Steel Grade Designation System in Accordance with the European Standards
Steel Grade Designation System in accordance with the European Standards.
The European Steel Designation System is detailed in the EN 10027 standard, which consists of two parts: Part 1 defines the order in which steels are named (assigning alphanumeric designations to them), and Part 2 - the order in which steels are assigned serial numbers.
1. Steel names.
According to Part 1 of the EN 10027, steel is divided into two groups according to the order in which they are named. The first group includes steel, the names of which are determined by their purpose and mechanical or physical properties. The second group consists of steel, the names of which are determined by their chemical composition.
Group 1. The names of the steel included in the first group (see Table 1) consist of one or more letters associated with the purpose of steel, followed by digits defining its properties. Numbers can be followed by additional symbols that indicate the status of the steel supply and its purpose.
Table 1. Name of the steel of Group 1 according to EN 10027
| Initial letter | Purpose of steel, Property defined by digits |
Additional symbols | ||||
| Group 1 | Group 2 | |||||
| S = G = steel casting, put in front, if necessary | Construction steel For example: S355J0 Previously: Fe 510C Property: minimum yield strength (Re) at N/mm2 | Fracture due to impact | Temperature | С = for increased plasticity, when cold; D = for application of coating, when hot; E = for enamelling; F = for forging and stamping; L = for operation at low temperatures; M = thermomechanically hardened; N = normalized; O = for offshore structures; Q = heat-treated; S = for shipbuilding; T = for pipes; W = resistant to atmospheric corrosion | ||
| 27 JR | 40 JR | 60 JR | °C | |||
| JR | KR | LR | +20 | |||
| J0 | K0 | L0 | 0 | |||
| J2 | K2 | L2 | -20 | |||
| J3 | K3 | L3 | -30 | |||
| J4 | K4 | L4 | -40 | |||
| J5 | K5 | L5 | -50 | |||
| J6 | K6 | L6 | -60 | |||
| M = thermomechanically hardened; N = normalized; Q = after hardening and tempering; G = other properties, if necessary, defined by 1 or 2 digits | ||||||
| P = G = steel casting, put in front, if necessary |
Steel for boilers and high-pressure vessels |
M = thermomechanically hardened; N = normalized; Q = heat-treated; B = compressed gas cylinders; S = conventional pressure vessels; G = other properties, if necessary, defined by 1 or 2 digits | H = high temperature; L = low temperature; R = room temperature; X = high or low temperature | |||
| L = |
Steel for pipelines |
M = thermomechanically hardened; N = normalized; Q = heat-treated; G = other properties, if necessary, defined by 1 or 2 digits | Letter and digit, if necessary | |||
| E = |
Steel for mechanical engineering |
G = other properties, if necessary, defined by 1 or 2 digits | ||||
| B = |
Reinforcement steel |
N = normal yield; H = high yield; G = other properties, if necessary, defined by 1 or 2 digits | ||||
| Y = |
Steels for pre-stressed constructions |
C = cold-drawn wire; H = hot-rolled or pre-stressed bars; Q = heat-treated wire; S = thin cable; G = other properties, if necessary, defined by 1 or 2 digits | ||||
| R = |
Rail steel |
Mn = high manganese content; Cr = chrome-doped; G = other properties, if necessary, defined by 1 or 2 digits | Q = heat-treated wire | |||
|
H = if put before yield |
Cold-rolled flat products made of high resistance steel for cold stamping |
M = thermomechanically hardened or cold-rolled; B = hardened in the oven; P = phosphorus doped; X = two-phased; Y = with low content of embedding elements (C and N); G = other properties, if necessary, defined by 1 or 2 digits | ||||
| D = |
Flat products for cold stamping |
D = for application of coating, when hot; EK = for enameling; DK = for direct-on coating; G = other properties, if necessary, defined by 1 or 2 digits | ||||
| T = if a yield strength is set TH = if hardness is set |
Packing sheets and tapes |
No additional symbols are provided | No additional symbols are provided | |||
| M = |
Electrical steels |
For magnetic induction from 1.5 Tesla (at 50 Hz) A = non-grain-oriented; D = unalloyed, without final annealing; E = alloyed, without final annealing; N = with normal losses for remagnetization for magnetic induction from 1.7 Tesla (at 50 Hz); S = grain-oriented with limited losses for remagnetization; P = grain-oriented with low losses for remagnetization | No additional symbols are provided | |||
Review of deciphering of exampled provided in Table 3.
- S355J0 – construction steel with minimum yield strength of 355 N/mm2 impact energy at a test temperature of 0°C is at least 27 joules.
- P265B – steel for vessels with compressed gas with minimum yield strength of 265 N/mm2.
- L360QB – tempered steel for main pipelines with minimum yield strength of 360 N/mm2.
- E295 – steel for mechanical engineering with minimum yield strength of 295 N/mm2.
- B500N – reinforcement steel with yield strength of 500 N/mm2 with normal draw.
- Y1770C – cold-rolled steel wire for pre-stressed structures with minimum temporary resistance of 1770 N/mm2.
- R0880Mn – rail steel with high manganese content and minimum temporary resistance of 880 N/mm2.
- H420M – thermos-mechanically treated high-strength steel sheet for cold pressing with minimum yield strength of 420 N/mm2.
- DC12EK – cold-rolled steel sheet for cold pressing and for enamelling.
- T660 – packing sheet (tape) with specified yield strength for double reduction of 660 N/mm2.
- TH52 – packing sheet (tape) with hardness 52.
- M400-50A – electrical steel with maximum allowable losses for remagnetization 4 W/kg for magnetic induction from 1.5 Tesla at frequency 50 Hz, non-grain-oriented.
Group 2. Group 2 includes steel, the name of which is determined by the chemical composition. Group 2 is divided into four subgroups depending on the purpose and content of the alloying elements (see Table 2).
Table 2. Names of steel of Group 2 according to EN 10027
| Initial letter, | Purpose of steel Property defined by digits |
Additional symbols | ||
| Group 1 | Group 2 | |||
| С = G = steel casting, put in front, if necessary | Unalloyed steel with an average Mn content < 1% (except for free-cutting) For example: C35E previously: 2C35 First digit: average Carbon content, multiplied by 100 (up to three digits) | E = pre-set maximum Sulphur content; R = pre-set Sulphur content interval; D = for drawn wire; C = with increased plasticity, when cold; S = spring; T = instrumental; W = for welding wire; G = other properties, if necessary, with 1 or 2 digits. Letters E and R can be followed by a digit that specifies Sulphur content, multiplied by 100 | ||
| Without letter G = steel casting, put in front, if necessary | Unalloyed steel with Mn content > 1%, unalloyed free-cutting steel, alloyed steel (except high-speed) with contents of each alloying element up to 5%; For example: 28 Mn 6 Previously: 28 Mn 6 First digit: average Carbon content, multiplied by 100 (up to three digits) | Alloy elements: letters: symbols of chemical elements; Digits: separated by dash, correspond to the average content of the element, multiplied by the following coefficients | No additional symbols are provided | |
| Element | Coefficient | |||
| Cr, Co, Mn, Ni, Si, W | 4 | |||
| Al, Be, Cu, Mo, Nb, Pb, Ta, Ti, V, Zr | 10 | |||
| Ce, N, P, S | 100 | |||
| B | 1000 | |||
| X= G = steel casting, put in front, if necessary | Alloyed steel (except high-speed) with average content of at least one of the alloy elements above 5% For example: X5CrNi18-10 Previously: X 5 CrNi 18 10 First digit: average Carbon content, multiplied by 100 (up to three digits) | Alloy elements: letters: symbols of chemical elements, arranged in descending order of contained elements (in case of equal content - in alphabetical order). Digits: separated by dash, correspond to the average content of the element | ||
| HS= | High-cutting speed For example: HS2-9-1-8 Previously: HS 2-9-1-8 Digits separated by dash: content of alloy elements in the following order: W-Mo-V-Co | No additional symbols are provided | No additional symbols are provided | |
Review of the examples given in the Table, as well as additional examples.
- C35E – unalloyed steel with average Carbon content 0.35%, with content of Manganese less than 1% and with pre-set maximum content of Sulphur.
- 28Mn 6 – unalloyed steel with average Carbon content 0.28% and Manganese content 1.5% (6, divided by coefficient 4).
- 13CrMo4-5 – unalloyed steel with average content of: Carbon - 0.13%, Chrome - 1%, Molybdenum - 0.5% and content of Manganese over 1%.
- X5CrNi18-10 – alloy steel with average content of: Carbon - 0.05%, Chrome - 18.0%, Nickel - 10.0%.
2. Serial numbers.
The procedure for assigning serial numbers to steel is determined by the European Standard EN 10027 Part 2. The serial number of steel is represented as 1.XXXX, where 1. Specifies that the particular material refers to steel. Hereinafter, when expanding the accepted numbering system, it is intended to use the following digits to indicate other materials (for example, in the German material numbering system, which is the prototype of the European system, symbol 0. is used to denote cast iron, 2. – to denote heat-resistant alloys based on nickel and cobalt, 3. – to denote non-ferrous metals and alloys). Next two digits after 1. Denote the steel group number, but the last two – serial number of steel within group.
Number of the group allows unambiguously determine, what type does this or that steel belong to. Table 3 provides number intervals that are used for various types of steel. More detailed classification is available in the Standard EN 10027 Part 2.
Table 3. Numbering of steel according to EN 10027
| Steel group | Serial numbers | |
| Unalloyed steel | Steel of ordinary quality | 1.00ХХ |
| Quality steels | 1.01 ХХ - 1.09ХХ | |
| High-quality steel | 1.10ХХ - 1.13ХХ | |
| Tool unalloyed steel | 1.15ХХ - 1.18ХХ | |
| Steel alloys | Tool alloy steel | 1.20ХХ - 1.28ХХ |
| High-cutting steel | 1.32ХХ - 1.33ХХ | |
| Wear-resistant steel | 1.34ХХ | |
| Bearing steel | 1.35ХХ | |
| Materials with special properties | 1.36ХХ - 1.39ХХ | |
| Stainless steels | 1.40ХХ - 1.45ХХ | |
| Fireproof and heat-resistant steel | 1.46ХХ - 1.49ХХ | |
| High-quality alloy construction steel | 1.50ХХ - 1.85ХХ | |
| Weldable stainless steel | 1.87ХХ - 1.89ХХ |