11 22 89 9

Journal of Chinese Corrosion Engineering, Vol.14 No.3, PP.11~22(2000)

Development of Duplex Stainless Steel by ACC Process

Horng-Yih Liou*, Yeong-Tsuen Pan**, Rong-Iuan Hsieh**, Wen-Ta Tsai*

2205

900 800 15 /s 80 /s

2205

900

Abstract

The possibility of manufacturing 2205 duplex stainless steel (DSS) by accelerated cooling

control (ACC) process without solution treatment was investigated in this paper. Different initial

cooling temperatures (900 or 800 ) and cooling rates (air, 15 /s or 80 /s) were conducted to

study the variation of microstructure, mechanical property and corrosion resistance of DSS. The

experimental results showed that the specimen treated by high temperature ACC process

possessed similar strength and corrosion resistance as compared to those of the specimen achieved

by traditional solution treatment, however, the toughness is changed in reverse manner.

Keywords: DSS, ACC process, solution treatment

-11-

*

Department of Materials Science and Engineering, National Cheng Kung University

**

Steel and Aluminum Research and Development Department, China Steel Corporation

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89 9

ASTM JIS

1050~1150

(1)

(2)

(TMCP, Thermo-

Mechanical Controlled Processing) TMCP

NKK 1982

(1) 1990

TMCP

304 OL 304 OH 316 OL

316 OH (2,3)

TMCP 2205

(ACC,

Accelerated Cooling Control Process)

2205

160 160mm2 1

1260 1.5

12mm

1100 10

900

800 15 /s 80 /s

ACC

12mm

Charpy

SCC JIS ASTM

40%H2SO

4(60 ) 48

; 6%FeCl3

7 2 ; 3 . 5 w t % N a C l

40wt%CaCl2(100 )

Enp

Epp

;

U 9.4% 40wt%CaCl2(100 )

( + )

50% ( )

<25%

(4,5)

2205

1 2

-13-

(IGA)

/

(2

)2

(700~900 )Type 1 2

2

(6) (650~800 ) Type

2 2 2

K-S(Kurdjumov-Sachs) (7) ( 650 )

Type 3 2 2

(8)

IGA

IGA

Type 3 2

3 900

X XRD

+

XRD

( 4)

(S )

L T

5

YS TS EL

ASTM A240 YS

450MPa TS 620MPa 25%

6 800

(1 /s)

10 /s

TMCP304 (9)

7 Charpy

100J/cm2

900 800

8 900

-20

70 90

(Uppper

shelf energy) (Lower shelf

energy) 0

(separation) 9

-100

Tamura (10)

separation

MnS

{100} (texture)

{100}

texture

texture

separation

(shape control)

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89 9

{100}

(11 13)

10 40wt%

(60 ) 48

3200mpy

4100mpy

( 11)

48

T

SEM/EDS ( 12)

Type 3 2

2

3.1 Type 3 2

Nemoto (14) 5%

Fourie (15) 2205

1M NaCl+1M H2SO

4

20mV Sridhar

Kolts(16) 0.006%N

(0.17%N)

13 6wt%

72

900

1mpy

800

5mpy

5

FeCl3

800

(TTP) (17)

(18 20)

14

3.5wt% NaCl 40wt% CaCl2

100

-15-

Enp

Epp

Cl-

Enp

Epp

3.5wt% NaCl 40wt% CaCl2

3.5wt% NaCl

(14,17) Type 1 2

Type 3 2

2Type 3

15 40wt% CaCl2

(100 ) SCC

290

SCC 430

SCC 200

40wt% CaCl2

(100 ) ( 16)

SCC

SCC 17 900

SCC

(TGSCC)

SCC

TGSCC

SCC

2

(21)

N

Cl- 40wt%

CaCl2(100 )

SCC

SCC SCC

2205

800

900

SCC

1000

1100

2205

1. DSS

2. DSS YS TS

3. DSS

ACC

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89 9

4. 40wt% (60 ) 48 ACC

DSS

2

5. 6wt%FeCl3

72 900

ACC

800

6. 3.5wt%NaCl

40wt%CaCl2(100 )

Cl-

Enp Epp

7. 40wt%CaCl2(100 )

SCC

DSS SCC

DSS SCC

SCC TGSCC

pitting

8. 900

ACC DSS

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K.Hirabe, and K.Yako, Nippon Kokan Technical

Report, Overseas, 35(1982)24.

2. S.Yamamoto, H.Yokoyama, T.Abe, and Y.Kobayashi,

Tetsu-to-Hagane, 79(1993)524.

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4. R.M. Davison and J.D. Redmand, Materials Selection

& Design, Jan., (1990)57.

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Performance of Pipelines, TWI, London, Nov., 1986,

paper 10.

6. B.Josefesson, J.O.Nilsson, A.Wilson, in Proc. Conf.

Duplex Stainless Steel ’91, Beaune, 1, 67, 1991.

7. H.D.Solomon, T.M.Devine. Jr, in Proc. Conf. Duplex

Stainless Steel ’82, St. Louis, ASM, 693, 1982.

8. P.D.Southwick, R.W.K.Honeycombe, Metal Science,

14,7(1980)253.

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Kobayashi, Tstsu-to-Hagane, 79(1993)524.

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"Termomechanical Processing of High-Stength

Low-alloy steels", Butherworth & Co. Publishers,

1998, p.110.

11. T. Tanaka, T. Tabata, N. Hatomure, and C. Chiga, in

Microalloying 75, Union Carbide Corp., 1977,

p.107.

12. M. Fukuda, K. Kunishige, and S. Suguzawa, Tetsu-

to-Hagane, 64(1978)740.

13. T. Mori, T. Enami, T. Funakoshi, and R. Okabe,

ibid, 63(1977)S796.

14. R. Nemoto, K. Osozawa, K. Osada, and M Tsuda, in

"Stainless Steels ’84, 1984, p.149.

15. J.W. Fourie, F.P.A. Robinson, in Proceeding of

International Conference on Stainless Steels, ISIJ,

1991, p.111.

16. N. Sridhar and J. Kolts, Corrosion, 43(1987)646.

17. B. Walden and J.M. Nicholls, Sandvik Steel Report,

S-51-54-ENG, 1, 1994.

18. P. Combrade and J.P. Audouard, in Duplex Stainless

Steels’91, 1(1991)257.

19. H. Hoffmeister, D. Prof, and G. Lothonghum, in

Duplex Stainless Steels’94, 1994, paper 55.

20. H. Miyuki, S. Azuma, K. Ogawa, T. Kudo, and M.

Nishi, The Sumitomo Search, 44(1990)169.

21. 88

1999, p.247.

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1 2205 wt%

Table 1 Chemical composition of 2205 duplex stainless

steel used in this work(wt%)

C Si Mn P S Cr Ni Mo N Fe

0.02 0.5 1.5 0.025 0.004 22.2 5.6 3.1 0.16 Bal.

1 1100

(a) (b)

2 900

(a)87.5 /s,(b)14.3

/s

Fig 1 3 axial microstructure of duplex stainless steel

after (a) air cooling and (b)1100 solution

annealing

Fig 2 3 axial microstructure of duplex stainless steel

after different ACC processes, (a)87.5 /s,(b)

14.3 /s

3.

XRD

Fig 3 XRD analysis of duplex stainless steel after

different ACC processes

1:air cooling, 2:1100 solution annealing, 3:800

ACC (75 /s),

4:900 ACC (87.5 /s), 5:800 ACC (10.7 /s),

6:900 ACC (14.3 )

4

Fig 4 3 axial austenite content of duplex stainless steel

after different ACC processes

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89 9

5

(a)EL (Elongation), (b)YS

(Yield strength), TS (Tensile strength)

Fig 5 Mechanical properties of duplex stainless steel

after different ACC processes, (a)EL, (b)YS, TS

6 (a)

EL, (b)YS, TS

Fig 6 Effect of cooling rate on mechanical property of

duplex stainless steel, (a)EL, (b)YS, TS

7

Fig 7 Absorbed energy of duplex stainless steel after

different ACC processes

8 900

Fig 8 Effect of temperature on absorbed energy of

duplex stainless steel after different ACC

processes

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9

0 (a)

(b) (c) =87.5 /s

Fig 9 Impact fracture surface of duplex stainless steel

after (a) air cooling, (b) solution annealing, and

(c) ACC process (cooling rate = 87.5 /s)

10 40wt% (60

) 48

Fig 10 Corrosion rate of duplex stainless steel after

different ACC processes in 40wt% H2SO

4(60

) for 48h

(a)

(b)

(c)

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11

40wt%

Fig 11 Effect of cooling rate and austenite content on

corrosion rate of duplex stainless steel after

different ACC processes in 40wt% H2SO

4(60

) for 48h

12 40wt% (60 ) 48

T SEM EDS

Fig 12 SEM microstructure observation and EDS

analysis of duplex stainless steel (transverse

surface) after immersion test in 40wt% H2SO

4

(60 ) for 48h

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13 6wt%FeCl3

72

Fig 13 Corrosion rate of duplex stainless steel after

different ACC processes in 6wt% FeCl3

solution for 72h

14 1100

3.5wt%NaCl 40wt%CaCl2

Fig 14 Polarization curves of duplex stainless steel

after air cooling and solution annealing in

3.5wt% NaCl and 40wt% CaCl2

(100 )

solution

15 40wt%CaCl2

SCC

Fig 15 Time to failure of duplex stainless steel after

different ACC processes in 40wt% CaCl2

solution

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89 9

16

40wt%CaCl2(100 )

Fig 16 Effect of cooling rate and austenite content on

time to failure of duplex stainless steel after

different ACC processes in 40wt% CaCl2

solution (100 )

17 900 (14.3 /s)

40wt%CaCl2(100 ) SCC

Fig 17 SCC fracture surface of duplex stainless steel after 14.3 /s ACC

process in 40wt% CaCl2solution (100 )