Austempering, A Technology for Substitution ADI DAYS 2016 6 th – 7 th October Minerbe 1 Machining of Austempered Ductile Iron Challanges and Solutions - Austempering a technology for substitution - Prof. Dr.-Ing. Dr.-Ing. E. h. Dr. h. c. Dr. h. c. Fritz Klocke Dr.-Ing. Dipl.-Wirt.-Ing. Benjamin Döbbeler Dipl.-Ing. Sven Lung Bevilacqua, 6. and 7. October 2016
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Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
1
Machining of Austempered Ductile Iron Challanges and Solutions- Austempering a technology for substitution -
Prof. Dr.-Ing. Dr.-Ing. E. h. Dr. h. c. Dr. h. c. Fritz KlockeDr.-Ing. Dipl.-Wirt.-Ing. Benjamin DöbbelerDipl.-Ing. Sven Lung
Bevilacqua, 6. and 7. October 2016
Agenda
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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Summary5
Investigation of Contact Fatigue for ADI1200, ADI900 and AST4
Improvement of the ADI machining process 3
Machining properties of ADI2
Fundamentals in Metal Cutting1
Shear zones during chip formation
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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Primary shear zone: Transition from workpiece structure to chip structure
The material is getting deformed to a chip due to simple shear in the primary shearzone.
Secondary shear zone: Tensile load in combination with perpendicularly pressure and high temperature leads to strong deformation at the rake and flank face
The shear in combination with high pressure leads to a strong deformation in the border areas of the rake face and the flank face (secondary shearzone).
The boundary conditions during chip formation:- High temperatures in the contact zone (approx. 770-
1100°C) - High deformation rate (approximately 104 1/s)
Tool
Rake face A
Chip
Work piece
Secondary shear zone (flank face)
Secondary shear zone (rake face)Primary shear
zone
βo
rb
Flank face A
Cutting speed vc
Feed rate f
Resolution of the Effective cutting speed and the resultant force
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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Fz: Resultant forceFc: Cutting forceFf: Feed forceFp: Passive force
The vector of the effective cutting speed can be partitoned into two vectors Cutting Speed: In rotation direction Feed velocity: In feed direction
The machining force Fz can be partitioned in different components. Cutting force Fc: Force in cutting speed direction Feed force Ff: In Feed direction Passive force Fp
Agenda
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
6
Summary5
Investigation of Contact Fatigue for ADI1200, ADI900 and AST4
Improvement of the ADI machining process 3
Machining properties of ADI2
Fundamentals in Metal Cutting1
Wear Formation when Turning Ductile Iron
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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GJS-900-7(ADI 900)
f = 0,2 mmap = 1 mm
vc = 140 m/mint = 18,8 minG
JS-900-7
Criterion : Flank & Crater wear
Austenitic-FerriticMatrix
GJS-700-2
Criterion : Flank wear
PerliticMatrix
GJS-400-15 Crater wearFlank wear
Criterion : Flank wear
FerriticMatrix
Cutting time
Cutting time
GJS-700-2(GGG70)
f = 0,2 mmap = 1 mm
vc = 260 m/mint = 6,8 min
GJS-400-15(GGG40)
f = 0,2 mmap = 1 mm
vc = 360 m/mint = 12,6 min
Wear mechanisms of Quenched and Temperd Steel and ADI
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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Cutting parametersHM-K10vc = 70 m/min
f = 0,25 mmap = 1,5 mm
Dry Machiningtc = 8,00 min
Source: C. Klöpper, Phd-Thesis RWTH Aachen
500 µm
42C
rMo4
+QT
GJS
-900
-7
500 µm
500 µmetched
500 µmetched
Comparison of the Cutting Forces
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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1000
1500
2500
3000
1 2 3 4
Cutting Force Oscillationvc = 100 m/min, f = 0.2 mm
Cutting Time tc / ms
500
2000
Cut
ting
Forc
e F c
/ N
42CrMo4VEN-GJS-900-7
0
100
200
300
400
500
0 0.1 0.2 0.3 0.4Undeformed Chip Thickness / mm
Related Cutting Force Fc‘ / (N/mm)vc = 100 m/min (150 m/min for conventional GJS)
600
42CrMo4V
EN-GJS-400-15EN-GJS-700-2
EN-GJS-900-7
Rel
ated
Cut
ting
forc
e F‘
c / N
/mm
Fc' = 1133.3 h0.7006
Fc' = 1112.8 h0.6222
Fc' = 1099.6 h0.5732
Fc' = 2291.4 h0.9124
Cross section ofundeformed chip
Work piece
Toolb
fv
A ap
f
kr
Direction of rotation
h fv
kr
𝐹 𝑐 ′=𝐹 𝑐 /𝑏
𝐴=𝑏⋅ h=𝑎𝑝 ⋅ 𝑓Related cutting force
Stages of the chip formation of ADI materials
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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First contact Start of deformation Crack initiation Sliding
End of sliding
Segmentation
Crack initiationStart of deformation
Mat
eria
l spe
ed /
m/m
in
0
12,5
25
37,5
50
62,5
75
90
Source: C. Klöpper, Phd-Thesis RWTH Aachen
Influence of Material Hardness on Wear and Tool life in dry Turning
Investigation of Contact Fatigue for ADI1200, ADI900 and AST4
Improvement of the ADI machining process 3
Machining properties of ADI2
Fundamentals in Metal Cutting1
Summary
Austempering, A Technology for Substitution
ADI DAYS 2016 6th – 7th October Minerbe
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Tool life criterion by machining of ADI is the flank and crater wear. In comparison to a quenched and tempered ADI has a more abrasive tool wear. The dynamic tool load due to the chip formation leads to material fatigue of the tool. The thermal tool load can be reduced by using emulsion. The cutting speed should be decreased and the feed rate increased to achieve a high
tool life A high molybdenum content leads to a higher tool life scatter Machining the casting skin leads to a higher dynamic tool load due to the different