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CAST IRON

UNI EN 16482:2014 standard specifies grades and technical characteristics of cast iron produced in continuous casting.

FLAKE IRON grades and SPHEROIDAL IRON grades
Cast iron is an iron-carbon alloy, whose carbon content exceeds 2.1%. Liquid carbon solidifies in graphite structure and depending on the shape assumed by graphite in the solidification process, cast irons are divided into two main groups:
FLAKE IRON grades and SPHEROIDAL IRON grades.

These two main groups can be divided into two sub-groups, according to the shape assumed by the iron mould (ferrite or pearlite) during the solidification : FERRITIC CAST IRON and PEARLITIC CAST IRON, both in flake iron grades and spheroidal grades.

Ferritic cast iron and Pearlitic cast iron
Ferritic cast irons have low resistance to fretting corrosion, lower hardness, higher dimensional balance in case of contact with heat, more ductility (spheroidal cast iron) and better heat dissipation. Cast irons totally ferritic are obtained by heat treatment of pearlite (complete ferritization treatment). Pearlitic cast irons have higher resistance to fretting corrosion, higher hardness and rigidity and higher mechanical properties compared to ferritic cast irons.

Flake iron grades - GJL – GJL250 GJL300
The main characteristic of this material is that graphite solidifies in lamellae shape, creating a discontinuity in the ferrous alloy composition and giving a good enhancement to the "self-lubricating" graphite effect (the seizure effect is extremely reduced) . There are very small chips during machining and lack of deformability (brittleness, no elongation before break) .

Spheroidal iron grades - GJS - GJS400 GJS500 GJS600
The main characteristic of this material is that graphite solidifies in spheroidal shape, maintaining continuity in the ferrous alloy composition. Spheroidal cast iron has higher tensile strength and a remarkable elongation compared to flake iron but the “self-lubricating" graphite effect is lower and there are many chips during machining.


FLAKE IRON

print version

CHEMICAL COMPOSITION %

CSiMnSP
2.9 - 3.65 1.8 - 2.9 0.5 - 0.7  0.1 max  0.3 max

 

MECHANICAL PROPERTIES, HARDNESS AND STRUCTURE

The chart shows expected values.
Increasing the diameter size or the cooling modulus of the bar these values decrease, as flake irons are sensitive to thickness.

Cast iron gradeDiameter or cooling modulusH.B. Hardness range 2.5/187.5UTS (N/mm2) or (Mpa) Min.-Mould structureGraphite structure
GJL-200 < 25 mm
25-50 mm
50-100 mm
100-200 mm
> 200 mm
150-210
140-200
130-190
120-190
120-190
180
155
130
115
Ring: Ferrite Core: Ferrite Ring: Type ID/IE Core: Type IA2/4 with IB/ID/IE
(20% max)
GJL-250 < 25 mm
25-50 mm
50-100 mm
100-200 mm
> 200 mm
190-250
180-230
180-220
170-220
160-220
225
195
170
155
Ring: Ferrite Core: 70% Pearlite Ring: Type ID/IE Core: Type IA3/5 with IB/ID/IE
(10% max)
GJL-300 C< 25 mm
25-50 mm
50-100 mm
100-200 mm
> 200 mm
210-260
200-240
200-230
190-230
190-230
250
235
210
170

Ring: Ferrite - Pearlite
Core: 90% Pearlite

Ring: Type ID/IE Core: Type IA3/5 with IB/ID/IE
(10% max)

 

MACHINING ALLOWANCE FOR FLAKE IRON GJL250 AND GJL300

Dimension (mm)ROUND BARS
minimum machining allowance
SQUARE and FLAT BARS
minimum machining allowance
25-50
55-75
80-100
105-150
155-200
210-280
290-350
360-430
2 mm
2 mm
2,5 mm
3 mm
4 mm
5 mm
7.5 mm
10 mm
2.5 mm
3 mm
4 mm
4 mm
5 mm
5 mm
7.5 mm
10 mm  

NOTE:
This machining allowance is referred to the radius (for round bars) or to each side (for square and flat bars).
For example: to obtain the finished size Ø 40 mm, we need minimum Ø 45 mm as raw size.
To obtain the finished size 100x100, we need minimum 108x108mm as raw size.

ALLOWANCE FOR FLAKE IRON GJL250 AND GJL300

Diameter (mm)Allowance
(compared to nominal size)
Maximum ovalization Ø-ø
20-100
105-200
> 200
-0 / + 2 mm
-0 / + 3 mm
-3 / + 3 mm
1 mm
2 mm
4 mm

 

SPHEROIDAL IRON

print version

CHEMICAL COMPOSITION %

CSiMnSP
3.4 - 3.85 2.3 - 3.1 0.1 - 0.3  0.020 max  0.1 max

 

MECHANICAL PROPERTIES, HARDNESS AND STRUCTURE

Cast iron gradeDiameter or cooling modulusH.B. Hardness range 2.5/187.5%
Pearlite
0.2 % PS (N/mm2) o
(Mpa)
-Min.-
UTS
(N/mm2) o (Mpa)
-Min.-
% EL
-Min.-

GJS 400-15 < 50 mm
> 50 mm
190 max
180 max
10 max
10 max
250
240
390
370
15
12
GJS 500-7 < 50 mm
> 50 mm
180-230 15-50 290 450
420
7
5
GJS 600-3 < 50 mm
> 50 mm
200-260 50-80 340 600
550
3
1
GJS 700-2 < 50 mm
> 50 mm
230-290 70-100 380 700
660
2
1

 

MACHINING ALLOWANCE FOR SPHEROIDAL IRON GJS400 GJS500 GJS600

Dimension (mm)ROUND BARS
minimum machining allowance
SQUARE and FLAT BARS
minimum machining allowance
25-50
55-75
80-100
105-150
155-200
210-280
290-350
360-430
2 mm
2,5 mm
3 mm
4 mm
5 mm
6 mm
8 mm
10 mm
2.5 mm
3 mm
4 mm
5 mm
6 mm
7 mm
9 mm
12 mm

NOTE:
This machining allowance is referred to the radius (for round bars) or to each side (for square and flat bars).
For example: to obtain the finished size Ø 40 mm, we need minimum Ø 45 mm as raw size.
To obtain the finished size 100x100, we need minimum 108x108mm as raw size.

ALLOWANCE FOR SPHEROIDAL IRON GJS400 GJS500 GJS600

Ovalization of the bar included:

Diameter (mm)Allowance
(compared to nominal size)
Maximum ovalization Ø-ø
20-100
105-200
> 200
-0 / + 2 mm
-0 / + 3 mm
-3 / + 3 mm
1 mm
2 mm
4 mm