Latest Development Work on Induction Assisted Laser Cladding Processes

Transcription

1 Latest Development Work on Induction Assisted Laser Cladding Processes C. Leyens 1,2, F. Brückner 1, S. Nowotny 1 1 Fraunhofer Institute for Material and Beam Technology (IWS), Dresden, Germany 2 Dresden University of Technology, Germany

2 Induction assisted laser cladding Outline introduction laser cladding and induction heating industrial applications summary and outlook

3 Laser cladding in manufacturing technology Laser Cladding & Build-Up Welding Performance & Applications highest precision and lateral resolution 50 µm near net shape material deposition in 2D and 3D Surface cladding beneficial coating properties: 100% dense, adhesion strength tensile strength dynamic fatigue behavior, minor heat input, low distortion Repair but: high investment and direct operation costs, low deposition rates, low productivity Direct Manufacturing limitations for large-area claddings, large material build-up, simple and economically priced applications

4 Energy distribution of a typical laser cladding process Part 1: beam delivery Energy distribution in laser cladding laser source optics in Watt

5 Energy distribution in laser cladding Energy distribution of a typical laser cladding process Part 2: process zone laser source radiation power after optics optics process

6 Energy distribution in laser cladding Energy distribution of a typical laser cladding process Part 2: process zone 1133 only a few percent of the radiation are used for the process in Watt reduction of required energy in the process zone lead to a strong reduction of laser power

7 Process improvements by additional heat sources aim: increasing the Productivity and Efficiency by means of combined energy sources additional heating of the coating material sharing the process energy: - high-efficient energy supply to heat / melt the cladding material wire or powder - laser energy used for the localization of the cladding process energy sources: - induction - electrical resistance - autogenous flame - radiant heat additional heating of the substrate influence on the process energy balance: - reduced cooling rate - reduced energy losses energy sources: - pre-heating in a furnace - second laser beam source - plasma heat source -flame - inductive preheating of complete substrate - local inductive energy supply

8 Process improvements by additional heat sources aim: increasing the Productivity and Efficiency by means of combined energy sources highest losses of process energy into the substrate additional heating of the substrate beneficial additional heating of the substrate influence on the process energy balance: - reduced cooling rate - reduced energy losses energy sources: - pre-heating in a furnace - second laser beam source - plasma heat source -flame - induction heating

9 Process improvements by additional heat sources additional heating of the substrate energy sources act on the surface of the substrate - traditional heating by a flame - second laser beam source - plasma heat source energy sources with heat intrusion into the depth of the substrate - pre-heating in a furnace - inductive pre-heating of complete substrate - local inductive energy supply reduction of temperature gradients in all axes necessary 1 rapid heating by directly coupled energy sources necessary for efficient processing 1 Brückner et al., J. therm. spray tech., 2007, 16(3)

10 Process improvements by additional heat sources reduction of temperature gradients in all axis necessary 1 rapid heating by directly coupled energy sources necessary for efficient processing local and directly integrated inductive energy supply 1 Brückner et al., J. therm. spray tech., 2007, 16(3)

11 Induction assisted laser cladding Principle of tailored temperature distributions temperature profile at laser cladding without Cross section of a laser weld track and with additional heating: extended t8/5 cooling time minor temperature gradients at 500 C compensation of heat conduction into work piece by inexpensive inductive energy

12 Hybrid cladding head High-performance cladding using the IWS COAXpowerline technology hybrid cladding head with integrated inductive energy supply coaxial powder delivery specially shaped inductors, based on simulations compatible to lasers up to 10 kw, preferably diode lasers

13 Hybrid cladding head Inductor design inductor design strongly dependent on work piece geometry process parameters materials computer calculated design of the inductors

14 Process results brittle coating materials Stellite 20 on AISI 1045 conventional laser cladding hardness 60 HRC laser cladding with local simultaneous inductive preheating (up to 700 C)

15 Process results productivity and efficiency laser cladded polished cross section without induction deposition rate: 2,4 kg/h Fe-based coating material laser cladding with local and simultaneous inductive preheating up to approx C deposition rate with local preheating up to C: 4,8 kg/h perpetuation of typical laser-related coating properties

16 Process results productivity and efficiency Increasing of deposition rate increased cladding rate through additional inductive heating example: Stellite 21 onto Steel laser power induction power deposition rate 8 kw kg/h 8 kw 12 kw 14.5 kg/h

17 Process results productivity and efficiency Reduction of costs reduced laser power through additional inductive heating example: Stellite 21 onto steel laser power induction power deposition rate 10 kw 0 8 kg/h 4 kw 12 kw 8 kg/h

18 Coating of big engine components experimental setup: diode laser laser spot 6 mm COAXpowerline cladding unit Industrial applications for high-power laser cladding laser power 4 kw 42C on steel v s = 1300 mm/min powder mass rate 40 g/min without induction powder efficiency 95 % doubled deposition rate with induction cross section without induction: cross section with induction:

19 Industrial applications for high-power laser cladding Repair of ship drives large-area repair of ship drives: 6 kw diode laser and IWS COAX8 nozzle current example representing a record in long-run cladding using IWS cladding technology: - propeller shaft of a passenger liner: 11 m length, 26 t weight. - deposition of 300 kg Stellite material in operation time of 100 hours. - meanwhile the ship is back at sea. source: Roussakis S.A. Ship Repairs strong increase of deposition rate by induction assistance deposition rates > 10 kg/h

20 Summary & Outlook increased deposition rate under perpetuation of laser-typical coating quality, potentially up to 30 kg/h high cladding rates even at lower laser power e. g. 4 kw Laser + 12 kw induction = 8 kg/h Co-based Stellite 21 crack-free deposition of non-weldable materials cost reduction by reduced investment costs, reduced production time, and advanced product s properties corrosion protection of large cylindrical parts, e. g. off-shore applications hardfacing of tools for the oil and mining industries

21 Latest Development Work on Induction Assisted Laser Cladding Processes Thank you for your attention! Contact: Prof. Dr. Christoph Leyens Fraunhofer IWS Winterbergstraße Dresden, Germany Phone Fax