Solution strengthened ferritic spheroidal graphite cast iron according

Transcription

CastTech, Krefeld, 09.11.2012 – High Silicon Ductile Iron
-1-
Solution strengthened ferritic spheroidal
graphite cast iron according DIN EN 1563:
2012-03- Production, properties and
application
Dr.-Ing. Wolfram Stets; Dr.-Ing. Herbert Löblich;
Prof. Dr.-Ing. Peter Schumacher; Dr. Gert Gassner
IfG - Institut für Gießereitechnik
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-2-
IfG – Institut für Gießereitechnik
The branch institute of the German foundry industry
Product
quality
Economic
efficiency
Qualified
employees
Process
stability
Materials
properties
Environmental
protection and
health & safety
…..Single – source consultancy and research
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Initial situation
The revised standard DIN EN 1563 includes
three new cast iron grades:
EN-GJS-450-18
EN-GJS-500-14
EN-GJS-600-10
Material
EN-GJS-
450-18
500-14
600-10
Rm
[N/mm2]
min.
450
500
600
Rp0,2
[N/mm2]
min.
350 (310)
400 (320)
470 (370)
A [%] min.
18 (10)
14 (7)
10 (3)
Values in brackets:
comparable grades of
the conventional GJS
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-4-
The pearlite generating elements
Mn, Cu, Sn
in the conventional alloys determine the pearlite / ferrite ratio and
the mechanical properties.
EN GJS-600-3
EN GJS-600-10
Si contents between 3 and 4,3 % cause a solution
strengthened 100 % ferrite microstructure with high
mechanical properties
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Contents of the project
•
Static Mechanical properties in dependence on the Silicon content
•
Influence of carbide and pearlite generating elements (Mn, Cr, V) on
the static mechanical properties
•
Cast technological properties of high Silicon ductile iron
•
Influence of inoculation on microstructure in dependence on the
wall thickness
•
Investigation of the machinability of high Silicon ductile iron
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1) Static mechanical properties
Production of several cast samples for the materials investigation
Y4 sample
Radial sample
Wedge samples
Y2 sample
Samples for
shrinkage testing
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4,3%Si
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Separate cast Ysamples
700
Y-2
Y-4
[MPa]
Rm [Mpa]
600
500
400
300
200
100
0
2
3
4
5
6
Mass% Silicon
Massenprozent
Silicium
Rm and Rp0,2 pass through a maximum in dependence on the Si content
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Bruchdehnung
Elongation [%] [%]
4,3%Si
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Separate cast Ysamples
30
Y-2
Y-4
25
20
15
10
5
0
2
3
4
5
6
Mass% Silicon
Massenprozent
Silicium
In the neighbourhood of 4,3 % Si the elongation is decrasing
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HB Hardness
Mass% Silicon
Continous course of the hardness in dependence on Si content
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2) Influence of carbide and pearlite generating elements on the
static mechanical properties.
[MPa]
Added elements
Non
No influence of the added elements on the tensile strength
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4,3%Si
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Added elements
[MPa]
Non
No influence of the added elements on the yield strength
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Elongation [%] [%]
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Added elements
Non
The elongation is reduced with 0,6 % Cr
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Y2-Probe: 4,03% Si; 3,01 %C; 1,0 % Mn
Y2-Probe: 3,99 % Si; 3,01 %C; 0,63 % Cr
Rm: 581 MPa; Rp0,2: 486 MPa; A: 19,8 %
Rm: 649 MPa; Rp0,2: 506 MPa; A: 14,3 %
ca. 25% pearlite
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3) Cast technological properties of high Silicon ductile iron
Downsprue
with
turbulences
• Dross generating behaviour
Filter
Collecting bassin with scale
Filling of the bassin in dependence on the
time
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• Mold filling behaviour
Degree of filling in dependence on the Si
content and pouring temperature
No strong influence of Si
Cast harp sample
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Content of graphite
shape V + VI [%]
4) Influence of inoculation on microstructure in dependence on the
wall thickness
inoculant
Wall thickness (radial sample)
Different inoculants generate a wide range of microstructure
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Content of graphite
shape V + VI [%]
Inoculant 2
Wall thickness (radial sample)
Not only the inoculant determines the microstructure but also the Si content.
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Schematic correlation between inoculation technique, wall
thickness and microstructure
Content of graphite
shape V + VI [%]
Inoculation
good
Different
inoculants
Rising Si
content
Inoculation
poor
Wall thickness [mm]
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Graphite shape deviation comparable to Chunky graphite
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5) Investigation of the machinability of high Silicon ductile iron
Longitudinal turning of cylindrical castings (diameter
120 mm)- tool life at cutting speed 240 m/min
Tool life 50 – 60 % longer
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476
500
Freiflächenverschleiss in µm
450
400
271
288
350
300
min
Mittelwert
max
210
250
200
150
135
165
max
100
Mittelwert
50
0
min
GJS-600-3
GJS-600-10
Flank wear at the machining of planet carriers (300
kg), materials GJS-600-3 and GJS-600-10.
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Comparison of hardness and microstructure of GJS-600-3 with GJS-600-10
Hardness course
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Microstructure of GJS-600-3
etched
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Microstructure of GJS-600-10
etched
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6) Summarization
• The new grades of GJS give a optimized combination of strength and
thoughness (static loading).
• The worse influence of carbide generating elements is suppressed by
the high Si content.
• The castability of the Si alloyed GJS is not worse than the conventional
alloys
• The inoculation technology must be adapted to the new grades
• The high Si contents enhance the probability of graphite deviations
• The cyclic mechanical properties of the Si alloyed GJS grades are
higher
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Das vorgestellte IGF-Vorhaben der Forschungsvereinigung
Gießereitechnik e.V. FVG, Sohnstraße 70, 40237 Düsseldorf wurde
über die AiF Allianz Industrieforschung im Rahmen des Programms zur
Förderung der industriellen Gemeinschaftsforschung und –entwicklung
(IGF) vom BMWi Bundesministerium für Wirtschaft und Technologie
aufgrund eines Beschlusses des Deutschen Bundestages gefördert.
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Thank you !
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Solution strengthened ferritic spheroidal graphite cast iron according

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