This material is based upon work supported by DOE under award number DE-FG02-08ER84958 Made in U.S.A. Weld Puddle Forming and Shaping for Enhanced Laser Cladding John M. Haake Titanova, Inc St. Charles, Missouri, USA www.titanovalaser.com LAM 2012
Made in U.S.A. Cladding or Weld Overlay Cladding or weld overlay makes use of a heat source to melt and fuse [weld] onto the substrate of a component a material that has different and beneficial metallurgical properties. This allows one to cost effectively customize the surface properties • Corrosion resistance • Erosion resistance • Wear resistance = Laser Hardfacing 2
Made in U.S.A. Methods for Laser Cladding • Powder cladding – Preplaced and Collinear • Thermal Spray and laser fuse • Wire feed cladding – Vertical wire feed cladding • Hybrid processes – Hot wire feed • LISI - Laser Induced Surface Improvement 3
Made in U.S.A. Clad Profile Comparison Dilution held constant 3 23 q q Wetting angle Gaussian shape beam – round spot 24 q Rectangular shape beam More desirable 3 25 q Line shape beam 3
Made in U.S.A. Flatter Clads = More Dilution 1:1 aspect ratio laser beams Typical Cross-sections of clad layers produced by means of powder feed cladding with varying energy density= power X velocity feed rate constant at 5mm/sec . More dilution with the substrate as the power Increases with same surface speed And Less Defects!
Made in U.S.A. Clad Morphology Dilution held constant Gaussian Profile Rectangular • Less risk of entrapped pores Profile Line Profile
Made in U.S.A. Benefits of Diode Laser Cladding • Welded 100% dense = No porosity • Very Low dilution = High Corrosion resistance • Small heat affected zone = less distortion • High quench rates = finer grain structure = higher • corrosion potentials • Line Source allows for much wider thinner clads • Much smoother clads = less post machining • High Efficiency • Production worthy enabling one piece flow • Highly controllable • Smaller wavelength = higher photon energy = More absorption – Enables wire feed cladding – Enables strip cladding – Enables spray and fuse cladding • Small Size – Enables in-field cladding 7
Focus Configuration for Top-Hat Line Made in U.S.A. Source 12 X < 0.4 mm line @ focus - 125 mm Process Axis for heat treating, cladding, paint stripping, surface melting, composite manufacturing Process axis for autogenous welding, wire feed welding and brazing The line source is necessary to achieve thin flat low dilution clads. 8
Made in U.S.A. Fast Lensed Direct Diode Laser This is the beam profile from a ISL-2000LHD where the FWHM is approximately 6 mm X <400 microns. There is no additional improvement in the fast axis [short axis of the focused spot] by double macro lensing. Note the broader wings
Laser Cladding - What is Desirable Made in U.S.A. Job Shop Perspective • Thin flat low dilution clads • Increased deposition efficiency without loss of good morphology • Material insensitivity • Base material insensitivity • Gas coverage insensitivity • Base material shape insensitivity • Base material position insensitivity • Edge definition • Zero defects • System robustness 10
Made in U.S.A. Increased Deposition Efficiency It is desirable to have high deposition efficiency without loss of surface morphology AND Low Dilution 6.0 lbs. 6.0 lbs. 4.7% Fe 7.0 lbs. 8.8 lbs. 3.0% Fe 9.2 lbs. 12.3 lbs. 0.7% Fe 80/20 NiCr 0.1% Fe 4000 Watts line source cm 2 /Watt NOT kg/hr. 11
Overlap Necessary for Good “Tie - in” Made in U.S.A. It is typically necessary to apply more heat to achieve good morphologies More Dilution Machine surface For clean up First Pass Tie in Second pass Third pass Required overlap This material is the Step over distance tie-in material
Made in U.S.A. Process Material Insensitivity Is desirable to have a clad process that is insensitive to base material chemistry, clad materials chemistry, gas coverage, and environment 13
Made in U.S.A. Mechanical Insensitivity Base Material shape - It is desirable to achieve the same morphology over 3D surfaces Clad Material Shape – It is desirable to achieve the same morphology independent of the clad material shape 14 Hot Wire Laser Cladding
Made in U.S.A. Weld Position Insensitivity 5G Welding It is desirable to achieve the same clad morphology and dilution independent of weld position. 15
Made in U.S.A. Edge Definition Pore – incomplete fusion Inside edge requirement is for no pores for 100% cleanup • Requires different laser parameters • Different beam shape Inside Edge • Higher dilution • Separate process step Outside Edge Need clad to extend over edge for good clean-up • Requires different laser parameters • Different beam shape • Higher dilution – Edge melting • Separate process step 16
Made in U.S.A. Zero Defects Rework = 17
Made in U.S.A. System Robustness • Highest deposition rate = High power High Power = Big Problem! 18
Made in U.S.A. KISS Principal No way in a job shop environment! 19
Made in U.S.A. Separation of Variables Primary Laser $ Robust High power Laser cladding systems • Maximized High power lasers • Maximized deposition rates WELD puddle creator • Extensive peripheral cooling • Expensive Cladding nozzles optimized for high powers • Peripheral Cooling • Gas coverage WELD puddle manipulator Secondary lower power laser Optimized for flexibility Optimized for beam manipulation Independent from Primary laser Not collinear with Primary laser Inexpensive 20 Patent Pending
Made in U.S.A. Surface Tension = Primary Force • The Primary laser is the “work horse” it melts the clad material and creates the weld puddle • The Secondary low power laser is used to influence the weld puddle • Maintaining a molten state is a strategic location longer • Affecting surface tension properties in a beneficial way 21
Optimized Shape for “Tie - in” Made in U.S.A. Clad progression Step over distance d s Overlap distance d o Patent Pending
Made in U.S.A. Laser Weld Overlay Puddle Shaping Robust High Power Laser Lower power laser Molten Weld Overlay puddle Patent Pending
Examples of 4000W Line Cladding Source Made in U.S.A. with Varying Secondary Laser Power 0 Watts Secondary Laser on Right 110 Watts 36:1 210 Watts 19:1 632 Watts 6:1 Not optimized 1050 Watts 4:1 24 Patent Pending
Made in U.S.A. Outside Edge Definition 4000W diode laser Line beam LaserLine fiber coupled 300mm FL Edge Work piece Patent Pending
4000W Line Source Cladding with Made in U.S.A. Secondary Laser on Edge 0 watts 400 watts 800 watts Not optimized 26 Patent Pending
Potential Benefits of In-situ Puddle Made in U.S.A. Forming and Shaping • Increase deposition rates = cm 2 /W • Improved morphology [flatter thinner clads] • Lowering dilution [ Less heat for tie in] • Clad material independence • Based material independence • Cover gas independence • Base work piece shape independence • In situ defect mitigation [fixing blow holes] • Outside Edge definition • Edge definition around holes • Inside fillet definition • In Situ defect mitigation • Thinner clads with less defects • Control of solidification cracking issues • Improving wire feed laser cladding • 3D build up 27 Patent Pending
ISO:9001:2008 Certified Made in U.S.A. ASME S,U and R Stamp Certified Thank You Titanova, Inc. This material is based upon work supported by DOE under award number 28 DE-FG02-08ER84958
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