ADI DAYS - Sven Lung

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



3

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



4

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



5

Fz: Resultant forceFc: Cutting forceFf: Feed forceFp: Passive force

vc: Cutting speedvf: Feed velocityve: 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



6

Summary5





Wear Formation when Turning Ductile Iron



7

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



8

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



9

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



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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



11

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



12

Summary5





Optimisation of Tool life in External longitudinal turning using Emulsion



13

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°

o

eff

ls

vc

fap

kr

HC-K20CNMA 120408Ti(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



14

Process: External turning (Emulsion)

Material: ADI 900Tool holder: MCLNL2525Tool geometry: CNMA/ CNMG 120408

Material removal rate: Q = vc • ap • fDepth of cut: ap = 2 mmCutting speed: vc = 240 / 320 m/minFeed: 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

9

rb = 60 µm

eff = -6°

o = 6°CNMA

eff = -6°

rb = 60 µm

o = 6°

eff = -1°12°

250 µm

CNMGeff = -1°

T =

9.4

min

vc = 320 m / minf = 0.2 mm

Q =

128

cm

3 /m

in

T =

7 m

in

vc = 240 m / minf = 0.4 mm

Q =

192

cm

3 /m

in

T =

10 m

in

T =

11 m

in

Q = + 50 %

T ≈ + 36 %

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



15

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



16

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/minFeed: f = 0.2 mmDepth of cut: ap = 2 mm

Cutting material: HC-K20Cutting insert: CNMA 120408Coating: Ti(C, N)/ Al2O3

Setting Angle: kr = 95°Clearance Angle: o = 6° Inclination Angle: ls = -6°

Austempering time: 30 min





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



17External longitudinal turning (ADI 900): vc = 240 m/min; f = 0.2 mm; ap = 2 mm; Emulsion; kr = 95°; o = 6°; ls = -6°; HC-K20, Coating: Ti(C,N)/ Al2O3, CNMG 120408 (eff = -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



18External logitudial turning (ADI 900, Emulsion, Criterion: VB = 200 µm): vc = 240 m/min; f = 0,2 mm; ap = 2 mm; kr = 95°; o = 6°; ls = -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, eff = -1°

HC-K20, eff = -6°

HC-K15, eff = -6°

HC-K15, eff = -6°

HC-K15, eff = -1°

HC-K20, eff = -1°

HC-K20, eff = -6°

Core material

Core material

Cast skin

Cast skin

Cast skin

Cast skin

500 µm

Agenda



19

Summary5





Project Overview



20

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 6336Teil 3

ISO 6336Teil 2

ISO 6336Teil 1

SN-Curves: Comparison of Variants ADI900 and ADI1200



21

Damage ADI900

Run Out ADI900

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

QOil = 1,5 l/minTOil,in = 90 °COil: FVA3 A 4% Anglamol

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

100000 1000000 10000000 100000000400

800

1600

Load Cycles / x106He

rtzi

an C

onta

ct P

ress

ure

/ MPa

Damage ADI1200

Run Out ADI1200SN-Curve ADI900SN-Curve ADI1200

Agenda



22

Summary5





Summary



23

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

Date post:	20-Jan-2017
Category:	Engineering
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ADI DAYS - Sven Lung

Engineering