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Heat-Resistant Austenitic Stainless Steel

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STAINLESS

Heat-Resistant Austenitic Stainless Steel

（ASTM：UNS 31060）（NSSMC-NAR-AH-4）

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Alloy Design・Features Main Use Applications

Specification andPhysical Properties

Equivalent Specification●ASTM A240, A213　●UNS S31060●ASME Code Case 2430 （ASME Section Ⅰ & Ⅷ, Div.1 Boiler and Pressure Vessel）

Table 1 : Chemical Composition (wt％)

Table 2 : Density, Specific Heat, Thermal Conductivity and Thermal Diffusivity

Table 4 : Poisson' s ratio

Table 3 : Linear Expansion Coefficient

Designation C Si Mn P S Cr Ni N other elements

NSSMC-NAR-AH-4 0.05〜0.10 ≦1.00 ≦1.00 ≦0.040 ≦0.030 22.00〜

24.0010.00〜12.00

0.18〜0.25

La＋Ce0.03〜0.07

UNS S31060 0.05〜0.10 ≦0.50 ≦1.00 ≦0.040 ≦0.030 22.00〜

24.010.00〜

12.50.18〜0.25

La＋Ce0.025〜0.070

B0.001〜0.010

（for reference）SUS 310S ≦0.08 ≦1.50 ≦2.00 ≦0.045 ≦0.030 22.00〜

26.0019.00〜22.00 ─ ─

Designation Density（g/cm3） Specific Heat（J/Kg・K）Thermal Conductivity（W/m・K）Thermal Diffusivity（cm2/sec）NSSMC-NAR-AH-4

UNS S31060 7.88 502 13.8 0.036（for reference）

SUS 310S 8.03 502 14.2 ─

Temperature（℃） 30-100 30-200 30-300 30-400 30-500 30-600 30-700 30-800 30-900 30-1000

Linear Expansion（×10−6/℃） 15.7 16.2 16.8 17.1 17.4 17.7 18.1 18.5 18.7 19.1

WeldabilityCreep RuptureStrength

MicrostructuralStability・Cost Saving

Oxidation Resistance・Erosion Resisitance

High Cr≧22.5% Solid solution strengthening：Addition of N

Grain boundary strengthening：Addition of B

0.3%Si -0.07%C -23%Cr -11%Ni -0.2%N -La+Ce -B

Addition of rareearth metals

Addition of N Decrease of Si

Optimization ofCreq / Nieq

Grain size control

❶ Alloy design of NSSMC-NAR-AH-4

❶ Specification

❷ Physical Properties

1 Parts requiring heat resistance in Industrial Furnaces, Heat-treating Furnaces, Power Plants and Chemical Plants.

2 Fuel cell reforming Tube. 3 Auto parts （Exhaust Manifold etc.）. 4 Substitute for SUS310S. Especially suited for material requiring high-temperature mechanical strength.

Temperature（℃） RT 450 500 600 700 800 900 1000

Modulus of Elasticity（GPa） 188 158 154 146 138 130 128 119

Poisson' s ratio 0.260 0.260 0.260 0.262 0.263 0.263 ─ ─

●Lower sensitivity of weld hot cracking than SUS310S, especially favorable for thick plates welding.

❸ Superior Weldability

●Reasonably designed chemical composition as compared with SUS310S.

❹ Cost Saving

●Higher tensile strength and creep strength at high temperature than SUS310S （JIS G4303）.

●Excellent oxidation resistance at 900〜1000℃ superior to SUS310S.

●Superior structure stability after long-term exposure to high temperature （700〜900℃）,　 without a drastic drop in toughness like SUS310S.

❷ Superior High Temperature Properties

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❸ Mechanical Properties

Table 5 : Mechanical Properties

Table 6 : Typical Chemical Composition (wt%)

Designation 0.2% Yield Strength（N/mm2） Tensile Strength（N/mm2） Elongation（％） Hardness（HRB）NSSMC-NAR-AH-4

UNS S31060 ≧280 ≧600 ≧40 ≦95（for reference）

SUS 310S ≧205 ≧520 ≧40 ≦90

Designation C Si Mn P S Cr Ni N La＋Ce B

NSSMC-NAR-AH-4 0.07 0.31 0.48 0.021 0.001 23.11 10.95 0.197 0.03 0.003（for reference）

SUS 310S 0.05 0.58 1.21 0.023 0.001 24.63 20.25 0.024 ─ ─

Properties of NSSMC-NAR-AH-4

❶ Chemical Composition

❷ Microstructure

● Austenitic structure● Grain size：Average grain size of ASTM No.7 or coarser, as measured by Test Methods E112 （ Thickness ≧ 6mm）

Photo 1. Typical microstructure after solution heat treated

❸ High-temperature Properties

Fig.1 Tensile properties at high temperature

Fig.3 Creep rupture properties

Fig.5 Cyclic oxidation test result in the air Fig.6 Continuous oxidation test result （200h）

Fig.2 Tensile properties at room temperature

Fig.4 Charpy impact properties after aged at 700～900℃

300

200

100

800 900 10000

： AH-4： SUS 310S

Tensile Strength

0.2% Yield Strength

Test Temperature （℃）

0.2% Yield Strength/Tensile Strength

（N/mm2 ）

900

800

700

600

500

400

300

200

0AH-4 SUS 310S

0.2% Y.S.T.S.

0.2% Yield Strength/Tensile Strength

（N/mm2 ）

102 103 104 105

50

30

10

5

Stress

（N/mm2 ）

Time to rupture （h）

Designation900℃1000℃

SUS 310SAH-4

600 800 1000Aging temperature （℃）

150

100

50

0

AH-4

SUS 310SImpact Value

（J/cm

2 ）

Test piece：2mm V-notch, half sizeTest temperature：room temperatureAging time：3000h

❹ Resistance to high-temperature oxidation

-100

0

-100

0

0 100 200 300cycles

SUS 310S900℃

AH-4

400

（25minutes heating-5minutes air cooling）

Weight change by oxidation

（g/m2 ）

SUS 310S1000℃

AH-4

40

30

20

10

0AH-4 SUS 310S

900℃1000℃ in air

Weight gain by oxidation

（g/m2 ）

5 6

❺ Resistance to high-temperature erosion ❻ Weldability

Fig.7 Erosion test result （900℃） Fig.8 Hot cracking test result（Longi Varestraint test）

Weight loss

（mg）

Maximum depth of thickness loss

（μm）

Time （h）

600

400

50 100

200

0

4000

2000

3000

1000

0

SUS 310S

DesignationWeight loss Maximum depth ofthickness loss

AH-4

Blasted speed：5m/sTemp.：900℃Abrasives：silicate sand

AH-4 SUS 310S

Total crack length

（mm）

10

5

0

No crack

（n＝2）ε＝2%

↓

❼ Creep Rupture Strength of Welded Joint

❽ Welding Consumables

102 103 104 105

50

30

10

5

Stress

（N/mm2 ）

Time to rupture （h）Base metal thickness：20mmWelding process：GTAWWelding consumable：WEL Auto TIG AH-4（1.2φ）

AH-4900℃ 1000℃Base MetalWelded Joint

●Supplier : Nippon Welding Rod Co., Ltd.[URL] http://www.nihonwel.co.jp/[e-mail] info@nihonwel.co.jp

For TIG welding

WEL TIG AH-4 1.2, 1.6, 2.0, 2.4, 3.2mmφWEL Auto TIG AH-4 1.2, 1.6mmφ

For SMA welding

WEL AH-4 2.6, 3.2, 4.0, 5.0mmφ

Available Sizes

Thickness

（mm）

Width （mm）

Available maximum length：6,000mm

Consult us for custom-made dimensions.：Range of consultation

1,000

0.1

0.3

3.06.0

32.0

40.0

600

1000 1219

15242000

2,000 3,000

（Cold rolling）

（Hot rolling）

Fig.9 Creep rupture testresult of welded joint