induction hardening of gearwheels made from … 1627 workshop hannover, 30.09.-02.10.13 induction...
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IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Induction hardening ofgearwheels made from42CrMo4 hardening andtempering steel byemploying water-air spray coolingProject A3 IRTG 1627 „Virtual Materials and Structures and their validation“
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Induction hardeningPrincipleHardening of the surface layer
Heating for ferrite-austenite transformation
Rapid cooling for martensite formation
Heating duration of 0.1 s to 1 s
No phase transformation in the core
AdvantagesEnergy saving
Increase of wear resistance and fatigue strength
Minimization of size changes
Reduction of post-hardening machining Time-temperature profiles duringinduction hardening
900
Time in s
Tem
pera
ture
in °
C
1
surface
core
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Induction heating by simultaneous dual frequency method
Induction heating with MF Induction heating with HF
Working principleSimultaneous transmission of two oscillating electromagnetic
fields to a component surface layer
Tooth crest region: high frequency (HF) of 150 kHz to 350 kHz for hardening depths of 0.3 mm to 1 mm
Tooth root region: middle frequency (MF) of 10 kHz to 25 kHz for hardening depths up to 2 mm
A: Inductor current (HF, MF)B: HF-, MF-currents in the workpieceC: Heating of tooth crest by HF and of
tooth root by MFσ: Current penetration depth
Heating by an inductor
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
QuenchingState of the artInduction hardening by employing water-polymer solutions
Soft spot formation
Complicated handling
Bad skin compatibility of polymer solutionsAlternativeSubstitution of water-polymer quenching by water-air spray cooling
Water-air spray coolingGood controllability of the quenching processSelf-tempering (tempering from the residual heat)
Renunciation of polymer-solutionEnviromental compatibilityCost saving
Low distortion
Quenching by water-polymer solution
Quenching by water-air spraycooling
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Problem definition
Motivation Complicated handling of the quenching process by water-polymer solutions
High procurement and disposal costs of polymer-solutions
Need of an economic quenching method with high controllability
Until now engineering of spraying fields is based on empirical investigations
Spraying field concept for induction hardening machine
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Project objectives
Integration of water-air spray cooling in the process of induction hardening
Numerical model of induction hardeningby water-air spray cooling Consideration of thermal, microstructural and
mechanical interactions
Model implementation in commercialsimulation software ANSYS Workbench 13.0 Macros in Ansys Parametric Design Language (APDL)
Simulation results verification by experiments
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Experimental setup and test workpieceSprayfield Variability of nozzle number from 6 to 12 Water and air pressure adjustable from
0.1 MPa to 0.6 MPa Variability of distance between the workpiece
and the nozzles Control by an industrial PC using LabView
Spur and helical gearwheels of 42CrMo4
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Induction hardening by employing spray cooling
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Experimental results
water-polymer water-air sprayResidual stresses
Hardness profiles in the tooth crestMacrograph of induction hardened gearwheelby employing spray cooling
Distortion
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Cost analysis of the quenching process
0
1000
2000
3000
4000
5000
6000
7000
calc. depreciation calc. interest room costs energy costs maintenance andrepair costs
Mac
hine
rela
ted
over
head
cos
ts in
€/a spray field
polymersprinkler
Machine-hour schedules Spray field approx. 4 € Polymer sprinkler approx. 5 €
Quenching costs per gear0.0078 €0.01 €
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Self-tempering (tempering from the residual heat)
Residual stresses
Distortion
Tempered martensite in the tooth crest
Hardness profiles in the tooth crestFurnace tempering Self-tempering
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Model-relevant processes
Induction heating
Quenching by water-air spray cooling
Microstructure
Temperature
Temperature
Residual stresses
DistortionHardness
11 Temperature induced
phase transformation2
2Transformation heat
3
3 Thermal stresses
4 Deformation heat
4
5
5
Transformation stresses6
6
Stress induced transformation
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Temperature profile approximation after heating
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Verification of heating simulation results
1 2 34
5 6
Measured surfacetemperature
EXP [°C] FEM [°C]926.38 932.64
Point 1 Point 2 Point 3 Point 4 Point 5 Point 6
EXP [°C] 828.60 726.40 599.50 999.50 414.70 56.90
FEM [°C] 831.91 724.24 615.20 854.56 369.47 44.38
Simulated surfacetemperature
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Modelling of austenite formation
Volume fraction of austenite fordifferent heating rates [Miokovic et al. 2006]
6000 K/s
Variable Valuea -3.04E-12b 1.77E-08c -4.40E-05d 0.06083996e -50.4051351f 25039.0195g -6905494.06h 815651113
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Modelling of spray cooling
Temperature dependent heat transfercoefficients during quenching [Krause et al. 2008]
Temperature development during cooling
Wär
meü
berg
angs
koef
fizie
nt in
W m
-2K
-1
Temperatur in °C
0 100 200 300 400 500 600 700 800 9000 100 200 300 400 500 600 700 800 9000
5000
10000
15000
20000
25000
0
5000
10000
15000
20000
25000
1
2
3
4
5
6
7
Wasserdruck Luftdruck1 0,5 MPa 0,3 MPa2 0,6 MPa 0,5 MPa3 0,6 MPa 0,3 MPa4 0,6 MPa 0,6 MPa5 0,3 MPa 0,6 MPa6 0,3 MPa 0,3 MPa7 0,1 MPa 0,3 MPa
Water Air
Temperature in °CHea
ttra
nsfe
rcoe
ffici
enti
n W
·m-2
K-1
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Verification of cooling simulation results
T, °C
T, °CT, °CT, °C
T, °CT, °C
t, s t, s t, s
Point 1
Point 4
Point 2
Point 5
Point 3
Point 6
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Modelling of austenite-martensite transformation
The Koistinen-Marburger equation:ξM = 1 – exp[-k(Ms – θ)]
ξM - martensite fractionk - constant related to steel compositionMs - martensite starting temperature
θ - temperature
Martensite formation during cooling
TTT-diagram of 42CrMo4 steel for continuous cooling[Werkstoffdatenblatt 42CrMo4 (1.7225) 2010]
Model assumption
No diffusional phase transformation
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Modelling of hardness
Variable Valuea 324.878598b -0.00862882c 3.24E-05
Relationship between the hardness and the martensite fraction[Nürnberger 2010]
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Verification of hardness simulation results
Schematic of hardness measurements Tooth crest
Tooth flank Tooth root
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Modelling of residual stresses and distortion
(εij)tot = (εij)el + (εij)pl + (εij)th + (εij)tr + (εij)
(εij)tot total strain
(εij)el elastic strain
(εij)pl plastic strain
(εij)th thermal strain
(εij)tr transformation induced strain
(εij) transformation induced plasticity
Elastic-plastic model
Model assumptions
Low deformation heat
No stress induced transformation
tp
tp
Distortion Residual stresses
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Contents
Introduction
Motivation
Modelling of spray cooling and verification
Objectives
Conclusion/Outlook
Experimental investigations
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Conclusion/Outlook
ConclusionSubstitutionability of water-polymer quenching by water-air spray cooling in the
process of induction hardening was proved
Economic analysis of the quenching process
Self-tempering by employing spray cooling
Model describing the quenching process by water-air spray cooling after inductionheating was presented
Consideration of thermal, microstructural and mechanical interactions
Simulation results were verified by experiments
OutlookWear resistance and fatigue strength behaviour
Modelling of self-tempering
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
Thank you for your attention!
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
ReferencesKoistinen, D.P., Marburger, R.E.: A general equation prescribing the extent of the austenite-martensite transformation in pure iron-carbon alloys and plain carbon steels. Acta Metallurgica, Vol. 7, pp. 59 – 60, 1959
Krause, C., Wulf, E., Nürnberger, F., Bach, F.-W.: Wärmeübergangs- und Tropfencharakteristik für eine Spraykühlung im Temperaturbereich von 900-100 °C. Forschung im Ingenieurwesen, Vol. 72, pp. 163 – 173, 2008
Miokovic, T.; Schulze, V.; Vöhringer, O.; Löhe, D.: Prediction of phase transformations during laser surface hardening of AISI 4140 includingthe effects of inhomogeneous austenite formation. Materials Science and Engineering A 435-436, pp. 547-555, 2006
Nürnberger, F.: Vorhersage von Mikrostruktur und mechanischen Eigenschaften präzisionsgeschmiedeter Bauteile bei einer integriertenWärmebehandlung. Dissertation, Gottfried Wilhelm Leibniz Universität Hannover, 2010
Rodman, D., Krause, C., Nürnberger, F., Bach, Fr.-W., Haskamp, K., Kästner, M., Reithmeier, E.: Induction Hardening ofSpur Gearwheels Made from 42CrMo4 Hardening and Tempering Steel by Employing Spray Cooling. Steel Research International,Vol.82, Nr. 4, pp. 329 – 336, 2011
Gretzki, T.; Rodman, D.; Wolf, L.; Dalinger, A.; Krause, C.; Hassel, Th.; Bach, Fr.-W.: Economic surface hardening by spray cooling.HTM - Journal of Heat Treatment and Materials 66, Nr. 5, pp. 290–296, 2011
Rodman, D.; Krause. C.; Nürnberger, F.; Bach, Fr.-W.; Gerdes, L.; Breidenstein, B.: Investigation of the surface residual stresses inspray cooled induction hardened gearwheels. International Journal of Materials Research, Vol. 103, Nr. 1, pp. 73-79, 2012
Rodman, D.; Nürnberger, F.; Dalinger, A.; Schaper, M.; Krause, C.; Kästner, M.; Reithmeier, E.: Tempering Induction Hardened42CrMo4 Steel Helical Gearwheels from Residual Heat Using Spray Cooling. Steel Research International, pp. 1-11, 2013,DOI: 10.1002/srin.201300133
Rodman, D.; Boiarkin, V.; Nürnberger, F.; Dalinger, A.; Schaper, M.: Modeling of Spray Cooling during Induction Hardening of Spur Gearwheels Made from 42CrMo4 Hardening and Tempering Steel. Steel Research International, pp. 1-15, 2013, DOI: 10.1002/srin.201300201
Schwenk, W.R.: Simultaneous Dual-Frequency Induction Hardening. Heat Treating Progress, April/May, 2003
IRTG 1627 Workshop Hannover, 30.09.-02.10.13
ReferencesWeise, A.: Entwicklung von Gefüge und Eigenspannungen bei der thermomechanischen Behandlung des Stahles 42CrMo4. Dissertation,Technische Universität Chemnitz, 1998
Werkstoffdatenblatt 42CrMo4 (1.7225). Dr. Sommer Werkstofftechnik GmbH, Anwendungsinstitut zur Einsatzoptimierung von Werkstoffen, Verfahren, Wärmebehandlung, Issum, 2010