European Steel Names and Designations

Steel Names     (As defined in EN10027-1)

Group 1 Steels

  • S = Structural Steels
  • P = Steels for pressure purposes
  • L =mSteels for line pipework
  • E = Engineering steels
All the above are followed by the specified minimum yield stress for the smallest thickness
eg. S275  is a structural grade steel with a minimum specified yield stress of 275N/mm2

Group 2 Steels

  1. Non-Alloy steels with an average manganese content less than 1%

    2. C followed by the average percentage carbon content x 100
     
  2. Non-Alloy steels with an average manganese content greater than 1%

    3. The average percentage carbon content x 100
    The chemical symbols that characterize the steel:- Cr, Mo etc.
    The percentage content of each alloy above multiplied by a factor
     
  3. Alloy steels where at least one element exceeds 5% 

    4. The letter X
    The chemical symbols that characterize the steel:- Cr, Mo etc.
    The percentage content of each alloy above multiplied by a factor
                          Factors Used Above
Factor Alloy
4 Cr, Co, Mn, Ni, Si, W
10 Al, Be,Cu,  Mo, Nb, Pb, Ta, Ti, V, Zr
1000 B

Example 13 CrMo 4-5
0.08 to 0.18  Average x 100 = 13
CrMo = Chrome and Molybdenum are the alloys used to specify the steel.
Cr = 0.7 to 1.15  average x 4 = 4
Mo = 0.4 to 0.6 average x 10 = 5

Steel Numbers

As defined in EN10027-2, provide a numerical identification of steel composition, but not product form.  They are based on the German “Werkstoff” numbering system.

1. X X Y Y 

The number 1 denotes steel. 

The next two numbers (XX) denote the principal characteristics of the steel. Examples shown below:- 

00 Base Steel
01 General Structural Steels with Rm < 500N/mm2
03 Steels with average carbon 
C < 0.12%   Or
Rm  < 400N/mm2
04 Steels with average carbon 
C > 0.12%< 0.25%   Or
Rm > 400 < 500N/mm2
05 Steels with average carbon 
C > 0.25%< 0.55%   Or
Rm > 500 < 700N/mm2
43 Stainless Steel  Ni > 2.5%
44 Stainless Steel  Ni > 2.5%
+ Mo
48 Heat Resistant Stainless Steel Ni > 2.5%

YY Denotes sequential number assigned by the standards committee.

Example   1.4401  and  1.4404   Both materials are 316 type stainless steels, characterized by the number 44.  The last two digits suggest that whilst both steels are similar their alloy content is different, but does not define what the difference is.   1.4401 is a 316, 1.4404 is a 316L.

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