Steel grades

Steel grades are grades used to classify various steels by their composition and physical properties. Steel grades have been developed by a number of standards organizations.

Steel grades standards by country For alloys in general (including steel), unified numbering system (UNS) of ASTM International and the Society of Automotive Engineers (SAE). American steel grades : AISI/SAE steel grades standard British Standards International Organization for Standardization ISO/TS 4949:2016 European standards – EN 10027 Japanese steel grades : Japanese Industrial Standards (JIS) standard and NK standard Germany steel grades : DIN standard China steel grades : GB standard Czech steel grades : ČSN standard Russia steel grades : GOST standard Spain steel grades : UNE standard France steel grades : AFNOR standard Italy steel grades : UNI standard Sweden steel grades : SIS standard Norway steel grades : DNV standard

Note that an increasing number of national European standards (DIN, AFNOR, UNE, UNI, etc.) and UK standards are being withdrawn and replaced by European Standards (EN). This task is carried out by the Comité Européen de Normalisation (CEN) (European Committee for Standardization).

European standard steel grades

European standard steel grade names fall into two categories: Steel specified by purpose of use and mechanical properties. Steel specified by chemical composition.

The inclusion of a letter 'G' before the code indicates the steel is specified in the form of a casting.

Category 1: Steel specified by purpose of use and mechanical properties Basic grade designations for category 1 steels consist of a single letter (designating application) then a number signifying the mechanical property (often yield strength) dictated in the standard for that application designation. For some application designations another letter is included before the property value, this number is used to indicate any special requirements or conditions. These additional letters and values depend entirely on the application of the steel and are specified in the standard and far too numerous to mention here.

The next set of 3 digits gives the steel's minimum yield strength. So S355 has a minimum yield strength of 355 MPa for the smallest thickness range covered by the relevant standard – i.e. EN10025.

Below is a table indicating the most common application codes.

Application symbol Meaning Mechanical Property Details S Structural steel Minimum Yield Strength P Steel for pressure lines and vessels Minimum Yield Strength L Steel for pipe and tube Minimum Yield Strength E Engineering steels Minimum Yield Strength B Steel for reinforced concrete Characteristic Yield Case R Steel for rail use Minimum Yield Case H High Tensile Strength Flat products Minimum Yield Case If followed by T then the given mechanical property is minimum tensile strength D Flat Products for Cold Forming Followed by C, D or X and two numbers characterising steel T Tinmill Products Nominal Yield Case M Electrical Steel Number = 100 × specific loss in W/kg Number = 100 × nom thick in mm

Letter for type of product (A, K, P or S)

Additional symbols In addition to the above category codes there are symbols that can be added to the grade code to identify any additional compositional requirements, delivery conditions, mechanical properties, &c. These values depend solely on the type/application code given in the first part of the code and are so numerous as to be impossible to indicate here. Additional symbols are separated from the main code by the plus sign (+).

The most common additional symbols are the impact and temperature codes for structural steels, category 1 - Sxxx.

Impact Resistance Temperature Impactcode Testingstrength Temperaturecode Testingtemperature J 27 J R Room temperature K 40 J 0 0 °C L 60 J 2 -20 °C 3 -30 °C 4 -40 °C 5 -50 °C 6 -60 °C

Example : S355J2

Delivery condition codes are also relatively common, the most common being:

Code Condition A Annealed QT Quenched and tempered N Normalised SR Stress relieved C Cold worked U UntreatedGDeoxidated Example : S355J2+N

Electrical steel Electrical steel type of product letters (bold are most recent version 2016): CodeMaximum specific loss expressed for magnetic inductionType of productA1.5 T @50 Hznon orientedD (formerly B)"non-alloy semi-finished (not finally annealed)E"alloy semi-finished (not finally annealed)K (=D+E)"non-alloy and alloy electrical steel sheet/strip in the semi-processed stateN"for normal grain oriented productsP1.7 T @50 Hzhigh permeability grain orientedS"conventional grain oriented

Standard per steel name According to EN 10027-1 +ApplicationMechanical propertyadditional symbolStandardS235JREN 10025-2355JREN 10025-2J0EN 10025-2J2EN 10025-2K2EN 10025-2NEN 10025-3NLEN 10025-3450J0EN 10025-2P265GHEN 10028-2NBEN 10120355NHEN 10028-3MEN 10028-5ML1EN 10028-5QEN 10028-6

Category 2: Steel specified by chemical composition In addition to the descriptive steel grade naming system indicated above, within EN 10027-2 is defined a system for creating unique steel grade numbers. While less descriptive and intuitive than the grand names they are easier to tabulate and use in data processing applications.

The number is in the following format: x.yyzz(zz)Where x is the material type (only 1 is specified so far), yy is the steel group number (specified in EN10027-2) and zz(zz) is a sequential number designated by the certifying body, the number in brackets being unused but reserved for later use.

The steel groups are indicated below:

Code Type Non-alloy steels 00 & 90 Basic steels 0x & 9x Quality steels 1x Special steels Alloy steels 2x Tool steels 3x Miscellaneous steels 4x Stainless and heat resistant steels 5x – 8x Structural, pressure vessel and engineering steels 08 & 98 Special physical properties 09 & 99 Other purpose steels

The current certification body is the VDEh in Düsseldorf, Germany.

Comparisons

Below is a table comparing steel grades from different grading systems.

+Comparison of steel grades by chemistry.Oberg, pp. 411-412. EN steel number(Europe) EN steel name(Europe) ASTM grade(USA) AISI/SAE grade(USA) UNS(USA) DIN(Germany) BS(UK) UNI(Italy) JIS(Japan) Carbon steels 1.11411.04011.0453 C15DC18D 10101018 CK15C15C16.8 040A15080M15080A15EN3B C15C161C15 S12CS15S15CKS15C 1.05031.11911.11931.1194 C45 1045 C45CK45CF45CQ45 060A47080A46080M46 C451C45C46C43 S45CS48C 1.07261.0727 35S2045S20 1140/1146 35S2045S20 212M40En8M 1.07151.0736 11SMn37 1215 9SMn289SMn36 230M07En1A CF9SMn28CF9SMn36 SUM 25SUM 22 1.07181.0737 11SMnPb3011SMnPb37 12L14 9SMnPb289SMnPb36 230M07 LeadedEn1B Leaded CF9SMnPb29CF9SMnPb36 SUM 22SUM 23SUM 24 1.1555 C120U C125W BW1C C120KU SK2 Alloy steels 1.7218 4130 25CrMo4GS-25CrMo4 708A30CDS110 25CrMo4 (KB)30CrMo4 SCM 420SCM 430SCCrM1 1.72231.72251.72271.3563 42CrMo4 4140/4142 41CrMo442CrMo442CrMoS443CrMo4 708M40708A42709M40En19En19C 41CrMo438CrMo4 (KB)G40 CrMo442CrMo4 SCM 440SCM 440HSNB 7 SCM 4MSCM 4 1.65821.6562 34CrNiMo6 4340 34CrNiMo640NiCrMo8-4 817M40En24 35NiCrMo6 (KB)40NiCrMo7 (KB) SNCM 447SNB24-1-5 1.65431.6523 20NiCrMo2-2 8620 21NiCrMo2221NiCrMo2 805A20805M20 20NiCrMo2 SNCM 200 (H) 1.5415 16Mo3 A204 A/B/C K12822K12320K12020K11820 15Mo3 1503-243B240243 15Mo316Mo3 STBA12 Stainless steels 1.4310 X10CrNi18-8 301 S30100 1.4318 X2CrNiN18-7 301LN 1.4305 X8CrNiS18-9 303 S30300 X10CrNiS18-9 303S 31En58M X10CrNiS18-09 SUS 303 1.4301 X2CrNi19-11X2CrNi18-10 304 S30400 X5CrNi18-9X5CrNi18-10XCrNi19-9 304S 15304S 16304S 18304S 25En58E X5CrNi18-10 SUS 304SUS 304-CSP 1.4306 X2CrNi19-11 304L S30403 304S 11 SUS304L 1.4311 X2CrNiN18-10 304LN S30453 1.4948 X6CrNi18-11 304H S30409 1.4303 X5CrNi18-12 305 S30500 1.44011.4436 X5CrNiMo17-12-2X5CrNiMo18-14-3 316 S31600 X5CrNiMo17 12 2X5CrNiMo17 13 3X5CrNiMo 19 11X5CrNiMo 18 11 316S 29316S 31316S 33En58J X5CrNiMo17 12X5CrNiMo17 13X8CrNiMo17 13 SUS 316SUS316TP 1.4404 X2CrNiMo17-12-2 316L S31603 316S 11 SUS316L 1.44061.4429 X2CrNiMoN17-12-2X2CrNiMoN17-13-3 316LN S31653 1.4462X2CrNiMoN22.5.3S31803 S32205X2CrNiMoN22.5.3 1.4571 316Ti S31635 X6CrNiMoTi17-12 320S 33 1.4438 X2CrNiMo18-15-4 317L S31703 1.4541 321 S32100 X6CrNiTi18-10 321S 31 SUS321 1.4848 GX40CrNiSi25-20 A351 HK40 J94204 SEW 595 GX40CrNiSi25-20 310C40 SCH22 1.4859 GX10NiCrSiNb32-20 N08151 GX10NiCrSiNb32-20 1.4878 X12CrNiTi18-9 X8CrNiTi18-10 321H S32109 1.4906 X7CrNiNb18-10 347H S34709 1.4512 X6CrTi12 409 S40900 SUH409 410 S41000 1.4016 430 S43000 X6Cr17 430S 17 SUS430 440A S44002 1.4112 440B S44003 1.4125 440C S44004 X105CrMo17 SUS440C 1.4104 430F S44020 X14CrMoS17 SUS430F1.4057 X17CrNi16-2 431 XS43100 X16CrNi16431S 29SUS4311.542316Mo5A335 P1 45204419H4419 K1152216Mo5 STPA121.771514MoV6-3A335 P2 K11547 14MoV6-3 660 STPA201.73351.733813CrMo4-510CrMo5-5A335 P11 K11597 STPA231.73751.73801.738310CrMo9-1011CrMo9-1012CrMo9-10A335 P22 K21590 17175 10CrMo910 STPA241.73621.7366X11CrMo5X12CrMo512CrMo19-5A335 P5 501502 K41545S50100S50200 STPA251.7386X11CrMo9-1X12CrMo9-1A335 P9 503 S50400S50488K90941 STPA26 1.4903 X10CrMoVNbN9-1A335 P91 K91560 X10CrMoVNbN9-1 1.49051.4906 X11CrMoWVNb9-1-1X12CrMoWVNbN10-1-1A335 P92 K92460 X11CrMoWVNb9-1-1X12CrMoWVNbN10-1-1 1.4539 X1NiCrMoCu25-20-5 904L N08904 1.4547 X1CrNiMoCuN20-18-7 S31254 1.4565NIT50S20910NIT60S21800 Tool steels 1.2363 X100CrMoV5 A-2 T30102 X100CrMoV51 BA 2 X100CrMoV5-1 KU SKD 12 A-3 T30103 A-4 T30104 A-6 T30106 A-7 T30107 A-8 T30108 A-9 T30109 1.2365 X32CrMoV3-332CrMoV12-28 H10 T20810 X32CrMoV3-332CrMoV12-28 SKD 7 1.2379 X153CrMoV12 D-2 X153CrMoV12-1 BD 2 X155CrVMo12-1 SKD 11 1.2510 O-1 100MnCrW4 Bo 1 95MnWCr-5 KU

American Petroleum Institute (API) steel grades The American Petroleum Institute has a standardized steel grading system for various properties of steel composites.

Color coding In order to clearly distinguish the steel grade, tubing, casing and its coupling should be painted with color codes respectively. Color bands should be painted on tubing and casing body longer than 600mm to either end. The whole outer-body of the coupling needs to be painted color and then color codes. Steel GradeCouplingTubular BodyAPI Tubing and CasingH40NoneNone or black band at the manufacturer's optionJ55all green.one green bandK55all greentwo green bandsN80-1 all redone red bandN80-Q all red + one green bandone red band + one green bandL80-1all red + one brown bandone red band + one brown bandL80-9Crcolorless + two yellow bandsone red band + one brown band + two yellow bandsL80-13Crcolorless + one yellow bandone red band + one brown band + one yellow bandC90-1all purpleone purple bandT95-1all silverone silver bandC110all white + two brown bandsone white band + two brown bandsP110all whiteone white bandQ125all orangeone orange band API 5B and 5CT provide various steel grades and color codes of each grade, with general information of casing and tubing.

References

Notes

Bibliography

External links Steel classification according to EN 10027-2.Free searchable database "European steel and alloy grades" Comparison of various steel standards Comparison of various tool steel standards General guide to the EN 10027 steel name and numbering systems.