The document discusses various steel grading systems used internationally such as AISI, SAE, BS EN, JIS, and ASTM. It provides details on the naming conventions and systems used to designate steel grades based on their intended end use, mechanical properties, chemical composition, and more. BS EN 10027-1 and 10027-2 standards are described in depth for designating structural, alloy, tool, and stainless steels based on factors like carbon content, alloying elements, yield strength, and assigned number systems. Common end uses of certain grades are also briefly mentioned.

1. NAMING CONVENTIONS OF
STEEL
AIM: TO HELP GUESS THE END USE FROM GRADES

2. AVAILABLE GRADING SYSTEMS
• SAE steel grades
• British Standards
• International Organization for
Standardization ISO/TS 4949:2003 For Steel only
• European standards - EN 10027
• Japanese steel grades : JIS standard
• Germany steel grades : DIN standard
• China steel grades : GB standard
• Unified Numbering System (UNS) of ASTM Int. For alloys in
general
• The Society of Automotive Engineers (SAE).

3. FOR INDIAN STEEL INDUSTRY
American Standards : AISI & SAE series
British Standards : EN & RVSS series
German Standards : DIN series
Japanese Standards : JIS series
Indian Standards : IS series
Indian Railways : RDSO series
French Standards : AFNOR series
State Road Transport
: ASTRU series
Standards

4. BS EN STANDARDS USED
• BS EN 10079:1992 : It is a Reference standard which
defines steel products based on their physical
properties
a) Their shape and dimensions
b) Their appearance and surface condition
• BS EN 10027-1:1992:The steel grade names consist
of alpha numerical characters and define two main
designation systems.

5. STEELS DESIGNATION (BS EN 10027-1:1992) ON THE
BASIS OF THEIR USE AND THEIR MECHANICAL
PROPERTIES.
Letter Application Mechanical Property that is indicated
S Structural Steel Minimum Yield Strength
P Pressure Purposes Minimum Yield Strength
L Line Pipe Minimum Yield Strength
E Engineering Minimum Yield Strength
B Reinforcing Steel Characteristic Yield Case
Y Pre-stressing Steel Minimum Yield Case
R Rails Minimum Yield Case
H High Strength Cold Rolled Minimum Yield Case
D Flat Products for Cold Forming C, D or X followed by two numbers characterising steel
T Tinmill Products Nominal Yield Case
100 x specific loss in W/kg, "—"
M Electrical Steel 100 x nom thick in mm
Letter for type of steel (A,B,E,N,S or P)
Eg. S420 designates a structural steel(S) with a specified yield strength of 420MPa

6. BS EN 10027-1:1992 STEELS DESIGNATION ON THE
BASIS OF THEIR CHEMICAL COMPOSITION
Carbon Steel : According to AISI (American Iron and Steel
Institute) , a steel can be called carbon steel when no minimum
percentage of other alloying elements is mandatory for
obtaining the desired properties. And the percentage
composition {by weight } does not exceed –
• 1.65 for Mn
• 0.6 for Si
• 0.6 for Cu
BS EN 10027-1:1992 designation : The grade name is „C‟
followed by a number „XX‟ where XX is ( PC of carbon* 100)
Eg: a “C56” steel is essentially a carbon steel with 0.56 weight
percentage of carbon

7. BS EN 10027-1:1992 STEELS DESIGNATION ON THE
BASIS OF THEIR CHEMICAL COMPOSITION
Alloy Steel: Steel that does not fall under Carbon steel
criteria and have significant proportions of alloying
elements.
BS EN 10027-1:1992 designation : The name consists of
X followed by (100 x Carbon %age ) then the Symbols
of alloying elements followed by numbers indicating
the associated % contents.
Eg : a “X2CrNi18-9” steel is an alloy steel with average Carbon,
Chromium and Nikel percentages of 0.2%, 18 %, 9% respectively.

8. BS EN 10027-2:1992
• This system gives a steel number to the grade
• Grade number consists of 1 (denoting steel)
followed by a point and then 4 figures.
Steel Number= 1.YYXX
• YY (2 digit number) represent the steel type
• XX (2 digit number) does not represent anything
• XX is awarded sequentially by a European Registering Office.

9. BS EN 10027-2:1992
Carbon Steel :
1.00XX & 1.90XX ..Base Steels
1.01XX& 1.91XX ..Quality Steel , General structural steels
1.02XX& 1.92XX ..Structural Steels (Not intended for heat treatment )
1.03XX& 1.93XX ..Steels with average C< 0,12%
1.93XX..Steels with average C< 0,12%
1.04XX& 1.94XX ..Steels with average C >= 0,12% < 0,25%
1.05XX & 1.95XX..Steels with average C >= 0,25% < 0,55%
1.06XX& 1.96XX ..Steels with average C > 0,55%
1.07XX & 1.97XX..Steels with higher P or S content

10. BS EN 10027-2:1992
Special Carbon Steel:
1.10XX & 1.90XX .. Steels with special physical properties
1.11XX .. Structural, Pressure vessel and engineering
steels with C < 0,5%
1.12XX & 1.90XX .. Structural Pressure vessel and engineering
steels with C ≥ 0,5% )
1.13XX .. Structural Pressure vessel and engineering
steels with special requirements
1.14XX .. Special steels for specific purpose
1.15XX to 1.18XX .. Tool steels
1.19XX .. Special steels

11. BS EN 10027-2:1992
Alloy Steel :
1.08XX & 1.98XX ..Steels with special physical properties
1.09XX & 1.99XX ..Steels for other applications
1.2000 -1.2999 ..Tool Steels
1.20XX..Tool Steels-Cr
1.21XX..Tool Steels-(Cr-Si , Cr-Mn ,Cr-Mn-Si,
1.22XX..Tool Steels-(Cr-V , Cr-V_Si ,Cr-V-Mn,Cr-V-Mn_Si
1.23XX..Tool Steels .. (Cr-Mo, Cr-Mo-V, Mo-V )
1.24XX..Tool Steels .. (W, Cr-W)
1.25XX..Tool Steels .. (W-V, Cr-W-V)
1.26XX..Tool Steels .. (other W)
1.27XX..Tool Steels .. (with Ni)
1.28XX..Other Tool Steels )
1.29XX..Other Tool Steels ]

12. BS EN 10027-2:1992
Alloy Steel :
1.3000 - 1.3999.. Special Steels
1.35XX .. Bearing Steels
1.39XX .. Ni Steels with special physical properties
1.4000 -1.4999 .. Stainless and Heat Resisting
1.43XX .. Stainless Steels ( > 2.5% Ni but without Mo & Ti)
1.44XX .. Stainless steel ( < 2,5% Ni and Mo, but without
Nb and Ti)
1.5000 -1.8999 .. Structural, pressure vessel and engineering steels
1.51XX .. Structural , Pressure Vessel , Engineering Steels .
(with Mn-Si, Mn-Cr)
1.61XX ..Special steels, structural, Pressure Vessel and
Engineering steels
1.70XX..Cr, Cr-B
And so on. . . !!!

13. SAE DESIGNATIONS FOR CARBON
STEEL AND ALLOY STEEL
• The name consists in 4 digits
• The first digit denotes main alloying element/elements
SAE designation Type
1xxx Carbon steels
2xxx Nickel steels
3xxx Nickel-chromium steels
4xxx Molybdenum steels
5xxx Chromium steels
6xxx Chromium-vanadium steels
7xxx Tungsten steels
8xxx Nickel-chromium-vanadium steels
9xxx Silicon-manganese steels

14. SAE DESIGNATIONS FOR CARBON
STEEL AND ALLOY STEEL
• Second digit represents secondary alloying elements
• The last two digits indicate the carbon content in hundredth of
a percent.
SAE designation Type
10xx Plain carbon (Mn 1.00% max)
Eg. “1049 steel” is a
plain carbon steel with 11xx Resulfurized carbon steel
0.49% carbon
12xx Resulfurized and rephosphorized
15xx Plain carbon (Mn 1.00% to 1.65%)
Tools and machine xxBxx Boron steels
manufacturing wear plates
blades fans etc xxLxx Leaded steels
ductile

15. END USES OF SAE GRADES
(SUPERFICIAL IDEA)
Plain carbon used in
noncritical structural
Cylinders, turbine
fabrications
blades, bolts
High carbon steel used for
forged products ,
making tools
bearings(high
stress conditions)
Spring , bolts
Fabrications for
underground
usage(high corrosion
High temp and high
environment)
corrosion condition
(boilers pipes furnaces)
Cutting and
Drilling tools

16. STAINLESS STEEL GRADES
Usual representation : A three digit number sometimes followed by
a letter.
Series 400 (martensitic) eg. 410 440C
used in : Fasteners, pump shafts
Series 400 (ferritic) eg. 405 436S
used in : automotive exhaust systems, catalytic converters, radiator
caps, and chimney liners
200/300 Series (austenitic) eg. 304
used in : Food equipment, chemical equipment, architectural
applications
Suffixes A,B,C are used to indicate carbon content
„A‟ type will mainly be required where aesthetics is needed as it is
More stain resistant. C type is the hardest and used to make stainless
steel tools and springs.

17. A TYPICAL ASTM DESIGNATION
ASTM A 582/A582M-95b (2000),
Grade 303Se
A
Indicates sequential
ferrous number
material Year of
last
revision
Indicates Year of
that the last re- Usually
standard approval written in
was SAE
written in standard
SI units notation

18. SYMBOLS IN EUROPEAN STANDARDS
Code Condition
A Annealed
QT Quenched and tempered
Process Codes N Normalised
SR Stress relieved
C Cold worked
U Untreated
Application
Meaning
symbol
S Structural steel
P Steel for pressure lines and vessels
L Steel for pipe and tube
Applications Codes
E Engineering steels
B Steel for reinforced concrete
R Steel for rail use

19. JIS AND BS STANDARDS
"JIS X 0208:1997" • X will be G for ferrous alloys
and H for non-ferrous
• Stainless steels ae named according to AISI
conventions (SUS 304)
• SUH -> Heat resistant alloys
A letter that denotes
the
• SCS and SCH numbers are used for stainless
area of application steel castings.
of material
“BS XXXX[-P]:YYYY”
Number of the year
standard
Sub-division number
in the standard