Creep Deformation of 20 Percent Cold Worked Type 316 Stainless Steel

1977 ◽  
Vol 99 (2) ◽  
pp. 168-180 ◽  
Author(s):  
E. R. Gilbert ◽  
L. D. Blackburn
Keyword(s):  
Stainless Steel ◽  
Creep Strain ◽  
Creep Deformation ◽  
Stress Conditions ◽  
Constant Stress ◽  
Experimental Results ◽  
Temperature Dependent ◽  
316 Stainless Steel ◽  
Stress Levels ◽  
Cold Worked

Creep deformation of internally pressurized tube specimens of 20 percent cold worked Type 316 stainless steel was measured under isothermal, constant stress conditions. Stress levels varied from zero to as high as 413 MPa (60,000 psi) for tests at five temperatures over the range from 714 K (825°F) to 1033 K (1400°F) for times to 3.6 × 106 seconds (2410 hours). Experimental results were represented by an equation of the form εc=Aσcosh−1(1+rt)+Pσntm+Qσnt2.5 where εc is the creep strain, σ is the stress, t is time, and the remaining quantities are temperature dependent parameters.

Microstructure and Post-Irradiation Annealing Behavior of 20% Cold-Worked 316 Stainless Steel

2000 ◽  
Vol 650 ◽  
Author(s):  
J. I. Cole ◽  
T. R. Allen ◽  
H. Kusanagi ◽  
K. Dohi ◽  
J. Ohta
Keyword(s):  
Stainless Steel ◽  
Cold Work ◽  
Microstructural Development ◽  
Dislocation Loops ◽  
Annealing Behavior ◽  
Post Irradiation ◽  
316 Stainless Steel ◽  
Dose Rates ◽  
Cold Worked

ABSTRACTMicrostructural examination and in situ post-irradiation annealing studies were carried out on 20% cold-worked 316 stainless steel (SS) hexagonal duct material following irradiation in the reflector region of the EBR-II reactor. Stainless steel hexagonal ducts were used to house reactor subassemblies and provide a valuable source of information on irradiation behavior of reactor structural materials at lower dose-rates (on the order of 10-8 dpa/sec) than previously examined. The microstructural development of samples irradiated to doses of 1, 20 and 30 dpa is examined, while the post-irradiation annealing behavior of a sample irradiated to 20 dpa is described. Annealing studies were performed at 370 and 500°C to examine the kinetics of radiation damage recovery as a function of annealing temperature. The initial (pre-annealed) microstructures consists of a substantial density of irradiation induced chromium-rich M23C6 and M6C carbides which form both on the grain boundaries and within the grain interiors. Recovery of the cold- work is evident in the 1 dpa sample while samples irradiated to 20 and 30 dpa possess dense populations of voids and dislocation structures consisting of networks of line dislocations and faulted dislocation loops. Results indicate that post-irradiation annealing of the samples at 370°C for 1 hour has little effect on the microstructure, while further annealing at 500°C for 1 hour results in void shrinkage, the formation of small cavities, and a reduction in the dislocation loop and network density.

Development of the RCC-MR Creep Deformation Model for the Prediction of Creep and Stress Relaxation in Type 321 Stainless Steel

2014 ◽  
Author(s):  
A. J. Moffat ◽  
J. P. Douglas ◽  
M. White ◽  
M. W. Spindler ◽  
C. Austin ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stress Relaxation ◽  
Creep Strain ◽  
Creep Deformation ◽  
Constant Load ◽  
Fatigue Tests ◽  
Creep Model ◽  
Deformation Model ◽  
Relaxation Data ◽  
Creep And Stress Relaxation

In this paper a creep deformation model has been developed for Type 321 stainless steel which has been based on a modified version of the creep model that is used in the French fast reactor design code RCC-MR. The model has been evaluated using: 1) constant load creep data covering the temperature range from 550°C to 650°C and 2) constant displacement, stress relaxation data obtained from creep-fatigue tests at 650°C. Samples in the heat-treatment conditions of solution-treated, aged, and simulated ‘heat affected zone’ have been assessed. The standard RCC-MR model was fitted to the constant load data and provided good predictions of forward creep. However, when this model was used to predict stress relaxation it was observed that the model significantly over predicted creep strain rates and therefore the level of stress drop during each cycle. During constant load tests the stress remains relatively constant (noting that true stress does increase a small amount prior to rupture). However, in relaxation tests the stress varies significantly over the dwell. Due to the poor predictions of stress relaxation it was hypothesised that the fitted model did not capture the stress dependence of creep appropriately. The RCC-MR model was therefore modified to include a primary and secondary threshold stress term that is a function of the accumulated creep strain. This work indicates that the RCC-MR model, modified to include threshold stresses, can be used to provide good predictions of both forward creep and stress relaxation in Type 321 stainless steel. Further work is required to validate this model on stress relaxation data at additional temperatures and lower start of dwell stresses.

Liquid Cs, Te-lnduced fatigue embrittlement of cold-worked 316 stainless steel

1986 ◽  
Vol 17 (11) ◽  
pp. 2090-2093 ◽  
Author(s):  
Martyn G. Adamson ◽  
William H. Reineking ◽  
Sam Vaidyanathan
Keyword(s):  
Stainless Steel ◽  
316 Stainless Steel ◽  
Cold Worked
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