Mechanical properties of all-weld metal (3)

Chemical composition of all-weld metal㧔%㧕(1) (2) Class. C 0.12 0.12

E409Nb E410 E410NiMo E430 E430Nb E630 E16-8-2

0.06 0.10 0.10 0.05 0.10

Cr

Ni

Mo

Nb(Cb) +Ta

Mn

Si

0.50-1.50 1.0 1.00 11.0-14.0 0.6 0.75 1.0 0.90 11.0-13.5 0.7 0.75 1.0 0.90 11.0-12.5 4.0-5.0 0.40-0.70 1.0 0.90 15.0-18.0 0.6 0.75 0.50-1.50 1.0 1.00 15.0-18.0 0.6 0.75 16.00-16.75 4.5-5.0 0.75 0.15-0.30 0.25-0.75 0.75 14.5-16.5 7.5-9.5 1.0-2.0 0.5-2.5 0.60

P 0.04 0.04 0.04 0.04 0.04 0.04 0.03

S

Cu

0.03 0.75 0.03 0.75 0.03 0.75 0.03 0.75 0.03 0.75 0.03 3.25-4.00 0.03 0.75

Class.

E2209

0.04

E2553

0.06

E2593

0.04

Nb(Cb) +Ta

Cr

Ni

Mo

21.523.5 24.027.0 24.027.0 24.027.0 24.027.0

8.510.5 6.58.5 8.510.5 8.510.5 8.510.5

2.53.5 2.93.9 2.93.9 3.54.5 2.54.5

-

-

-

-

Mn 0.52.0 0.51.5 0.51.5 0.52.0

Si

P

S

0.90

0.04

0.03

1.0

0.04

0.03

1.00

0.04

0.03

1.00

0.04

0.03

2.5

1.2

0.03

0.025

El., Min. (%)

PWHT

65 65 110 65 65 135 80

20 20 15 20 20 7 35

d a c d d e None

Classification suffix

Type of current

Welding position

-15

DC-EP

All

-16

DC-EP and AC

All

-17

DC-EP and AC

All

-26

DC-EP and AC

H, F

Mechanical properties of all-weld metal (3)

Chemical composition of all-weld metal㧔%㧕(1) (2)

C

TS, Min (ksi)

ԙ: Type of current and welding position

N 0.080.20 0.100.25 0.080.25 0.200.30 0.200.30

E2594

0.04

E2595

0.04

E3155

0.10

20.022.5

19.021.0

2.53.5

0.751.25

1.02.5

1.00

0.04

0.03

-

E33-31

0.03

31.035.0

30.032.0

1.02.0

-

2.54.0

0.9

0.02

0.01

0.30.5

Cu

TS, Min (ksi)

El., Min. (%)

PWHT

-

100

20

None

-

110

15

None

-

110

15

None

-

110

15

None

110

15

None

100

20

None

105

25

None

Others

0.75 1.52.5 1.53.0 0.75 0.41.5

W: 0.4-1.0 Co: 18.5-21.0 0.75 W: 2.0-3.0 0.40.8

Note: (1) Single values are maximum. (2) The total of other elements, except iron, shall not present in excess of 0.5%. (3) All-weld-metal mechanical properties are obtained after the following PWHT: a: Heat to 1350 to 1400°F (730 to 760°C), hold for one hour, furnace cool at a rate of 100°F (55°C) per hour to 600°F (315°C) and air cool to ambient. b: Heat to 1550 to 1600°F (840 to 870°C), hold for two hours, furnace cool at a rate not exceeding 100°F (55°C) per hour to 1100°F (595°C) and air cool to ambient. c: Heat to 1100 to 1150°F (595 to 620°C), hold for one hour, and air cool to ambient. d: Heat to 1400 to 1450°F (760 to 790°C), hold for two hours, furnace cool at a rate not exceeding 100°F (55°C) per hour to 1100°F (595°C) and air cool to ambient. e: Heat to 1875 to 1925°F (1025 to 1050°C), hold for one hour, and air cool to ambient, and then precipitation harden at 1135 to 1165°F (610 to 630°C), hold for four hours, and air cool to ambient.

372

373

KOBELCO WELDING TODAY

PRODUCTS SPOTLIGHT

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GPS 4VQFS
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4UFFMT NC-2594 (AWS E2594-16) DW-2594 (AWS E2594T-1/4) TG-S2594 (AWS ER2594)

D

uplex stainless steel has a microstructure consisting virtually of 50% austenitic phase and 50% ferritic phase, and thus possess excellent ductility, notch toughness and resistance to stress corrosion cracking (SCC). Duplex stainless steel also offers higher tensile strength than normal singlephase stainless steels. The advantages obtained by combining the two phases enable this stainless steel to be applied in corrosive environments, like seawater, which contains the chloride ion (Cl). Such applications exist in chemical plants, drill pipes for crude oil and natural gas, line pipes, chemical tankers, and water gates. The corrosion resistance of duplex stainless steel is determined through the Pitting Resistance Equivalent (PRE), which is calculated as: PRE = Cr + 3.3Mo + 16N. Applications in extremely corrosive environments require the materials to have superior corrosion resistance as indicated by a higher PRE. When the PRE is required to be 40 or higher, super duplex stainless steel and a matching filler metal are the correct choices. PREMIARCTM NC-2594, DW-2594, and TG-S2594 are sophisticated filler metals developed for 25Cr-type duplex stainless steels (Table 1), especially for the super duplex grades (S32750, S32760). These filler metals are also suitable for 22Cr-type duplex stainless steels such as ASTM (UNS) S31803 and S32205. The typical chemical composition and mechanical properties of the filler metals are shown in Tables 2 and 3, respectively. Table 1: Typical 25Cr-type duplex stainless steels ASTM (UNS) S32750

1.4410

S32760

1.4501

S32506

-

EN

JIS

Table 3: Typical mechanical properties of NC-2594, DW-2594 and TG-S2594 all weld metals Trade desig. NC-2594 DW-2594*1 TG-S2594

0.2% PS (MPa) 750 712 721

TS (MPa) 935 905 870

El (%) 28 27 31

IV at –40°C (J) av. 40 av. 39 av. 270

IV at –20°C (J) av. 50 av. 48 av. 291

*1: With an 80%Ar-20%CO2 shielding gas.

As shown in Table 4, NC-2594, DW-2594 and TG-S2594 exhibit excellent pitting corrosion resistance. Table 4: Typical pitting corrosion test results of NC-2594, DW2594 and TG-S2594 all weld metals Trade desig. NC-2594 DW-2594*1 TG-S2594*2

Size of specimen

Test solution

Time of exposure

3 x 20 x 30 mm

6%FeCl3 + 1%HCl solution aq.

24 hours

CPT *3 (°C) 40 40 50

*1: With an 80%Ar-20%CO2 shielding gas. *2: With a 98%Ar-2%N2 shielding gas *3: Critical pitting temperature, determined by ASTM G48 Practice E.

Through butt joint tests using 25Cr-type duplex stainless steels, these filler metals have been proven sufficient in relation to bead appearance, radiographic soundness, macroand micro-structure, side bend properties, tensile properties, notch toughness, hardness, and ferrite content. Figure 1 shows an example of the test results of DW-2594.

Chemical composition

-

25Cr-7Ni-4Mo-0.28N 25Cr-7Ni-3.8Mo-0.7Cu0.7W-0.25N SUS329J4L 25Cr-7Ni-3Mo-0.15N-0.2W -

Table 2: Typical chemical composition, PRE and FNW of NC2594 and DW-2594 all weld metal and TG-S2594 filler wire NC-2594 Trade desig. for SMAW AWS A5.4 E2594-16 C% 0.04 0.035 Si% 1.00 0.55 Mn% 0.5-2.0 0.66 P% 0.04 0.017 S% 0.03 0.001 Cu% 0.75 0.04 Ni% 8.0-10.5 9.82 Cr% 24.0-27.0 26.61 Mo% 3.5-4.5 3.86 Nb% 0.016 W% N% 0.20-0.30 0.25 PRE 43.4 FNW*2 50

DW-2594 TG-S2594 for FCAW*1 for GTAW A5.22 E2594T1-1/4 A5.9 ER2594 0.04 0.026 0.03 0.019 1.00 0.50 1.0 0.44 0.5-2.5 1.18 2.5 0.57 0.04 0.02 0.03 0.018 0.03 0.005 0.02 0.0003 1.5 0.031 1.5 0.10 8.0-10.5 9.6 8.0-10.5 9.30 24.0-27.0 25.7 24.0-27.0 24.96 2.5-4.5 3.79 2.5-4.5 3.82 0.016 0.02 1.0 <0.1 1.0 0.01 0.20-0.30 0.24 0.20-0.30 0.28 42.0 42.6 49 42

*1: With an 80%Ar-20%CO2 shielding gas. *2: Ferrite Number (FN) as per a WRC-1992 diagram.

1

Vol. 13 No. 2 2010

Figure 1: DW-2594 (1.2 mmø) weld metal exhibits an optimal austenite-ferrite phase (left) and good fusion in the multi-pass weld (right)  20-mm thick S32760 base metal, horizontal position, 80%Ar-20%CO2.

These filler metals are suitable for all position welding with DCEP current for NC-2594 and DW-2594, and DCEN for TG-S2594. An 80%Ar-20%CO2 shielding gas is recommended for DW-2594, although a 100%CO2 shielding gas can also be used. Heat input should be controlled in a range of 5-25 kJ/cm to obtain an optimized duplex microstructure with a well-balanced austenite-ferrite phase, thereby ensuring sufficient corrosion resistance and notch toughness of the weld metal and heat-affected zone. No preheat is required. Interpass temperature should be 150°C or lower.