictions. heating and subsequent thermal treatment are recommended
15Х5М12CrMo205 standard MSZ2295welds without restrictions. Preheating and subsequent heat treatment are recommended

If, in any case, you need to weld steel for slightly different purposes, you can use the following recommendations.
WELDABILITY OF STEEL
The main characteristics of the weldability of steels are their tendency to crack and the mechanical properties of the weld.

According to weldability, steel is divided into four groups: 1 - good weldability; 2 - satisfactory weldability; 3 - limited weldability; 4 - poor weldability

To group 1

include steels, welding of which can be performed without heating before welding and during the welding process and without subsequent heat treatment. But the use of heat treatment is not excluded to relieve internal stress. Steels St1 - St4 according to GOST 380-94 have good weldability; steel 08; 10:15; 20; 25 according to GOST 1050-2013; steel 15L; 20L according to GOST 977-88, steel 15G; 20G; 15X; 20X; 20ХГСА; 12ХН2 according to GOST 4543-71. Steel 12Х18Н9Т; 08Х18Н10; 20Х23Н18 according to GOST 5632-72

To group 2

mainly include steels, when welded under normal production conditions, cracks do not form, as well as steels that require preheating to prevent cracks, steels that must be subjected to preliminary and subsequent heat treatment. St5ps steels have satisfactory weldability. St5sp according to GOST 380-94. steel 30; 35 according to GOST 1050-2013; steel Z0L; 35L according to GOST 977-88; steel 20ХНЗА; 12Х2Н4А according to GOST 4543-71.

To group 3

include steels prone to cracking under normal welding conditions. They are pre-heated and heated. Most steels in this group are also heat treated after welding. St6ps steels have limited weldability. St6sp according to GOST 380-94; steel 40; 45; 50 according to GOST 1050-2013; steel 30ХМ; 30ХГС; ZZHS; 20Х2Н4А according to GOST 4543-71; steel 17Х18Н9; 12Х18Н9 according to GOST 5632-72.

To group 4

include steels that are most difficult to weld and prone to cracking. They must be welded with preliminary heat treatment, heating during the welding process and subsequent heat treatment. 40G steels have poor weldability; 45G; 50G; 50Х according to GOST 4543-71. steel 55L according to GOST 977-88; U7 steel; U8; U8A; U8G; U9; U10; U11; U12 according to GOST 1435-90; steel 65; 75; 85; 60G; 65G; 70G; 50ХГ; 50HGA; 55С2; 55С2А; 60С2; 60С2А according to GOST 14959-79; steel X12; XI2M; 7X3; 8X3. CHVG; ХВ4; 5ХГМ; 6ХВГ according to GOST 5950-73.

Technological properties

Forging temperature
Start 1250, end 700. Sections up to 400 mm are cooled in air.
Weldability
Difficult to weld. Welding methods: RDS and KTS. Heating and subsequent heat treatment are required.
Machinability
In the hot-rolled state at HB 170-179 and sB = 640 MPa Kutv.spl. = 1, Kub.st. = 1.
Tendency to release ability
Not inclined.
Flock sensitivity
Insensitive.

Material properties

The mechanical properties of steel 45 determine the wide distribution of this metal. The carbon concentration is 0.45%, other impurities are extremely minor. This largely determines the following characteristics:

  1. The density of steel 45 or specific gravity is 7826 kg/m 3. This ensures a low weight of the resulting products, but they cannot be called light. Density may vary slightly depending on the chemical composition.
  2. The structure is not prone to temper brittleness. Steel 45, whose characteristics can be called a universal offer, is very often subjected to hardening, due to which the surface hardness significantly increases.
  3. Very often, blanks are delivered after heat treatment. It significantly increases surface hardness. This point also determines that the hardness of steel 45 in the delivered state can vary over a fairly wide range. As a rule, the hardness is maintained at a level of 10 -1 HB, which corresponds to 170 MPa.
  4. Steel grade 45 is a difficult-to-weld metal, which makes welding difficult. That is why the structure is initially heated and only after this the elements are connected. The hardenability of steel 45 is also at a fairly low level, which complicates the cutting process. Welding can be used with a variety of welding equipment. The use of appropriate electrodes can significantly simplify the welding process. Cutting with a welding machine is also significantly more complicated.
  5. Forging is carried out quite often. It is carried out at a temperature of 1250 degrees Celsius, at the end the indicator is 700 degrees Celsius.
  6. The tensile strength and elastic modulus can vary over a fairly wide range. It all depends on the heating temperature of the surface. The yield strength of steel determines how easy it is to cast various workpieces.

Specifications

Critical point temperature

Critical point °C
Ac1 730
Ac3 755
Ar3 690
Ar1 780
Mn 350

Physical properties

T (Grad) E 10-5 (MPa) a 10 6 (1/Deg) l (W/(m deg)) r (kg/m3) C (J/(kg deg)) R 10 9 (Ohm m)
20 2 7826
100 2.01 11.9 48 7799 473
200 1.93 12.7 47 7769 494
300 1.9 13.4 44 7735 515
400 1.72 14.1 41 7698 536
500 14.6 39 7662 583
600 14.9 36 7625 578
700 15.2 31 7587 611
800 27 7595 720
900 26 708

cutting

Initial data Machinability Ku
State HB, MPa sB, MPa hard alloy high speed steel
hot rolled 170–179 650 1,0 1.0

a brief description of

Steel has a density of 7850 kg/m3. It stands out among other structural steels due to its mechanical characteristics: the yield strength is 640 MPa. Wear-resistant. Works well under conditions of variable and shock loads: endurance limit 245 MPa, impact strength 66 kJ/m2.

Grade 45 is plastic and amenable to all types of mechanical processing. Elasticity coefficient 2 MPa. The relative elongation is 15%, and the relative narrowing is 40%. The value of the coefficient of linear thermal expansion is in the range of 11.9-15.2 1/deg.

The optimal operating temperature range is 200-400 degrees. After passing this mark, the mechanical characteristics drop significantly.

Grade 45 does not have enhanced anti-corrosion properties. Without applying a protective layer, the surface of the steel becomes covered with rust. Chemically unstable to most acids and alkalis.

Steel 45 belongs to the 3rd group of weldability. The process of welding it is difficult and impossible without preparatory work: heating to 150-200 degrees. Welded seams are unstable in operation and are susceptible to cracking.

The hardness of “raw” steel is 20-22 Rockwell units. Heat treatment can increase this indicator for steels of this type by 2-2.5 times. For this, the following types are used:

  • Normalization is carried out mainly as a preliminary heat treatment. It is carried out before machining to improve the cutting process.
  • Hardening increases hardness up to 50 HRC, increases abrasive wear resistance and strength. Quenching is always done in water.
  • Low tempering is carried out in order to more evenly distribute internal stresses.

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