Post on 19-Apr-2018
Fundamental of “Cavitation Peening” is now on YouTube. 3 min. https://youtu.be/BurRGrmOGQY
Invited review paper about “cavitation peening” is available on following URL as OPEN ACESS Journal. http://www.oldcitypublishing.com/wp-content/uploads/2017/11/IJPSTv1n1p3-60Soyama.pdf
H. Soyama,
“Key Factors and Applications of Cavitation Peening” International Journal of Peening Science and Technology Vol. 1 (2017), pp. 3-60.
Cavitation S Peening® S:Shotless, Shockwave, Smooth, Soyama
is a peening method
using cavitation impacts in the same way as shot peening
to improve fatigue strength and/or to introduce compressive
residual stress. The peening method using cavitation
impact is called “cavitation shotless peening (CSP)”, as
shots are not required (see Fig. 1). In the case of cavitation
shotless peening, cavitation is generated by cavitating jet.
is phase change phenomena from
liquid-phase to gas-phase. It is similar to boiling,
but, in the case of cavitation, liquid-phase becomes
gas-phase by decrease of static pressure until
saturated vapor pressure due to increase of flow
velocity (see Fig. 2). When the static pressure is
increased by decrease of the flow velocity, the
cavitation bubble is collapsed. At the cavitation
bubble collapse, a part of the bubble is deformed
and a micro-jet is produced (see Fig. 3). As the
speed of the micro-jet is about 1,500 m/s, the
micro-jet produces plastic deformation pit on the
solid surface. After the cavitation bubble shrink, the
cavitation bubble rebounds. At the rebound, shock
wave is produced. The shock wave also produces
plastic deformation (see Fig. 3).
is a jet with cavitation bubbles produced by injecting a high-speed water jet into water
(see Fig. 4). The cavitation bubbles take place in the low pressure region of vortex core in the shear layer
around the jet. The vortex cavitations combine and big cavitation cloud is produced. When the cavitation
cloud hit the surface, cavitation impacts are produced at bubble collapses. Soyama successfully produced
cavitating jet in air by injecting a high-speed water jet into a low-speed water jet.
*1 H.Soyama, Trans. ASME, Journal of Fluids Engineering, Vol. 127, No. 4, 2005, pp. 1095-1101. [2015.5.15]
Cavitation S Peening®
Nozzle
Flow
Fig. 1 Shotless peening and shot peening
Cavitation
.2
2
constzgpv
Head Static pressure
Flow velocity
Bernoulli’s equation
Fig. 2 Phase diagram of water and Bernoulli’s equation
Solid surface
Micro-jetShock waveCavitation bubble
Rebound
In Water
Plastic deformation[High speed/Low pressure region] [Low speed/High pressure region]
Fig. 3 Schematic diagram of cavitation bubble
Cavitating jet
Fig. 4 Schematic diagram and photo of cavitating jet
Schematic diagram Cavitating jet in water Cavitating jet in air*1
Shotless Shot
Cavitating Jet
CavitationImpact
― Improvement of Fatigue Strength ― Cavitation S Peening® improves the fatigue strength of gear made of carburized chromium molybdenum steel SCM420H*1. It also enhances the fatigue strength of carburized chromium molybdenum SCM420*2 and SCM415*3, aluminum alloy AC4CH-T6*4, Duralumin, magnesium alloy, stainless steel, silicon manganese steel and other materials.
*1 H.Soyama and Y.Sekine, “Sustainable Surface Modification Using Cavitation Impact for Enhancing Fatigue Strength
Demonstrated by a Power Circulating-Type Gear Tester,” International Journal of Sustainable Engineering, Vol. 3, No. 1, 2010, pp. 25 - 32.
*2 H.Soyama, “Improvement of Fatigue Strength of Metallic Materials by Cavitation Shotless Peening,” Metal Finishing News, Vol. 7, March issue, 2006, pp. 48 - 50.
*3 D.Odhiambo and H.Soyama, “Cavitation Shotless Peening for Improvement of Fatigue Strength of Carbonized Steel,” International Journal of Fatigue, Vol. 25, Nos. 9-11, 2006, pp. 1217 - 1222.
*4 H.Soyama, K.Sasaki, K.Saito and M.Saka, “Cavitation Shotless Peening for Improvement of Fatigue Strength of Metallic Materials,” Transaction of Society of Automotive Engineers of Japan, Vol. 34, No. 1, 2003, pp. 101 - 106.
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University
300
350
400
450
500
Fig. 5 Improvement of fatigue strength of gear demonstrated using a power circulating type gear tester (Carburized SCM420H)*1
105 106 107
Number of cycles to failure N
Torq
ue
Dn
Nm
Not peened
Shot Peening
Cavitation Peening
700
800
900
1000
104
Not peened
SP1
SP2 CSP
Am
plitu
de o
f be
ndin
g st
ress
a
M
Pa
105 106 107 108
Number of cycles to failure N
Fig. 6 S-N curve of rotating bending fatigue test (Carburized SCM420)*2
700
800
900
1000
CSP
SP
Not peened
106 104 107 108 105
Am
plitu
de o
f be
ndin
g st
ress
a
M
Pa
Number of cycles to failure N
Fig. 7 S-N curve of rotating bending fatigue test (Carburized SCM415)*3
80
120
160
200
CSP
SP
Not peened
Am
plitu
de o
f be
ndin
g st
ress
a
M
Pa
Number of cycles to failure N
106 107 108 105
Fig. 8 S-N curve of rotating bending fatigue test (AC4CH-T6)*4
― Peened Surface ― Cavitation S Peening® introduces compressive residual stress with a considerable less surface roughness compared to that from shot peening (see Figs. 9 and 10). Individual pit induced by Cavitation S Peening® does not have sharp tip up around the pit, compared to a pit induced by ball indentation at nearly constant volume and depth (see Fig. 11). It is very shallow compared to the pit at constant depth of plastic deformation area (see Fig. 12).
*5 H.Soyama, D.O.Macodiyo and S.Mall, “Compressive Residual Stress into Titanium Alloy Using Cavitation Shotless Peening Method,” Tribology Letters, Vol. 17, No. 3, 2004, pp. 501 - 504.
*6 H.Soyama, “Introduction of Compressive Residual Stress Using a Cavitating Jet in Air,” Trans. ASME, Journal of Engineering Materials and Technology, Vol. 126, No. 1, 2004, pp. 123 - 128.
*7 H.Soyama, “Distribution of Residual Stress around Plastic Deformation Pit Induced by Cavitation Shotless Peening,” Proceedings of 2005 Annual Meeting of JSME/MMD, 2005, pp. 361 - 362.
*8 A. Kai and H.Soyama, “Visualization of the Plastic Deformation Area beneath the Surface of Carbon Steel Induced by Cavitation Impact,” Scripta Materialia, Vol. 59, No. 3, 2008, pp. 272 - 275.
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University
CSP (Ra = 0.53 m) SP (Ra = 2.44 m) -1200
-800
-400
0
400
0 50 100 150 200
SP
Distance from the surface z m
Res
idua
l str
ess
MP
a
Not peened
CSP
Fig. 9 Peened surface and residual stress (Ti-6Al-4V)*5
-1000
-800
-600
-400
-200
0
200
0 20 40 60 80CSP (Ra = 0.10 m) SP (Ra = 1.01 m) Distance from the surface z m
Res
idua
l str
ess
MP
a
SP
Not peened
CSP
Fig. 10 Peened surface and residual stress (SKD61)*6
400 m
40 m
400 m
400 m
40 m
400 m
(a) CSP (b) Ball indentation
Fig. 11 Aspect of pit*7
35 m 90 %
450 m
Volume 2.3 mm3 32 m
480 m
2.2 mm3 90 %
Fig. 12 Depth and plastic deformation area*8
h' h
― Singularity of CSP ― Full width at half maximum of diffracted X-ray profile from alloy tool steel peened by Cavitation S Peening® becomes narrower than that of not peened specimen (see Fig. 13). The ratio of arc height between N-gage and A-gage of Almen strip peened by Cavitation S Peening® is different from that of shot peening (see Fig. 14).
― Peening Effect ― Cavitation S Peening® can be applied for suppression of cracks induced by heat cycle (see Fig. 15), relief of micro strain (see Fig. 16), peen forming (see Fig. 17), and enhancement of CVT element (see Fig. 18).
*9 H.Soyama, “Macro and Micro Strain in Polycrystalline Metal Controlled by Cavitation Shotless Peening,” Metal Finishing News, Vol. 7, November issue, 2006, pp. 48 - 50.
*10 H.Soyama, H. Kumano, K. Saito and M. Saka, “Evaluation of Peening Intensity of Cavitation Shotless Peening by Using Almen Strip,” Proceedings of APCFS & ATEM '01, 2001, pp. 1047 - 1050.
*11 H.Soyama, “Surface Modification of Metallic Materials by Using String Cavitation,” Journal of Japan Society for Heat Treatment, Vol. 48, No. 2, 2008, pp. 74 - 78.
*12 H.Soyama and N.Yamada, “Relieving Micro-Strain by Introducing Macro-Strain in a Polycrystalline Metal Surface by Cavitation Shotless Peening,” Materials Letters, Vol. 62, No. 20, 2008, pp. 3564 - 3566.
*13 H.Soyama and K. Saito, “Peen Forming Using a Cavitating Jet in Air,” Proceedings of Pacific Rim International Conference on Water Jetting Technology, 2003, pp. 429 - 436.
*14 H.Soyama, M.Shimizu, Y.Hattori and Y.Nagasawa, “Improving the Fatigue Strength of the Elements of a Steel Belt for CVT by Cavitation Shotless Peening,” Journal of Materials Science, Vol. 43, No. 14, 2008, pp. 5028 - 5030.
Intell igent Sensing of Materials Lab. Intell igent Sensing of Materials Lab. Intelligent Sensing of Materials Lab. Intell igent Sensing of Materials Lab. Intell igent Sensing of Materials Lab.
Prof. Hitoshi Soyama, Department of Nanomechanics, Tohoku University 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, JAPAN
0
20
40
102 104 106 108Rel
ativ
e in
tens
ity o
f X
-ray
Diffraction angle 2��
SP
CSP
NP NNNPPP
PPPiii tttsss
CCCSSSPPP
SSSPPP
Fig. 13 Diffracted X-ray profile and peened surface of alloy tool steel SKD61*9
0.00
0.04
0.08
0.12
0 2 4 6 8 10Processing time t s/mm
Mic
ro-s
trai
n
(1 1 0)
(2 0 0)
(2 1 1)
Fig. 16 Relief of micro strain by CSP*12
0.8
1.0
1.2
1.4
1.6
1.8
Not peened
106 104 105 103 Number of cycle to failure N
Nor
mal
ized
ben
ding
fo
rce
F CSP
Fig. 18 S-N curve of CVT elements*14
0
0.2
0.4
0.6
0.8
0 5 10 15Processing time t s/mm
Cur
vatu
re m
-1
Fig. 17 Curvature induced by CSP*13
p1 = 30 MPa
20 MPa
0 200 400 600 800
SB-nitriding + FPB Gas nitridung + SP SB-nitriding + HSP Gas nitriding + HSP SB-nitriding + CSP Gas nitriding + CSP
Fig. 15 Number of cracks after heat cycle test*11 Number of cracks
Fig. 14 Relation on arc height between N-and A-gauge, and surface of Almen strip*10
42.0N
A
dH
dH
33.0N
A
dH
dH
CSP
SP
(c) SP HN =0.15 mm
(b) CSP HN =0.32 mm
(a) Not peened
0.00
0.05
0.10
0.15
0.20
0.00 0.10 0.20 0.30 0.40Arc height H N mm
Arc
hei
ght H
A m
m
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University
Cavitation S Peening® ― Several Types of Cavitating Jets and Water Jet ―
*1 H.Soyama, Trans. ASME, Journal of Engineering Materials and Technology, Vol. 126, No. 1, 2004, pp. 123 - 128. *2 H.Soyama, Trans. ASME, Journal of Fluids Engineering, Vol. 127, No. 4, 2005, pp. 1095- 1101. *3 H.Soyama, Journal of Materials Science, Vol. 42, No. 16, 2007, pp. 6638-6641. *4 H.Soyama et al., ISIJ International, Vol. 48, No. 11, 2008, pp. 1577-1581. *5 H.Soyama et al., Surface & Coatings Technology, Vol. 205, 2011, pp. 3167-3174. *6 H.Soyama and O.Takakuwa, Journal of Fluid Science and Technology, Vol. 6, No. 4, 2011, pp. 510-521.
Cavitating jet in water
Water jet in water
Cavitating jet in air
Water jet with associated water jet in air
Cavitating jet in water with associated water jet
Water jet with associated water jet in water
Cavitating jet in water with pressurized chamber
Water jet with associated water jet in water
Normal water jet
Water jet in air
Fig. 1 Erosion pattern of several types of cavitating jets and a normal water jet *1, *2, *3, *4, *5, *6
At cavitation peening, there is no erosion, as process is finished before erosion takes place.
t = 0 ms
0
20 mm
0.600 msFig. 2 Changing appearance of a cavitating jet in air with time*2
250
300
350
400
Number of cycles to failure N
Am
plitu
de
of b
endi
ng s
tres
s
a M
Pa
Cavitating jet in air
104 105 106 107 108
Not peened
Cavitating jet in water at s = 65mm
Cavitating jet in water at s = 25mm
Fig. 3 S-N curve of SUS316L*3
300
350
400
450
500
104 105 106 107
Am
plitu
de
of b
endi
ng s
tres
s
a M
Pa
Number of cycles to failure N
Not peened
Cavitating jet in water with associated water jet
Fig. 4 S-N curve of grinded SUS316L*4
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University 1
Severe erosive vortex cavitationRing vortex cavitation
Cloud cavitation
Vortex cavitation in shear layer
Impinging surface
Nozzle
High-speedwater jet
Schematic diagram of cavitating jet
High speed photographof cavitating jettaken by Soyama
WATER
How to Produce Cavitation; Cavitating JetH.Soyama,J. Soc. Mater. Sci., Japan,,47 (1998), pp. 381-387.
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University0
0.1
0.2
0.3
0.4
0.5
0.6
0 100 200 300 4002
Developing regionOf vortex cavitation
Collapsing region ofvortex cavitation
Surface
Cloud cavitation
Ring erosion
Vortex cavitation
In Water
Pressurizedwater
DropletsCollapsing region ofvortex cavitationCavitation
impacts
Inve
rse
of c
urva
ture
1/
m-1
Normalized standoff distance s/d
p1 = 300 MPa, d = 0.4 mm
p1 = 30 MPa, d = 2 mm
Dropletsimpacts
Cavitation impacts
Dropletsimpacts Cavitation impacts
(Arc
hei
gh
t)
H.Soyama,Mechanical Engineering Review,Vol. 2, No. 1 Jan. 2015,Paper No. 14-00192, pp. 1-20.
“Cavitation Peening” and “Water Jet Peening”
d
Standoff distance sStandoff distance s
Potential core
p1 = 300 MPa
Ag
gre
ssiv
ity
of
jet
Jet power (= injection pressure x flow rate)is nearly equal.
Droplet and/or shot impacts are used.Cavitation impacts are used
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University 3
≧ 1.8 .
<1.8 .
Cavitation Peening
Water Jet Peening
H.Soyama,
Mechanical Engineering Review,Vol. 2, No. 1 Jan. 2015,Paper No. 14-00192, pp. 1-20.
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”
Ag
gre
ssiv
ity
of
jet
Droplet and/or shot impacts are used.Cavitation impacts are used
Intelligent Sensing of Materials Lab., Department of Nanomechanics, Tohoku University 4
Injection Pressure and Nozzle Size
In order to avoid the damage, the low injection pressure and large nozzle size is better than the high injection pressure for cavitation peening.
Jet power = (Injection pressure) X (Flow rate)
Standoff distance
ppvvpp11
pp22
Peenedsurface
dd
Standoff distance
ppvvpp11
pp22
Peenedsurface
dd
H. Soyama and O. Takakuwa, Journal of Fluid Science and Technology, Vol. 6 (2011), pp. 510-521.
Damage
-300
-200
-100
0
100
0 200 400 600Depth from the surface z m
Res
idu
al s
tres
s
RM
Pa
Not-peened
Compression
Tension
p1 = 300 MPa, d = 0.35 mm
p1 = 30 MPa, d = 2 mm
Jet power is nearly equal.