Effect of an oxygen atmosphere on cyclic hardening in type 316 stainless steel

1970 ◽  
Vol 1 (7) ◽  
pp. 2007-2009 ◽  
Author(s):  
H. H. Smith ◽  
P. Shahinian
Keyword(s):  
Stainless Steel ◽  
Cyclic Hardening ◽  
Oxygen Atmosphere ◽  
316 Stainless Steel

Long-Life Fatigue of Type 316 Stainless Steel at Temperatures up to 593°C

1982 ◽  
Vol 104 (2) ◽  
pp. 137-144 ◽  
Author(s):  
C. E. Jaske ◽  
N. D. Frey
Keyword(s):  
Stainless Steel ◽  
Fatigue Resistance ◽  
Cyclic Hardening ◽  
Design Guidelines ◽  
Austenitic Steels ◽  
Major Advance ◽  
316 Stainless Steel ◽  
Long Life ◽  
The Impact ◽  
Cycles To Failure

Some energy-system structural components may be subjected to 107 or more cycles of small-amplitude, strain-controlled vibrations. In such cases, information on the elevated-temperature, long-life (>106 cycles to failure) fatigue resistance of the austenitic steels often used in these components is needed. Present design guidelines provide fatigue curves for these steels only up to 106 cycles to failure. The objective of the present study was to evaluate the long-life fatigue resistance of one such steel, namely Type 316 stainless steel. Strain-controlled long-life (> 106 cycles to failure) fatigue experiments were conducted on solution-annealed Type 316 stainless steel in air at temperatures from 21 to 593° C. These were all for continuous cycling of smooth specimens under fully reversed straining (no mean stress). Results of this work provided a major advance in understanding the fatigue behavior of this steel. Tentative best-fit fatigue curves have been developed, but more data are needed to establish needed statistical confidence in them. At 21°C, strain and load-controlled experiments gave similar fatigue-resistance values at 108 cycles when inelastic straining was taken into account. However, at 427°C and above, strain-controlled cycling yielded fatigue-resistance levels at 108 cycles about 15 to 25 percent above those for load-controlled cycling. This difference is related to the continually increasing stress levels observed under strain cycling at the higher temperatures. That is, cyclic hardening continues to occur for 105 or more cycles of straining with accompanying two- to threefold increases in strength. This increased strength gives the increased fatigue resistance at long lives. Under load-controlled conditions, such cyclic hardening cannot occur, and the fatigue resistance is lower. Results of this work emphasize the need for considering the intended service conditions in carrying out laboratory experiments. The impact of these results on recommended experimental procedures for long-life fatigue testing of such alloys is discussed. Finally, considerations for application of these data in fatigue design are addressed.

Temperature-Dependence of Multiaxial Non-Proportional Cyclic Behavior of Type 316 Stainless Steel

1989 ◽  
Vol 111 (1) ◽  
pp. 32-39 ◽  
Author(s):  
S. Murakami ◽  
M. Kawai ◽  
K. Aoki ◽  
Y. Ohmi
Keyword(s):  
Stainless Steel ◽  
Temperature Dependence ◽  
Uniaxial Tension ◽  
Constant Strain Rate ◽  
Inelastic Strain ◽  
Cyclic Hardening ◽  
Material Behavior ◽  
Cyclic Behavior ◽  
316 Stainless Steel ◽  
Strain Paths

Temperature dependence of multiaxial cyclic behavior of type 316 stainless steel was elucidated experimentally. Cyclic tests under constant total-strain amplitudes were performed for uniaxial tension-compression and circular (non-proportional) strain paths at several temperatures; room temperature, 200°C, 400°C, 500°C, 600°C, and 700°C. The strain amplitudes of the cycles were specified to be 0.2, 0.3, and 0.4 percent under constant strain rate of 0.2 percent per min. A quantitative discussion was made with special emphasis on the difference between material behavior under uniaxial tension-compression strain cycles and multiaxial non-proportional circular ones at these temperatures. The most significant cyclic hardening was observed in the temperature range between 400°C and 600°C for both the proportional and the non-proportional strain cycles. At these particular temperatures, much larger inelastic strain was accumulated until a cyclic stabilization was obtained. Though the effect of non-proportionality in the cyclic strain paths on the cyclic hardening was significant particularly at the temperature below 450°C, it rapdily decreased at higher temperatures.

Inelastic Behavior of Type 316 Stainless Steel Under Multiaxial Nonproportional Cyclic Stressings at Elevated Temperature

1985 ◽  
Vol 107 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Y. Ohashi ◽  
M. Kawai ◽  
T. Kaito
Keyword(s):  
Stainless Steel ◽  
Cyclic Hardening ◽  
Uniaxial Stress ◽  
Cyclic Stress ◽  
Torsional Stress ◽  
Inelastic Behavior ◽  
Stress Range ◽  
Cyclic Tests ◽  
316 Stainless Steel ◽  
Stress Plane

The stress-range and path-shape dependencies of multiaxial nonproportional cyclic hardening were studied for annealed type 316 stainless steel at 600°C by means of stress controlled tests. Cyclic experiments along circular stress paths with constant effective stresses in the axial-torsional stress plane were first performed. The significant cyclic hardening and its stress-range dependency observed for the circular stress cyclings were quantitatively shown in reference to the cyclic stress-strain curves resulted from uniaxial stress cyclings. Then, to discuss the effect of path-shape, the cyclic tests along square stress paths inscribed by the above circular paths, as well as the tests where uniaxial cyclings and torsional ones were alternated, were also carried out. As a result of these tests, the cyclic hardenings for square paths were found to be almost equivalent to those for their circumscribed circular paths. The other type of stress cyclings caused almost the same amount of cyclic hardenings as those for the circular cyclings of the identical stress-ranges.

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