Laser Surface processing-The features and the applications -

1)Introduction2) Heating process 3) Melting process

4) Laser vaporizing process5) Laser CVD & PVD

6)laser marking and engraving By Munehary KUTSUNA

Nagoya universityKutsuna@numse.nagoya-u.ac.jp

1.IntroductionType of lasers for surface processing

High power(45kW) Hig CO2 laser 10kW Nd:YAG laser with lump

• High power(6kW) diode laser • 10kW LD pumped solid state lasers • 4kW Disk laser• 10kW Fiber laser•

Beam Quality of laser beam

Types of Laser Surface processings

• Laser transformation hardening• Laser bending/forming• Laser solution treatment• Laser alloying• Laser cladding• Laser surface remelting• Laser CVD/PVD

2.Laser transformation hardening

Laser hardening of shaft

Since 1988 by Nissan

Laser hardening of crank shaft

for car

Microstructure of harden zone

Hardness distribution

Distance from surface

Hardness

Max.hardness of laser hardening zone

Laser hardening of clutch dram

3, Laser bending/forming

Laser forming of steel pipeNagoya Univ.

Experimental Setup of laser bending

Bending angle

Why the plate is bended by laser?

Materials propertiesIs important factor.

Prediction of bending angle

4.Laser solution treatment

5.Laser alloying;Carbonizing

Beam rotating device forSurface processing

Carbon distribution

Wear test of laser carbonized zone

Application of laser alloying for aluminum engine for motorcycle

6.Laser cladding

Laser cladding of engine valve seat

Laser cladding of copper alloy powder

Laser cladding of roll embosser

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• 3D Laser cladding using a robot for rapid prototyping and repairing

• We had an experiment oflaser cladding

Optical fiber

Powder Powder delivery delivery nozzlenozzle

Powder feeder

Shielding gas cylinder

For x-y-z positioning of focusing lens and powder delivery nozzle

レーザロボットシステムの構築

YAG laser system

6-axis robot

Powder Powder delivery delivery nozzlenozzle

Nozzle for laser cladding with powder feeder

Laser beam

Powder flow

Focus lens Center shielding gasOuter shielding gas

Clad layer Base metal

Two circular cones of copper were coaxially assembled.

Fig. Photograph of laser claddingsystem

Materials used

Table. Chemical composition of filler metal, SUS304 stainless steel

0.08 0.72 1.54 0.024 0.018 8.75 18.42 bal.

C Si Mn P S Cr Fe

Chemical composition , mass%

Ni

Table. Chemical composition of base metal, SM400B

0.40 1.38 0.0170.18 0.0045 bal.C Si Mn P S Fe

Chemical composition , mass%

Cladding condition

100 W(1ms, 90pps)Laser power

Spot diameterDefocusing distance

1.6 mm+1mm Ar : 10 ltr/minCenter shielding gas

Ar : 10 ltr/minOuter shielding gas

Travel speed 1.5– 7.5 mm/sec

Powder Flow Rate 5.6、9.6 and 12.8 g/min with Ar gas

Bead appearance ;SUS304

Effect of travel speed(SUS304)

Typical bead shape

タイプA タイプB タイプC

Effect of travel speed on penetration(SUS304)

Effect of travel speed on dilution(SUS304)

Process window for laser cladding of SUS304 powder

0.6

0.5

0.4

0.3

0.2

0.1

00 2 64 8

Travel speed, mm/sec

Thic

knes

s of

clad

laye

r, m

m50

40

30

20

10

0

Dilution, %

Optimum region

硬さに及ぼす走行速度の影響(SUS304）

Average: 220 Hv ~ 240 Hv

Laser cladding of Colmonoy #5 and FP160

耐摩耗性合金（Colmonoy No.5 及び FP160)を用いたレーザ肉盛

•耐摩耗性、耐衝撃摩耗性に優れた材料•自動車の排気バルブの肉盛などにも使用

Colmonoy No.5 0.65 3.75 11.5 2.504.25 bal.

C Si Cr BFe

Chemical composition , mass%

Ni

1.80 21.0 3.0 5.0

W Co

bal.FP160

Table. Chemical composition of filler metals

レーザ肉盛実験条件Laser condition

100 W(1ms, 90pps)Laser power

Spot diameterDefocusing distance

1.6 mm+1mm Ar : 10 ltr/minCenter shielding gas

Ar : 10 ltr/minOuter shielding gas

Travel speed 1.5– 4.5 mm/sec

8.42, 12.67 g/min; Colmonoy No.5Powder Flow Rate 4.67, 9.39 g/min; FP160

（Colmonoy No.5）

（FP160）

Effect of travel speed on clad thickness

(a) Colmonoy No.5 (b) FP160

Result of EPMA(Colmonoy No.5)

(b) Travel speed = 4.5 mm/sec(a) Travel speed = 1.8 mm/sec

Result of EPMA(FP160)

(b) Travel speed = 3.0 mm/sec(a) Travel speed = 2.25 mm/sec

Dilution of laser cladding

(a) Colmonoy No.5 (b) FP160

Multi pass cladding for rapid prototyping

Laser beam

Scanning direction

Scanning pattern

powder

Layer by layer

x

Example of laser rapid prototyping

Schematic drawing

Photograph of multi layer cladding

7.Laser surface remelting

Dull treatment by laser

Dull treatment for cladding of roll

8.Laser CVD/PVD

Laser CVD for circuit

Laser PVD for tools

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