Corrosion Fatigue of Austenitic Stainless Steels for Nuclear Power Engineering
Significant structural steels for nuclear power engineering are chromium-nickel austenitic stainless steels. The presented paper evaluates the kinetics of the fatigue crack growth of AISI 304L and AISI 316L stainless steels in air and in corrosive environments of 3.5% aqueous NaCl solution after the application of solution annealing, stabilizing annealing, and sensitization annealing. Comparisons were made between the fatigue crack growth rate after each heat treatment regime, and a comparison between the fatigue crack growth rate in both types of steels was made. For individual heat treatment regimes, the possibility of the development of intergranular corrosion was also considered. Evaluations resulted in very favourable corrosion fatigue characteristics of the 316L steel. After application of solution and stabilizing annealing at a comparable ∆K level, the fatigue crack growth rate was about one half compared to 304L steel. After sensitization annealing of 316L steel, compared to stabilizing annealing, the increase of crack growth rate during corrosion fatigue was slightly higher. The obtained results complement the existing standardized data on unconventional characteristics of 304L and 316L austenitic stainless steels.
Influence of Technological Factors on Fatigue Properties of Steel Sheets
the fatigue crack initiation and the fatigue limit under one-sided bending (R (cid:4) 0.1). It indicates a positive effect on the above-mentioned characteristics if strips are loaded under one-sided bending from the side where residual compressive stress is formed during levelling. By blasting a sheet made of steel grade 11 375.1, the fatigue limit under symmetrical flat bending was increased due to the hardening and formation of residual compressive stress. The paper also indicates risks connected with blasting, influencing the fatigue life.
The effect of temperature and electrostatic field on tungsten and iridium field-ion emitters
Abstract Studies have been made of the effect of heating tungsten and iridium field-ion emitters in the presence of an applied electrostatic potential. Although the original intention was to induce plastic deformation as a result of field stresses, and hence to investigate surface slip step formation, it is clear from the image contrast observed that, rather than inducing slip, the procedure instead leads to the formation of fine-scale thermal facets. Earlier reported attempts to deliberately induce surface slip in this way must also be reinterpreted in terms of thermal facet formation.