2019⵳ⶥ㬳∕⩥忧ḙ
March 6th 2020

Research Summaryԭ ඛਸ (Huang Yen-Jui)
Rokkasho Fusion Institute, QST
Institute of Advanced Energy, Kyoto University

1Outline
1. MC research, NTHU (2010 Feb. – 2012 Aug.)
2. RA research, NTHU (2013 Sept. – 2015 Jan.)
3. DC and Postdoc research, KU (2015 Apr. – 2018 Mar./ 2018 Oct. – Present)
4. Future Prospective toward Fusion Energy Research2

MC and RA Research, NTHU

3

MC & RA Research
MS research
Objectives:
Evaluate the efficacy of ZrO2 inhibitive protective
coating (IPC) on 304SS-Alloy82 welds underoxygenated hot water via CBB method
304 SS- A82 safe end weld in BWR recirculating piping system
Results:
1.Crack sites match high hardness and residual
stress; some were arrested or shifted as crack
advancing to fusion boundary
2.Uneven coating promotes localized corrosion
RA research
Objectives:
Elucidate incipient oxidation mechanism of In617
7and Haynes 230, candidate steels for HTGR,
under open air condition
Results:
The oxide ridge above grain boundary of Haynes
230 is less obvious than In617, showing a betteroxidation resistance

In617

A230

4Surface morphology of In617 and Haynes 230 oxidized at 1000oC, 360hr, open air

DC and Postdoc Research , KU

5

Background: SCC history
Backgrounds:
Current austenitic stainless steels and Ni-based alloys used in nuclear power plants suffer SCC
under oxygen- (and) hydrogen-dissolved hot and pressurized water. Further, solution-annealed(SA) 316L showed SCC in hydrogenated water, and fracture surface resembles hydrogen
embrittlement (HE).
Objective:
Access SCC on SA-316L ((and other steels)) under different water chemistries.

6Brief
Bi f hihistory
toff SCC andd major
j ffactors
t occurredd iin LWR
LWRsExperimental
Specimen design and testing loops:

Materials:wt%

FeCr

NiCMoMn

Si304

bal.

18.14 8.06

0.06

-0.79

0.48 0.008 0.033

304L

bal.

18.43 9.71

0.03

-0.99

0.59 0.002 0.031

316L

bal.

17.41

0.022 2.18

10.72 0.004 0.027

310S

bal.

24.76 19.17 0.02

0.8

0.7

12

S

P

0.022

Flowchart: *310S: a low carbon grade, high Ni content ASS
304(L),316L,310S
SA:1050oC,1h,W.Q.
SEN:700oC,100h,W.Q.@316L,310S

650oC,124h,W.Q.@304(L)polishing/grinding

SCWR loop

HW Loop
Parameter

HW loopSCWR loop

Temperature ( C)

25-288288-500

Pressure (MPa)

7.8-8

15.5 – 25

Flow Rate (L/h)

0.75-2

1.4 - 1.6o

#1200-#4000 3 μm -0.25μm

SSRT in HW, PW, SCW waterσ-ε curve, SEM, EBSD

Cond. (uS/cm)<0.1-1

5x10-7

Strain rate (s )Water condition (ppm)*Heat treatment:
SA: Solution-Annealing
SEN: Sensitization

DO-

10,8,4,1,0.2

DH

0.1,0.4,1.4

0.4,1.4

Deaerated

DO,DH < 0.17

Experimental Conditions

3. SCC susceptibility
between SUS316L/SUS310S
4.Sensitization effect
2.SCC in DH condition
1.SCC in DO condition

5. SCC susceptibility
dependence on DH /Temperature

8

1.SCC in DO condition
1. SCC in DO (10ppm) condition- Low carbon (304 -> 304L)- Add Mo (304L->316L)- SA heat treatment (SEN->SA)Can decrease SCC susceptibility

SCC susceptibility decreases
Material

304.SEN

304L.SEN

304L.SA

316L.SA

316L.SEN

10099000

Side
Surface

Fracture
Surface
IG+TG[%]

92.SCC in DH condition
SUS316L-SA

2. SCC in DH (0.1ppm) condition- Fracture: IG initiation-TG propagation- dissolved H2 shifts SCC mechanism

304L.SA DH0.1ppm

Material

304.SA

304L.SA

316L.SA

99

98

32

SideSurface

Fracture
Surface
IG+TG[%]

103. SCC susceptibility between SUS316L/SUS310S
3. SA-310S in HW and PW at DH=1.4ppm- Ni effect: increase Ni content
could decrease SCC susceptibility

316L.SA Deaerated

SSRT in HW

316L.SA DH 1.4ppm
316L.SA DH 1.4ppm PW(340oC)

166 μm
250 μm

310S.SA Deaerated

310S.SA DH 1.4ppm

50 μm

310S.SA DH 1.4ppm PW(340oC)

166 μm200 μm22 μm

114. Sensitization effectConfidential
4. SEN-304 at DH=1.4ppm- SCC susceptibility in DH condition is smaller than in DO.
- Carbide could traps hydrogen, hence less hydrogen being trapped at dislocations
304.SEN DO 8ppm

304.SEN Deaerated

304.SEN DH 1.4ppm

SASEN

Summary of mechanicalproperties of SA andSEN 304 tested inoxygenated, deaerated
and hydrogenated HW

125. SCC susceptibility dependence on DH / Temperature
̶ SCC Mapping
5. SA-316L in HW (RT-288oC) with various DH content
288oC.Deaerated

288oC.DH=0.4

288oC.DH=1.4

IG+TG[%]

324132

Condition

150oC.DH=0.4

220oC.DH=0.4

25oC.DH=1.4

220oC.DH=1.400022Condition

SideSurface

Fracture
Surface

SideSurface

Fracture
Surface
IG+TG[%]

13

5. SCC susceptibility dependence on DH / Temperature̶ Fracture mode
5. SA-316L in HW (RT-288oC) with various DH content- 288oC,DH 0.4ppm, IG initiation- 288oC,DH 1.4ppm, IG initiation – TG propagation- 220oC,DH 1.4ppm, pure TG

14

5. SCC susceptibility dependence on DH / Temperature
5. SA-316L in PW (288-340oC) /SCW (500oC), DH condition
500oC.De.

500oC.DH0.4

500oC.DH1.4

IG+TG[%]

000Condition

288oC.De

340oC.De

288oC.DH1.4

340oC.DH1.40252336Condition

SideSurface

Fracture
Surface

SideSurface

Fracture
Surface
IG+TG[%]

1515

HE behavior in Fe-Cr-Ni alloys
5. Hydrogen Embrittlement:- Two major factors: H2 diffusivity and H2-trapping ability of dislocations
To decrease ‫ܥ‬ு஽௜௦௟௢௖௔௧௜௢௡ :ʀH2 Diffusivity

ʀH2 trapping amountʀHE index

Hydrogentrapped atdislocation

Temp. dependence

Fe-based Alloy

Ni content dependence
316L

by K. Yokogawa
by G.R. Caskey

310S

by G.R. Caskey

16

Summary
Summary- Different water chemistries, heat-treated steels determines different SCC mechanisms- Hydrogen effect depend on both hydrogen concentration and temperature- No SCC found at 500oC (too high to form H2 atmosphere )- Presence of carbide, and increment of Ni could decrease SCC susceptibility

HE

Fracture mode:
Pure IG
IG-TGPure TGDuctile

17

Future Prospective
Publications:- D. Morrall, Y.-J. Huang, K. Yabuuchi, A. Kimura, T. Ishizaki, Y. Maruno, “Corrosion Behavior of Mechanically
Alloyed SUS304L with Zirconium Addition in High-Temperature Water”, Int. J. Metall. Met. Phys. 3:026- Y.-J. Huang, T. Yamaguchi, H. Murai, H. Sugino, T. Nakajima, M. Nono, K. Kawakita, A. Kimura, “SCCsusceptibility of solution-annealed 316L SS in hydrogenated hot water below 288 ˅C”, Corros. Sci. 145 (2018) 1-9- Y.-J. Huang, A. Kimura, “Stress corrosion cracking behavior of 316L and 310S stainless steels in fusion relevantenvironments”, Mater. Trans. 59 (2018) 1267-1274- Y.-J. Huang, K. Kawakita, A. Kimura, “Stress corrosion cracking susceptibility of 310S stainless steel inhydrogenated hot water”, NME 15 (2018) 103-109- E. Hasenhuetl, R. Kasada, Z. Zhang, K. Yabuuchi, Y.-J. Huang, A. Kimura, “Evaluation of Ion-Irradiation
Hardening of Tungsten Single Crystals by Nanoindentation Technique Considering Material Pile-Up Effect,” Mater.
Trans. 58 (2017) 749-756

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Acknowledgements
Supporters from NTHU:- Prof. Tsung-Kuang Yeh, Prof. Jia-Horng Huang, Prof. Ge-Ping Yu, Dr. Mei-Ya Wang,Dr. Kuan-Che Lan, Dr. An-ni Wang
Supporters from KU:- Emeritus Prof. Akihiko Kimura, Assoc. Prof. Kiyohiro Yabuuchi,- master students: Takahiro Yamaguchi, Hirotoshi Murai, Hiroki Sugino,
Tetsuya Nakajima, Masahiro Nono, Kousuke Kawakita, Kiyohiro Yabuuchi,- colleagues: Peng Song, Gin Gao, Zhe-xian Zhang, Daniel Morrall, Eva Hasenhuetl- secretary Ms. Wada, Ms. Ishii- Mr. Hayashi (ADMIRE), Mr. Omura, Mr. Hashitoyo (DuET)

Thank you for your attention19