Thermal Stability

HAYNES® 556® exhibits reasonable retained ductility after long term thermal exposure at intermediate temperatures. It does not exhibit significant sigma phase formation even after 16,000 hours exposure at 1000 to 1600°F(540 to 870°C). Principal phases precipitated from solid solution are carbides and carbonitrides.

Room-Temperature Tensile Properties of Bar Following Thermal Exposure*

Test
Temperature
- 0.2% Offset
Yield Strength
Ultimate Tensile
Strength
Elongation
°F °C h ksi MPa ksi MPa %
1200 650 0 62.5 430 113.4 780 46.5
1000 59.7 410 120.5 830 36.0
4000 57.4 395 121.2 835 33.0
8000 59.8 410 127.3 880 29.4
1400 760 0 62.5 430 113.4 780 46.5
1000 60.8 420 128.7 885 24.8
4000 57.4 395 127.1 875 25.8
8000 54.6 375 125.1 865 24.7
1600 870 0 62.5 430 113.4 780 46.5
1000 52.3 360 112.9 780 32.8
4000 42.8 295 111.5 770 29.0
8000 43.9 305 108.1 745 29.5

*Average of three tests for each condition

Elevated-Temperature Tensile Properties of
Bar Following 16,000-Hour Thermal Exposures*

Test
Temperature
0.2% Offset
Yield Strength
Ultimate Tensile
Strength
Elongation
°F °C ksi MPa ksi MPa %
1000 537 37.4 260 95.7 660 48.0
1200 648 37.8 260 88.8 610 23.4
1400 760 35.1 240 72.3 500 25.3
1600 871 21.9 150 42.1 290 29.5

Room-Temperature Tensile Properties of
Sheet Following 1000-Hour Thermal Exposures*

Exposure Temperature Ultimate Tensile Strength 0.2% Yield Strength Elongation
°F °C ksi MPa ksi MPa %
None None 118.1 815 59.5 410 47.7
1200 648 118.4 815 53.4 370 37.9
1400 760 118.8 820 53.8 370 17.0
1600 871 111 765 46.6 320 20.4
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