Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 1

Shot Peening

SP

Cavitation S Peening®

Shotless

S S Shock wave

S Smooth surface

S SOYAMA

Cavitation S Peening®

CP

Hitoshi SOYAMA Department of Nanomechanics, Tohoku University

Suppression of Crack Initiation of Metallic Materials

by Using a Cavitating Jet

October 10th, 2014, Sendai

Cavitating jet

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 2

“Cavitation Peening” and “Water Jet Peening”

* D.Kirk, The Shot Peener, Vol. 28, No. 3 (2014), pp. 22-32.

Water Jet Peening Water Jet Shot Peening

Schematic representation*

Potential core

In Water High-pressure

Droplets

Cavitation

impacts

Cavitation

Developing region

Collapsing region

Collapsing region

Nozzle

Cavitation Peening (Cavitation Shotless Peening)

*H.Soyama, The Shot Peener,

Vol. 28, No. 3 (2014), pp. 16-20.

Droplet and/or shot impacts Cavitation impacts

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University

0

0.1

0.2

0.3

0.4

0.5

0.6

0 100 200 300 400

3

Developing region

Of vortex cavitation

Collapsing region of

vortex cavitation

Surface

Cloud cavitation

Ring erosion

Vortex cavitation

In Water

Pressurized

water

Droplets

Collapsing region of

vortex cavitation

Cavitation

impacts

Inve

rse

of

cu

rva

ture

1

/r

m-1

Normalized standoff distance s/d

p1 = 300 MPa, d = 0.4 mm

p1 = 30 MPa, d = 2 mm

Droplets

impacts

Cavitation impacts

Droplets

impacts Cavitation impacts

Arc

he

igh

t H.Soyama,

Mechanical Engineering Review,

Vol. 2, No. 1 Feb. 2015, in press.

“Cavitation Peening” and “Water Jet Peening”

d

Standoff distance s

Potential core

p1 = 300 MPa

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 4

𝑠𝑜𝑝𝑡

𝑑≧ 1.8 𝜎−0.6

𝑠𝑜𝑝𝑡

𝑑＜1.8 𝜎−0.6

Cavitation Peening

Water Jet Peening

H.Soyama,

Mechanical Engineering Review,

Vol. 2, No. 1 Feb. 2015, in press.

1

2

21

2

p

p

pp

pp v

Cavitation number :

Injection pressure of the jet : p1

Down stream pressure of nozzle : p2

Vapor pressure : pv

“Cavitation Peening” and “Water Jet Peening”

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 5

337 Nm

376 Nm

418 Nm

12 %

24 %

Improvement of Fatigue Strength of Gear

300

350

400

450

500

Cavitation

Peening

Not Peened

Shot Peening

105 106 107

Torq

ue

Dn

Nm

Number of cycles to failure N

Improvement of fatigue strength of gear demonstrated using

a power circulating type gear tester (Carburized SCM420H)

Joint Project with HONDA H.Soyama and Y.Sekine,

International Journal of

Sustainable Engineering, Vol. 3 (2010), pp. 25-32.

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 6

Improvement of Fatigue Strength of CVT Elements

Improvement of fatigue strength of

elements of steel belt for CVT

Joint Project with TOYOTA

48 %

H.Soyama et al., Journal of Materials

Science, Vol. 43 (2008), pp. 5028-5030.

Cavitation

Peening

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 7

O.Takakuwa and H.Soyama, International Journal of Hydrogen Energy,

Vol. 37, No. 6, (2012), pp. 5268-5276.

Suppression of Hydrogen Embrittlement

Unstable crack growth

Stable crack growth

Not treated

Cavitation Peening

Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku

University 8

Thank you for your kind attentions