| Element | % Min | % Max |  The Iron-Carbon diaphragm |
| C (Carbon) | 2,9 | 3,65 | |
| Si (Silice) | 1,8 | 2,9 | |
| Mn (Manganese) | 0,4 | 0,7 | |
| S (Sulphur) | 0 | 0,10 | |
| P (Phosphorus) | 0 | 0,30 | |
| Others | Traces | ||
| Fe (Iron) | Residual at 100% | ||
| NB: Data may differ according to the various foundries | |||
| Cast Iron (common name) |
Hardness HB (30) |
Tensile Strength Rm N/mm2 |
Yield load Rp 0,2 |
Elong. A% |
Structure | Graphite |
| GJL150 (G15) | 140-190 | 150 | – | 1-3 | Ferrite | Lamellar |
| GJL200 (G20) | 150-210 | 200 | – | 1-3 | Ferrite-pearlite | Lamellar |
| GJL250 (G25) | 170-240 | 250 | – | 1-3 | Pearlite | Lamellar |
| GJL300 (G30) | 190-240 | 300 | – | 1-3 | Pearlite | Lamellar |
| GJS400 (GS400) | 140-200 | 400 | 240 | 8-18 | Ferrite | Spheroidal |
The above details are provided as plain examples as they can only be measured on standard test pieces cast in auto mode on a die-cast system. The actual values for any specific cast strongly depend on the thickness of the element in question and the morphology of the cast (in fact these two aspects join force to determine the cooling curves and therefore the mechanical properties as a whole).
Below is an example showing how the tensile strength varies in relation to the different thicknesses.
GREY IRON CASTS UNI EN 1561
| Designation of materials |
Wall thickness Determinating [mm] |
Required Rm tensile resistance (On sample) [N/mm2] |
Required tensile resistance Rm (On sample) [N/mm2] |
Foreseen Rm tensile resistance (On sample) [N/mm2] |
| EN-GJL-150 | 5 10 20 40 80 |
from 150 to 250 | – – 120 110 100 |
155 130 110 95 80 |
| EN-GJL-200 | 5 10 20 40 80 |
from 200 to 300 | – – 170 150 140 |
205 180 155 130 115 |
| EN-GJL-250 | 5 10 20 40 80 |
from 250 to 350 | – – 210 190 170 |
250 225 195 170 155 |
| EN-GJL-300 | 10 20 40 80 |
from 250 to 350 | – 250 220 210 |
270 240 210 195 |
Grey iron microstructure Propagation of cracks inside grey iron. The crack forms in the graphite (present in the form of laminar) and then propagates. |
Spheroidal iron microstructure Propagation of cracks inside the spheroidal iron. The crack forms in the graphite (present in the form of spheroids) and then propagates. |
SPHEROIDAL IRON CASTS UNI EN 1563
| Type of iron |
Tensile resistance |
Unit load of deviance of proportionality 0,2% |
Elongation |
Brinell Hardness |
| Designation of the material |
Rm [N/mm2] min |
Rp0,2 [N/mm2] min |
A% min | HB |
| EN-GJS-400-18 |
400 | 250 | 18 | from 130 to 175 |
| EN-GJS-400-15 | 400 | 250 | 15 | from 135 to 180 |
| EN-GJS-450-10 | 450 | 310 | 10 | from 160 to 210 |
| EN-GJS-500-7 | 500 | 320 | 7 | from 170 to 230 |
| EN-GJS-600-3 | 600 | 370 | 3 | from 190 to 270 |