Laser Metal Deposition Overview - Advantage Austria · Images Courtesy of TWI . Copyright © TWI...

Copyright © TWI Ltd 2016

Laser Metal Deposition Overview

Dr Carl Hauser


What is it?

• Metal Deposition – Basic Principles

• Activity and Applications

• Case Studies

• Concluding Remarks

Contents


Laser Metal Deposition – Basic Principle

• Process: Filler material and a thin layer

of substrate melted by laser

• After Solidification: Fine microstructure

with a metallurgical bond with substrate.

• Scan strategies: Areas can be cladded

and volumes built by multiple layer

deposition.

• Material: Fe-, Co-, Ni-, Al-, Ti-alloys,

Cermets, mixed and metal matrix……….


Laser Metal Deposition – Main Features

• High precision cladding: Typical layer thickness 0.2 – 2.5mm

• Heat input: Low to moderate (minimal distortion/ small HAZ) and

<5% dilution with substrate.

• High cooling rates: 103-106 K/s> fine microstructure

• High potential: For automation, integration and unlimited work

envelope.


TWI LMD Hardware

Trumpf DMD 505 Gantry Cell

REIS RV60-40 Robot Cell

• Build Envelope: Maximum component

length 2.5m.

• Number of Axis: 5 + 2 (Trumpf) and

6+2 (Robot) (integrated rotary/tilt

manipulator)

• Lasers: 1.8kW HQ (High Quality) CO2

and Trumpf TruDisk 8002 (5.3KW) laser.

• Spot size: Variable and programmable

but with a 0.25mm (minimum) spot size

at focus position.

• Powder Feed: Sulzer Metco Twin-10-C

double hopper powder feeders (multiple

material capability)


• Functional Materials/Coatings • Hard wearing but often brittle

• Abrasive

• Light weight

• High temperature resistant (creep/corrosion ….)

• Repair • Tooling

• Legacy parts

• Turbine components (blades/vanes….)

• Machining errors in high value components

• 3D Structures (3D Printing) • Casings, pressure vessels, dome ended

• Honeycomb lattice, monolithic features, strengthening ribs

Applications Space


Functional COATINGS

Nickel-WC Deposited Edge*

100

mm

Internal/External Coatings

Triballoy T800 on X22 Steel

* Metal matrix composites (WC, cBN, Diamond).

Stellite 6 (Hardness Values (HV)

TIG MMA MIG PTAW LMD

380-440

370-415

360-430

385-450

500-600


Case Study: Turbine Shaft Cladding

• Background • Combat wear and corrosion of bearing journals

on a range of industrial gas turbine exit shafts. • Technical Challenge • Shaft material Ni alloy and martensitic stainless

steel • Cladding material is a Ni-Cr-Mo high tensile

steel. • Strict limits for defects (porosity, cracks), min

hardness levels and max Cr levels in deposit. • Trumpf CO2 laser deposition system using a

side feeder nozzle to gain access to the neck of the journal.

• Results • Journal life has been significantly extended > x2 • Six layers are deposited to give a 3.5mm

coating (Dia.) • Small series batch production of 70 shafts /

year (new and repair).


Case Study: WC Knife Edge

• Background

• Improve wear resistance of box cutter knife blades for cutting dry lining boards.

• Technical Challenge

• Develop procedures to deposit a WC (86%) in a CoCr metal matrix onto knife edge blanks

• Knife edge sharpened post LMD processing

• Results

• >> x10 increase in life of knifes for cutting dry lining boards (contain silicates, gypsum, grit – highly erosive)

• Automated laser deposition system designed to continuously deposit WC onto the edge of cutting knife blades (0.8mm thick) at a rate of hundreds of thousands per month (now in production @ 100,000 blades/day).

• LMD technology not only suitable for high value, low volume applications

Images Courtesy of TWI


100

mm

100

mm

Case Study: Steam Turbine Valve Stems

• Tribaloy T-800 is an extremely crack sensitive material but with high hardness (~750 Hv).

• Preheating to temperatures in excess of 600 degrees and controlled cooling would be required to prevent cracking

• Valve stem is a martensitic stainless steel which begins to scale above 550 degrees C.

• T800 had to be dilted with 10% nickel to enable crack free processing with 550 degrees C preheating.

• LMD deposited T800 + 10% Nickel gave 480 Hv

• T800 would be possible but not on a temperature sensitive substrate.


Case Study: ODS Alloys (Titanium Aluminide)

500 1000 1500 2000Temperature C

Sp

ecific

Str

en

gth

1m3 flexible argon chamber with induction coil preheating

100mm long Ti-Al (non ODS MA powder)

Ti-Al Processing with no temperature control


Ti-Al (ODS) Material Properties

Process and Material Condition HV ± 1s

SPS OX 1123 K/12 h 441 ± 29

1673 K/15 min + 1123 K/12 h 409 ± 26

SPS OX ODS

as SPS 505 ± 18

1123 K/12 h 477 ± 16

1573 K/15 min + 1123 K/12 h 471 ± 23

1673 K/15 min + 1123 K/12 h 485 ± 15

LMD OX ODS

as LMD 564 ± 61

1123 K/12 h 546 ± 38

1573 K/15 min + 1123 K/12 h 469 ± 25

LMD GE48-2-2

as LMD 512 ± 45

1123 K/12 h 410 ± 19

1573 K/15 min + 1123 K/12 h 358 ± 15

After 1000 hour corrosion tests

• OXIGEN Ti-Al (MA) 2x more resistant to oxidation than commercial TiAl powder (spark plasma sintered - solid state consolidation)

• LMD Ti-Al + ODS gives >> corrosion resistance than SPS samples


Tooling, turbine blades/vanes

LMD Activity - REPAIR

Cutting tools (M2 deposit on M35 substrate)

Vane Edges Ti- Alloy

Stainless Steel Seal

Teeth Repair (Tool Steel)


Case Study: Repair of Broaching Tools

• Teeth vary in length and depth

• Access to the repair site is limited

• Substrate material: M35 steel.

• Deposited powder material: M2 steel, a high speed molybdenum-tungsten tool steel alloy

• Current baseline hardness requirement 64-67 HRC (substrate and teeth).

• Significant prolonged heating during deposition will soften tool – post heat treatment will compromise cost effectiveness of any repair solution.

• No defects are permitted, including cracks, pores or unfused material.

Individual teeth wire eroded to simulatemissing teeth


Deposition with no substrate temperature control


Deposition with substrate (induction coil) temperature control

• Surviving the post deposition grinding process was the first step toward repair validation

• Grinding trials of teeth built with no/ineffective preheating would cause teeth to sheer from the substrate.

• Dilution zone found to be less than 200µm, measured at approximately 150µm.

• Heat affected zone measured to be less than 500µm.

• Hardness results obtained between 62 - 64 HRC.

• First iteration of deposited teeth survived first broaching cycle.


LMD Activity – 3D STRUCTURES

Combustor Case (Helicopter – 300mm Dia) Generic Demonstrator (>>600mm Dia)

Gas Turbine Part (300mm Dia) TWI ToolCLAD™ LMD CAM Software

Nickel Super Alloys


Results

Tensile Testing (ASTM E8/E8M)

Sample ID Material

Sampling Direction

Date

Testing Temp [°C]

W0 [mm]

T0 [mm]

Wf [mm]

Tf [mm]

L0 [mm]

Lf [mm] UTS [Mpa]

Ys 0.2% [Mpa]

Ys 0.02% [Mpa]

Elongation 4D [%]

Area reduction [%]

E [Mpa]

2016-1152-0110

In718 DMLM

Longitudinal - Z Axis

07/11/2016

21 6,02 1,85 5,87 1,60 25,00

29,30 1027 779 868 17 16 124157

2016-1152-0120

In718 DMLM

Transversal - Z Axis

07/11/2016

21 5,97 1,86 5,92 1,80 25,00

26,00 706 510 608 4 4 123816

• Wall deviation from CAD ± 0.3mm • Surface finish 15-20µm RA • Wall thickness 0.84µm ± 0.1µm


Inspection and Validation

Powder flow / laser focus sensor


Summary

• Versatile application fields in different industrial sectors

• New product functionalities are possible

• Geometry and mechanical properties of LMD and conventional manufacturing processes are comparable

• Time compression over existing manufacturing (months and weeks to hours)

• LMD manufacture can be economical

• Suitable for small batch and mass production

• Systems/Technology Integration (inspection, sensors, heat treatment, production line………)


Contact

Dr Carl Hauser

Consultant - Technology (Additive Manufacturing)

Joining Technologies Group

TWI Technology Centre Yorkshire

Advanced Manufacturing Park, Wallis Way, Catcliffe, Rotherham. S60 5TZ, UK

Tel: +44 (0)114 269 9046 E-mail: [email protected]

Web: www.twi-global.com

The research leading to these results has received funding from the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement no. 310279 (OXIGEN).

mailto:[email protected]

http://www.twi-global.com/



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