Machining of Austempered Ductile Iron Challanges and Solutions · Austempering,-A-Technology-for-Substitution ADI$DAYS$$2016$$ 6th$$–7 th $October$$$$$Minerbe 1 Machining of Austempered

Austempering, A Technology for Substitution

ADI DAYS 2016 6th – 7th October Minerbe

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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

Agenda



2

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



3

▪ 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 Aγ

Chip

Work piece

Secondary shear zone (flank face)

Secondary shear zone (rake face)Primary shear

zone

βo

rb

Flank face Aα

Cutting speed vc

Feed rate f

Resolution of the Effective cutting speed and the resultant force



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Fz: Resultant force Fc: Cutting force Ff: Feed force Fp: Passive force

vc: Cutting speed vf: Feed velocity ve: Effective cutting speed

Feed motion (Tool)

vc

vf

ve

Fc

Fp

Ff

Rotational speed (Work piece)

Fz

▪ 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



5

Summary5





Wear Formation when Turning Ductile Iron



6

GJS-900-7 (ADI 900)

f = 0,2 mm ap = 1 mm

vc = 140 m/min t = 18,8 minG

JS-9

00-7

Criterion : Flank & Crater wear

Austenitic- Ferritic Matrix

GJS

-700

-2

Criterion : Flank wear

Perlitic Matrix

GJS

-400

-15 Crater wearFlank wear

Criterion : Flank wear

Ferritic Matrix

Cutting time

Cutting time

GJS-700-2 (GGG70)

f = 0,2 mm ap = 1 mm

vc = 260 m/min t = 6,8 min

GJS-400-15 (GGG40)

f = 0,2 mm ap = 1 mm

vc = 360 m/min t = 12,6 min

Wear mechanisms of Quenched and Temperd Steel and ADI



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Cutting parameters HM-K10 vc = 70 m/min f = 0,25 mm ap = 1,5 mm Dry Machining tc = 8,00 min

Source: C. Klöpper, Phd-Thesis RWTH Aachen

500 µm42C

rMo4

+QT

GJS

-900

-7

500 µm

500 µmetched

500 µmetched

Comparison of the Cutting Forces



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1000

1500

2500

3000

1 2 3 4

Cutting Force Oscillation vc = 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 A ap

f

kr

Direction of rotation

h kr

Related cutting force

fv! fv

!

Stages of the chip formation of ADI materials



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⑧⑦⑤

①First contact Start of deformation Crack initiation Sliding

End of sliding Segmentation⑥

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

③ ④②

Influence of Material Hardness on Wear and Tool life in dry Turning



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External longitudinal turning (Criterion: KT = 75 µm; VBmax = 300 µm): vc = 160 m/min; f = 0.2 mm; ap = 2 mm; dry; κr = 95°; αo = 6°; λs = -6°; γeff = -6°HC-K20,Coating: Ti(C, N)/ Al2O3, CNMA 120408;

ADI 900; T = 13,5 min

600 µm

GJS 700-2; T = 26,8 min

600 µm

Tool life T / min0 5 10 15 20 25

GJS 700-2 100 %

ADI 1200 15 %

GJS 900-7 50 %

ADI 1200; T = 3 min

600 µm600 µm

200 µm600 µm200 µm

ADI 1200; T = 3 min (etched)

Agenda



11

Summary5





Optimisation of Tool life in External longitudinal turning using Emulsion



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Em

ulsi

on

ADI 900

GJS 700-2

ADI 1200

Tool

life

T /

min

Cutting speed vc / (m/min)

Dry ADI 900

GJS 700-2

ADI 1200

10

100

2

30

60 40080 200 300

8

6

4

20

ADI 1200

ADI 900

GJS 700-2

= 6° = -‐6° = -‐6°

αo

γeffλs

vc f ap κr HC-‐K20 CNMA 120408 Ti(C, N)/ Al2O3

= var. = 0,2 mm = 2 mm = 95°

External longitudinal turning (KT = 75 µm; Vbmax = 300 µm):

Increase of Material removal rate and Tool life by adapted Feed, Cutting speed and Tool geometries



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Process: External turning (Emulsion) Material: ADI 900 Tool holder: MCLNL2525Tool geometry: CNMA/ CNMG 120408 Material removal rate: Q = vc • ap • f Depth of cut: ap = 2 mm Cutting speed: vc = 240 / 320 m/min Feed: f = 0,2 / 0,4 mm

Mat

eria

l rem

oval

rate

Q /

cm3 / m

in

0

50

100

150

200

0

3

6

12

Tool

life

T /

min

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rβ = 60 µm

γeff = -6°

αo = 6°CNMA

γeff = -6°

rβ = 60 µm

αo = 6°

γeff = -1°12°

250 µm

CNMGγeff = -1°

T = 9.4 min

vc = 320 m / min f = 0.2 mm

Q = 128 cm

3 /min

T = 7 min

vc = 240 m / min f = 0.4 mm

Q = 192 cm

3 /min

T = 10 m

in

T = 11 m

in

Q = + 5

0 %

T ≈ + 3

6 %

Increase of Tool life in Turning ADI 900 by Material-sided optimisation



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5

10

15

20

Tool

life

T /

min

Wall thickness: 20 mm




Nic

kel-C

onte

ntM

olyb

deni

um-C

onte

nt

Con

tent

of a

lloyi

ng e

lem

ents

/ %

0

1,0

2,0

3,0

4,0

0

External longitudinal turning (Tool life criterion: KT = 75 µm, VBmax = 300 µm):vc = 160 m/min; f = 0.2 mm; ap = 2 mm; dry; κr = 95°; αo = 6°; γeff = -6°; λs = -6°; MCLNR 2525M12; HC-K20, Coating: Ti(C, N)/ Al2O3, CNMA 120408;

Scatter from average value to maximum and minimum

Influence of Heat Treatment on Tool life when turning ADI



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0 2 4 6 8 10 12 14 16

Haltezeit Salzbad: 180 min

Tool life T / minExternal longitudinal turning (ADI 900; dry; Criterion: KT = 75 µm, VBmax = 300 µm): Cutting speed: vc = 160 m/min Feed: f = 0.2 mm Depth of cut: ap = 2 mm

Cutting material: HC-K20 Cutting insert: CNMA 120408 Coating: Ti(C, N)/ Al2O3

Setting Angle: κr = 95° Clearance Angle: αο = 6° Inclination Angle: λs = -6°

Austempering time: 30 min





Influence of the casting skin on cutting forces in roughing operations of ADI 900



16External longitudinal turning (ADI 900): vc = 240 m/min; f = 0.2 mm; ap = 2 mm; Emulsion; κr = 95°; αo = 6°; λs = -6°; HC-K20, Coating: Ti(C,N)/ Al2O3, CNMG 120408 (γeff = -1°);

Casting skin

Core material

T = 10 min

T = 10 min

1 mm

1 mm

Cut

ting

forc

es F

c / N

Cut

ting

forc

es F

c / N

Am

plitu

de ≈

700

N

500

1000

1500

0

Am

plitu

de ≈

70

N

500

1000

1500

0 t = 0,5 s

t = 0,5 s

Optimization of the roughing process of ADI 900 by using adapted tools



17External logitudial turning (ADI 900, Emulsion, Criterion: VB = 200 µm): vc = 240 m/min; f = 0,2 mm; ap = 2 mm; κr = 95°; αo = 6°; λs = -6°; MCLNR 2525M12; Coating: Al2O3 / Ti(C, N), CNMx 120408

Tool life T / min0 2 4 6 8 10 12 14

Comb cracks

Tcast skin = 10 min 1 mm

HC-K20, γeff = -1°

HC-‐K20, γeff = -‐6°

HC-‐K15, γeff = -‐6°

HC-‐K15, γeff = -‐6°

HC-‐K15, γeff = -‐1°

HC-‐K20, γeff = -‐1°

HC-‐K20, γeff = -‐6°

Core material

Core material

Cast skin

Cast skin

Cast skin

Cast skin

500 µm

Agenda



18

Summary5





Project Overview



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Evaluation of Test Results

Analysis of Wear

Calculation ISO6336

The aim of the project is to determine the contact fatigue of different ADI types (JS/900-8, JS/1200-3) and casted steels (AST)

by disk-on-disk and back-to-back testing

Investigation of Contact Fatigue

Disk-on-Disk

Back-To-Back

Aim

Quality of Specimen

Geometry & Roughness

ISO 6336 Teil 3

ISO 6336 Teil 2 ISO 6336

Teil 1

SN-Curves: Comparison of Variants ADI900 and ADI1200



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Damage ADI900

Run Out ADI900

■ Disk-on-Disk Testa = 42,05 mms1 = -28 % n = 3000 min-1

QOil = 1,5 l/min TOil,in = 90 °C Oil: FVA3 A 4% Anglamol

■ Specimenmaterial: ADI1200material: ADI900d1/2 = 42,05 mmRbal1/2 = ∞/166 mmRz ≈ 3 µm

Hertzian Co

ntact P

ressure / MPa

100

1000

10000

Load Cycles / x106

100000 1000000 10000000 100000000

Damage ADI1200

Run Out ADI1200SN-Curve ADI900SN-Curve ADI1200

Agenda



21

Summary5





Summary



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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

material allowance

Machining of Austempered Ductile Iron Challanges and Solutions · Austempering,-A-Technology-for-Substitution ADI$DAYS$$2016$$ 6th$$–7 th $October$$$$$Minerbe 1 Machining of Austempered

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