Cast Iron in Construction: A Timeless Building Material Unveiled.

Symbols of cast iron

Cast irons are alloys of iron and carbon in quantities of more than 2%. The carbon is in the form of graphite.
The European standard system for designating cast iron is based on :
A symbolic designation :
It is based on literal and numerical symbols distributed over a maximum of 6 positions.

Positions

Characters

A numerical designation :
This is complementary to the symbolic designation. It consists of nine characters.

Positions

Characters

Symbolic designation of cast iron.

The symbolic designation must begin with 2 letters (EN), followed by a dash -, the symbol GJ and the value of the minimum tensile strength in MPa.
Thus : EN-GJ L - 200
EN: Standardised cast iron
G : Casting
J : Cast iron
L : Lamellar graphite cast iron
200 : Minimum tensile strength 200 MPa

1: Graphical structure

L Lamellar
S Spheroidal
M Annealed graphite (malleable)
V Vermicular
N Example of (hard) graphite, ledeburitic.
Y Special structure, identified in the relevant product standard.

2. Microstructure or macrostructure.

A: Austenite
F: Ferrite
P: Perlite
M : Martensite
L : Ledeburite
Q : Quenched
T: Tempered and tempered
B : Black heart
W : White heart

3 Letter describing how test samples are produced

S: Sample cast separately
U: Adjacent sample
C: Sample taken from a casting.
X: Indicator of chemical components in alloy castings.

Designation of unalloyed cast iron

Two forms of designation can be adopted.
Form 1
EN - GJL - 200 S
2OO to designate the minimum tensile strength
S for characteristics measured on the separately cast sample.
Form 2
Indicator: hardness according to the type of test.
EN-GJL -HB 152 Brinell hardness
EN-GJS-HRc 35 Rockwell hardness
EN-GJN-HV 340 Vickers hardness.

Designation of alloyed cast iron

Indicators: X indicates that the cast iron is classified according to its chemical composition.
EN-GJN-X 350 Cr Ni Si 10-6-1.5
1 - X : Chemical composition
2 - 3.5% carbon (% carbon content multiplied by 100)
3 - 10% chromium (Cr)
4 - 6% nickel (Ni)
5 - 1.5% silicon (Si)

Numerical designation of cast iron

The numerical designation must begin with 2 letters EN , a dash - , the symbol JL and followed by a numerical code. It is still not widely used.
En - JL 1030
1 EN: Standardised cast iron
2 J: Cast iron
3 L: Graphical structure
4 1030: Numerical code (number to be assigned by the material standard)

Cast iron and steel grades