Steel grades

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

European standard steel grades[edit]

EN 10027-1 steel grade designation system.

[1] European standard steel grade names fall into two categories:

  1. Steel specified by purpose of use and mechanical properties.
  2. 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[edit]

Basic steel 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.

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 Strength Cold Rolled Minimum Yield Case
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 x specific loss in W/kg

Number = 100 x nom thick in mm Letter for type of steel (A,B,E,N,S or P)

Additional symbols[edit]

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
Impact
code
Testing
strength
Temperature
code
Testing
temperature
J 27 J R Room temperature
K 40 J O 0°C
L 60 J 2 -20°C
3 -30°C
4 -40°C
5 -50°C
6 -60°C

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 Untreated

European standard steel number[edit]

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.

Comparison[edit]

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

Comparison of steel grades by chemistry[2][3]
EN steel number EN steel name SAE grade UNS DIN BS 970 UNI JIS
Carbon steels
1.1141
1.0401
1.0453
C15D
C18D
1010
1018
CK15
C15
C16.8
040A15
080M15
080A15
EN3B
C15
C16
1C15
S12C
S15
S15CK
S15C
1.0503
1.1191
1.1193
1.1194
C45 1045 C45
CK45
CF45
CQ45
060A47
080A46
080M46
C45
1C45
C46
C43
S45C
S48C
1.0726
1.0727
35S20
45S20
1140/1146 35S20
45S20
212M40
En8M
1.0715
1.0736
11SMn37 1215 9SMn28
9SMn36
230M07
En1A
CF9SMn28
CF9SMn36
SUM 25
SUM 22
1.0718
1.0737
11SMnPb30
11SMnPb37
12L14 9SMnPb28
9SMnPb36
230M07 Leaded
En1B Leaded
CF9SMnPb29
CF9SMnPb36
SUM 22
SUM 23
SUM 24
Alloy steels
1.7218 4130 25CrMo4
GS-25CrMo4
708A30
CDS110
25CrMo4 (KB)
30CrMo4
SCM 420
SCM 430
SCCrM1
1.7223
1.7225
1.7227
1.3563
42CrMo4 4140/4142 41CrMo4
42CrMo4
42CrMoS4
43CrMo4
708M40
708A42
709M40
En19
En19C
41CrMo4
38CrMo4 (KB)
G40 CrMo4
42CrMo4
SCM 440
SCM 440H
SNB 7
SCM 4M
SCM 4
1.6582
1.6562
34CrNiMo6 4340 34CrNiMo6
40NiCrMo8-4
817M40
En24
35NiCrMo6 (KB)
40NiCrMo7 (KB)
SNCM 447
SNB24-1-5
1.6543
1.6523
20NiCrMo2-2 8620 21NiCrMo22
21NiCrMo2
805A20
805M20
20NiCrMo2 SNCM 200 (H)
Stainless steels
1.4310 X10CrNi18-8 301 S30100
1.4318 X2CrNiN18-7 301LN
1.4305 X8CrNiS18-9 303 S30300 X10CrNiS18-9 303S 31
En58M
X10CrNiS18-09 SUS 303
1.4301 X2CrNi19-11
X2CrNi18-10
304 S30400 X5CrNi18-9
X5CrNi18-10
XCrNi19-9
304S 15
304S 16
304S 18
304S 25
En58E
X5CrNi18-10 SUS 304
SUS 304-CSP
1.4306 X2CrNi19-11 304L S30403 304S 11 SUS304L
1.4311 X2CrNiN18-10 304LN S30453
1.4948[citation needed] X6CrNi18-11 304H S30409
1.4303[citation needed] X5CrNi18-12 305 S30500
1.4401
1.4436
X5CrNiMo17-12-2
X5CrNiMo18-14-3
316 S31600 X5CrNiMo17 12 2
X5CrNiMo17 13 3
X5CrNiMo 19 11
X5CrNiMo 18 11
316S 29
316S 31
316S 33
En58J
X5CrNiMo17 12
X5CrNiMo17 13
X8CrNiMo17 13
SUS 316
SUS316TP
1.4404 X2CrNiMo17-12-2 316L S31603 316S 11 SUS316L
1.4406
1.4429
X2CrNiMoN17-12-2
X2CrNiMoN17-13-3
316LN S31653
1.4571 316Ti S31635 X6CrNiMoTi17-12 320S 33
1.4438 X2CrNiMo18-15-4 317L S31703
1.4541 321 S32100 X6CrNiTi18-10 321S 31 SUS321
1.4878[citation needed] X12CrNiTi18-9 321H S32109
1.4512[citation needed] X6CrTi12 409 S40900
410 S41000
1.4016 430 S43000 X6Cr17 430S 17 SUS430
440A S44002
1.4112[citation needed] 440B S44003
1.4125[citation needed] 440C S44004 X105CrMo17 SUS440C
1.4104 430F S44020 X14CrMoS17 SUS430F
1.4539 X1NiCrMoCu25-20-5 904L N08904
1.4547 X1CrNiMoCuN20-18-7 S31254
Tool steels
1.2363 X100CrMoV5 A-2 T30102[4] X100CrMoV51 BA 2 X100CrMoV5-1 KU SKD 12
A-3 T30103[5]
A-4 T30104[6]
A-6 T30106[7]
A-7 T30107[8]
A-8 T30108[9]
A-9 T30109[10]
1.2379 X153CrMoV12 D-2 X153CrMoV12-1 BD 2 X155CrVMo12-1 SKD 11
1.2510 O-1 100MnCrW4 Bo 1 95MnWCr-5 KU

References[edit]

Notes[edit]

  1. ^ EN 10027, European committee for standardisation 
  2. ^ "Standards comparison". Retrieved 2008-12-31. .
  3. ^ Oberg, pp. 411-412.
  4. ^ AISI A2, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  5. ^ AISI A3, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  6. ^ AISI A4, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  7. ^ AISI A6, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  8. ^ AISI A7, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  9. ^ AISI A8, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 
  10. ^ AISI A9, Efunda, archived from the original on 2010-12-25, retrieved 2010-12-25. 

Bibliography[edit]

  • Oberg, E.; et al. (1996), Machinery's Handbook (25th ed.), Industrial Press Inc 

External links[edit]