Kinetics of small fatigue cracks in steel during cyclic loading

The kinetics of development of fatigue microcracks in a high-strength 08Kh14AN4MD steel is studied when a cantilever specimen with several notches is subjected to rotational bending tests. The specific feature of the tests consists in the fact that, when the specimen is loaded at a constant load, different stress amplitudes are realized in different notches. As a result, after the sample has failed across the section with the maximum stress, a longitudinal polished section of the specimen contains fatigue cracks having nucleated in the mouths of the other notches at lower stress amplitudes. A relation between inflection points in the fatigue curve and the conditions of local and developed yield in a notch has been established. Fatigue fracture mechanisms at a superhigh number of loading cycles are studied, and their relation to the structure near a crack is found. A rapid method for estimating the fatigue limit at a superhigh number of loading cycles is proposed.     

Effect of thermal cycling on the stress-strain state of a rotating disk

The effect of repeated thermal cycling on the stress-strain state of a rotating disk is investigated. It is demonstrated that repeated temperature cycling in a given regime nearly doubles the deformation of the rotating disk. This suggests the probability of a major influence of thermal cycling on the deformed state of the rotating disk.Translated From Problemy Prochnosti, No. 1, pp. 57–62, January, 1991.     

Corrosion resistance of a bent plate from a high-nitrogen nonmagnetic 05Kh22AG15N8M2F steel in aggressive media

The corrosion resistance of the convex and concave sides of bent plates from a high-nitrogen non-magnetic steel has been studied in aqueous solutions of sulfuric and hydrochloric acids. Weighing and hydrogen methods are used to control the corrosion rate of bent-sample sides and to find a number of effects that complement the picture of the stress corrosion of iron alloys and support the existence of the mechanochemical deformation sign effect.     

Deformability of ShKh15 steel during cold plastic deformation

The effect of anomalous structural constituents in ShKh15 steel on its technological ductility during cold deformation has been studied. Additional high tempering of hot-rolled billets subjected to spheroidizing annealing is shown to remove retained lamellar pearlite and needle carbides, increasing the technological ductility of this ball-bearing steel.     

Prototype of the 1/6 MOL Module of a Superpower Pulse Generator

This paper considers problems related to the creation (as part of the Baikal Program) of a super-power pulse generator intended for inertial confinement fusion applications and having pulse parameters of ～10 MV, ～50 MA, and ～150 ns. A MOL facility (3.7 MA, 5 MV, and 150 ns) with a six-module plasma opening switch (POS), operating as an output pulse compression stage, is being developed to test the circuit solutions of this generator. The design for the prototype of one POS module, referred to as the 1/6 MOL test bench, is presented. The results from experimental tests related to POS performance within the MOL facility are reported.     

Structure and mechanical properties of a nonmagnetic high-nitrogen corrosion-resistant 05Kh22AG15N8M2F cast steel produced by high-gradient directional solidification

The structure and properties of an austenitic high-nitrogen corrosion-resistant 05Kh22AG15N8M2F cast steel produced by high-gradient directional solidification (HGDS) and equiaxed-grain solidification (ES) have been studied and compared. In contrast to ES, HGDS allows one to substantially decrease the degree of dendritic segregation of alloying elements, to eliminate porosity, and to increase the strength and plasticity of the steel.     

A microexplosion technique for modeling large-scale ejection explosions

Based on the theory of approximate similarity of soil-ejection underground explosions, a technique for laboratory modeling of this phenomenon by microexplosions has been developed. This paper describes the experimental setup and reports some results obtained from experiments on selection of a soil simulator and from experiments on elucidation of the atmospheric-pressure role with varied scales of the phenomenon. The results are interpreted by comparing them with full-scale explosions and theoretical data.Russian Research Institute of Technical Physics, 454070, Snezhinsk. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 102–109, March–April, 1995.