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Iron Alloys
Iron alloys
Sperre Støperi AS casts all standard material qualities in grey cast iron and ductile iron. Cast iron is an iron alloy with more than 2 % carbon. In its hardened state, the carbon is in the form of free graphite flakes in the metal structure. This means that a fracture can easily spread along the graphite flakes, which have no mechanical strength. Grey cast iron is the material that most people associate with cast iron. Grey cast iron is a material that people have used for several centuries. Grey cast iron is a relatively brittle material (it does not stretch). The surface of fracture is grey - giving the metal its name. However, the material has a number of other useful qualities, including a high damping capacity and compressive strength For this reason, grey cast iron is often used in bearing houses that absorb vibrations from rotating assemblies. Grey cast iron flows easily in its liquid state, so that it is often used to create ornaments and decorative designs on hearths and fireplaces. To some extent we can control the material properties by using various additives.
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Ductile iron, or spheroidal graphite iron, is a new material that was first applied industrially in the 1950s. Ductile iron starts out as grey cast iron, which is then treated with magnesium. The addition of magnesium causes the graphite to appear as spherical nodules, and not as flakes, when the metal solidifies. The graphite spheres are enclosed by pure iron, so that fractures cannot spread in the same way as they do through grey cast iron. Spheroidal graphite iron is a ductile material which is extremely strong. It is especially well suited to structures that need to tolerate heavy mechanical strain. In the same way as for grey cast iron, we can control the material properties by adding various substances to the alloy.
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Properties of alloys in grey iron
MATERIAL
QUALITY |
CHEMICAL ANALYSIS |
MECHANICAL PROPERTIES |
Type
NS |
C% |
Si% |
Mn% |
P% |
S% |
Mg% |
Cu% |
Ce |
Yield strength |
Tensile strength |
Elongation |
Hardness |
GREY IRON
NS 11100 |
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Re
(N/mm²)
min/max |
Rm
(N/mm²)
min/max |
A5(%)
min/max |
HB
min/max |
| SjG 150 |
3,50 |
2,30 |
0,60 |
0,010 |
<0,02 |
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4,08 |
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150/... |
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150-190 |
| SjG 200 |
3,40 |
2,10 |
0,60 |
" |
" |
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3,93 |
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200/... |
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170-210 |
| SjG 250 |
3,30 |
1,90 |
0,70 |
" |
" |
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3,78 |
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250/... |
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180-230 |
| SjG 300 |
3,10 |
1,80 |
0,75 |
" |
" |
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0,4/ 1,0 |
3,56 |
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300/... |
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190-250 |
Other similar standards/alloys - grey iron
Norway
NS 11100 |
HB |
Sweden
SIS |
Denmark
DS 11301 |
Germany
DIN 1691 |
Finland
SFS
H 11.51 |
Great Britain
BS 1452,
1977 |
USA
ASTM
A 4876 |
EU
EN
1561 |
| SJG 150 |
150/190 |
14 0115 |
GG 15 |
GG 15 |
GRS 15 |
Grade 150 |
Class 20B |
GJL 150 |
| SJG 200 |
170/210 |
14 0120 |
GG 20 |
GG 20 |
GRS 20 |
Grade 220 |
Class 30B |
GJL 200 |
| SJG 250 |
180/230 |
14 0125 |
GG 25 |
GG 25 |
GRS 25 |
Grade 260 |
Class 35B |
GJL 250 |
| SJG 300 |
190/250 |
14 0130 |
GG 30 |
GG 30 |
GRS 30 |
Grade 300 |
Class 45B |
GJL 300 |
Properties of alloys in ductile iron
MATERIAL
QUALITY |
CHEMICAL ANALYSIS |
MECHANICAL PROPERTIES |
| SG-IRON |
C% |
Si% |
Mn% |
P% |
S% |
Mg% |
Cu% |
Ce |
Yield strength |
Tensile strength |
Elongation |
Hardness |
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Re(N/mm²)
min/max |
Rm(N/mm²)
min/max |
A5(%)
min/max |
HB
min/max |
NS 11338
SjK 400.3 |
3,55 |
2,05 |
0,18 |
<0,02 |
<0,02 |
0,025
0,055 |
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4,07 |
250/(310) |
400/(500) |
18/(28) |
130/170 |
NS 11342
SjK 400 |
3,70 |
2,50 |
0,35 |
" |
" |
" |
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4,34 |
250/(320) |
400/(520) |
15/(28) |
135/180 |
NS 11350
SjK 500 |
" |
" |
0,50 |
" |
" |
" |
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" |
320/(440) |
500/(720) |
7/(17) |
170/230 |
NS 11360
SjK 600 |
" |
" |
0,65 |
" |
" |
" |
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" |
380/(520) |
600/(820) |
3(5)/10 |
195/250
(200/260) |
NS 11370
SjK 700 |
" |
" |
0,75 |
" |
" |
" |
0,4/
1,0 |
" |
440/(570) |
700/(960) |
2(3)/7 |
225/280
(230/300) | Figures in ( ), from Swedish Standard, SIS.
Other similar standards/alloys - ductile iron
Norway
NS |
HB |
Sweden
SIS |
Denmark
DS 11303 |
Germany DIN 1693 |
Finland
SFS 2113.
-75 |
England
BS 2789,
1973 |
USA
ASTM
A 536 |
EU
EN
1563 |
SJK 400.3
NS 11338 |
130/170 |
14 0717
(12)-02 |
0717 |
GGG 40.3 |
GRP 370 |
Grade 370/17 |
60-40-18 |
GJS 400
-18A LT |
SJK 400
NS 11342 |
135/180 |
14 0717 |
0716 |
GGG 40 |
GRP 400 |
Grade 420/12 |
60-40-18 |
GJS 400
-15A |
SJK 500
NS 11350 |
170/230 |
14 0727 |
0727 |
GGG 50 |
GRP 500 |
Grade 500/7 |
65-45-12 |
GJS 500
-7A |
SJK 600
NS 11360 |
195/250 |
14 0732 |
0707 |
GGG 60 |
GRP 600 |
Grade 600/3 |
80-55-06 |
GJS 600
-3A |
SJK 700
NS 11370 |
225/280 |
14 0737 |
0708 |
GGG 70 |
GRP 700 |
Grade 700/2 |
100-70-03 |
GJS 700
-2A |
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