Variation of the creep limit and structure of a welded joint in PT-3V titanium alloy under cyclic loading. Report 1

The creep of PT-3V titanium alloy and of a butt welded joint in this alloy (PT-2V filler material) was investigated on cylindrical specimens 7 mm in diameter with a gage length of 50 mm. The plane of the weld 10-mm wide, produced by manual submerged-arc welding, was situated in the center of the specimen in the direction normal to its longitudinal axis. The results show that in the examined cyclic stress amplitude range the preliminary cyclic loading lasting 5·10 ⁴ cycles with a frequency of 35 Hz increases the cyclic creep limit of PT-3V alloy by 11% and the static creep limit of the welded joint by 19%. This variation of the mechanical properties can be regarded as one of the reasons for the positive effect of the vibrotreatment technology, used in industry, leading to stabilization of the dimensions and form of components.Translated from Problemy Prochnosti, No. 4, pp. 27–33, April, 1996.     

Variation of the creep limit and structure of a welded joint in pT-3V titanium alloy under cyclic loading. Report 3

The metallographic methods and microanalysis were used for investigation of the welded butt-joint specimens from PT-3V titanium alloys. The specimens were in initial state and after cyclic loading. Duration of loading was 5·104 and 1·107 cycles on a frequency of 35 Hz. The stress amplitude was 150 MPa; this value is below the endurance limit of weld material. The polished sections for investigations were cut out from a working part of specimens, which contains all zones of weld including the base metal. The plane of the polished section was disposed parallel to the surface of the weld and the axis of the polished section was located perpendicularly to the axis of the weld. The results show that migration of interstitial impurities takes place to boundaries of weld zones and regions of primary segregation of substitution elements. This process occurs under the action of cyclic loading that is followed by reduction of relative density of movable dislocations and length of dislocation segments, which are described in Communication 2. The mentioned causes lead to stabilization of weld material structure and enable an increase in the cyclic and static creep limits as is described in Communication 1. The physical processes, responsible for stabilization of dislocation structure and growth of creep stresses, are mainly completed after 5·104 cycles of loading. Translated from Problemy Prochnosti, No. 5, pp. 101–108, May, 1996.     

Corrosion resistance of PT-3V titanium alloy and its welded joints in sulfide solutions

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 2, pp. 101–103, March–April, 1990.     

Fatigue strength and cyclic crack resistance of titanium alloy VT3-1 in different structural states. Communication 2. Procedure for considering the effect of structure on fatigue limit

On the basis of experimental results presented in communication 1 for a study of the fatigue strength of two-phase titanium alloy VT3-1 in different structural states it is shown that the fatigue limit for the alloy increases with a reduction in the average size of a structural element critical for cyclic strength. A numerical model is developed by means of linear fracture mechanics approaches which makes it possible from available data about the size of structural parameters for the alloy to predict the fatigue limit of smooth specimens.Translated from Problemy Prochnosti, Nos. 5–6, pp. 12–17, May–June, 1995.     

Effect of the stress ratio on the fatigue and cyclic creep of low alloy steels. Report 2

Methods have been developed for experimentally determining the fatigue limit, which has been called by the authors the minimum cyclic creep limit, and the stess limits at various cyclic stress ratios R, called the cyclic creep limits. During the cyclic creep limit tests, levels of residual stresses are achieved which are equal to the residual stresses obtained at the yield point. It has been shown that with increase in the value of R, the cyclic creep limits increase, and the minimum value of the cyclic creep limit is less than the corresponding yield points of steel 09G2 by about 8 %, and for steel 14Kh2GMR by about 15 %.Translated from Problemy Prochnosti, No. 2, pp. 27–31, February, 1991.     

High-temperature creep and long-term strength of structural elements under cyclic loading

We present a method for solving problems of high-temperature cyclic creep and damage accumulation in structural elements. The asymptotic expansion and averaging techniques both over the period of forced vibrations of a body and that of slowly varying loads are used for the set of equations describing the creep and damage processes in thin-walled structural elements. __________ Translated from Problemy Prochnosti, No. 5, pp. 45–53, September–October, 2008.     

Effect of the stress ratio on the fatigue and cyclic creep of low alloy steels. Report 1

The fatigue resistance of low-alloy steels 09G2 and 14Kh2GMR over the stress ratio range of 0 R < 1 has been studied. The limiting stresses under which these steels can be used has been determined. It was established that with increase in R, the fatigue limit shifts into regions of greater endurance.Translated from Problemy Prochnosti, No. 2, pp. 24–27, February, 1991.