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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