On the selection of allowable stresses in the strength analysis of structures for cryogenic applications

The methods developed at the Pisarenko Institute of Problems of Strength of the National Academy of Sciences of Ukraine for determining the allowable stresses for structural elements operating at cryogenic temperatures are considered. The methods make it possible to take into account the effect of the low-temperature hardening and the softening electromagnetic action on the value of allowable stresses.     

Strength and crack resistance of chromium-nickel-manganese 03Kh19AG3N10 steel in the temperature range 293–4.2 K

We present the results of the experimental investigation of the characteristics of strength and crack resistance of chromium-nickel-manganese 03Kh19AG3N10 steel in the temperature range 293–4.2 K under static (in the initial state and under the action of pulses of electric current) and dynamic loads. We consider some distinctive features of the process of the discontinuous yield of steel at a temperature of 4.2 K and its influence on the kinetics of fracture processes. The comparative analysis of temperature dependences of the characteristics of strength, plasticity, and crack resistance of 03Kh20N16AG6, 03Kh20N16AG6Sh, and 07Kh13N4AG20 steels extensively used in cryogenic engineering and 03Kh19AG3N10 steel demonstrates that 03Kh19AG3N10 steel can be used in the temperature range 293–4.2 K. Translated from Problemy Prochnosti, No. 3, pp. 90–95, May–June, 1997.     

Fracture strength of economically alloyed steel ON9 in cooling to 4.2 K

The article deals with the effect of cooling steel ON9 to 4.2 K on the change of its strength and crack resistance under static loading. Special features are noted of the development of failure of specimens with a crack in three-point bending under conditions of cryogenic temperatures. It was established that the mechanical characteristics change monotonically, and the stress intensity factor, which somewhat increases in the temperature range 293–123 K, noticeably decreases upon cooling to below 123 K.Translated from Problemy Prochnosti, No. 9, pp. 72–75, September, 1990.     

Effect of cooling to 4.2 K on the strength and cracking resistance of the parent metal in welded joints in 07Kh13N4AG20 steel

The results are presented of experimental examination of short-term strength and cracking resistance of the parent metal and welded joints in 07Kh13N4AG20 steel in the temperature range 293–4.2 K. The mechanical characteristics of the welded joint in the examined steel are compared with the characteristics of 12Kh18N10T and 03Kh20N16AG6 steels. The results show that the mechanical properties and crack propagation resistance of the weld metal in 07Kh13N4AG20 steel are similar to those of the parent metal.Translated from Problemy Prochnosti, No. 9, pp. 45–48, September, 1990.     

Propagation of cracks in structural alloys at a temperature of 4.2 K

We study distinctive features of the process of crack propagation in structural materials under conditions of discontinuous yield and under the action of pulses of electric current at a temperature of 4.2 K. The kinetics of fracture processes in steel under the indicated conditions is studied by the method of stereofractographic analysis. We investigate the applicability of approaches to the evaluation of the characteristics of the crack-growth resistance of materials that take into account the effect of discontinuous yield and pulses of electric current on the process of formation of a plastic zone at a crack tip. Translated from Problemy Prochnosti, No. 6, pp. 36–40, November–December, 1997.     

Radiation-Induced Embrittlement of WWÉR-440 Reactor Pressure Vessel Steel under Loading

The results of evaluating the reference temperature T ₀ are presented and Master Curve is constructed from the experimental data for steel 15Cr2MoVA (base metal of WWÉR-440 reactor pressure vessel) in three states: unirradiated, irradiated, and irradiated under stress. It is shown that mechanical load, which simulates the coolant pressure, accelerates radiation embrittlement, whose contribution is comparable to that of neutron irradiation.     

Cold hardening of steels under conditions of inhomogeneous stress and action of electric current pulses

The possibility to assess cold hardening of steels in the presence of stress concentration by means of structural-strength factors used in the engineering practice is considered. A modified system of structural-strength factors is proposed, which allows one to take into account the effect of individual factors (cryogenic temperature, stress concentration, action of electric current pulses) or their combination on the efficiency of steels in the case of inhomogeneous stress. __________ Translated from Problemy Prochnosti, No. 4, pp. 40–49, July–August, 2007.     

Determination of Reference Temperature T0 for Steel JRQ in an Unirradiated State and Construction of a Master Curve

This paper considers the results of testing reactor steel JRQ involving determination of the fracture toughness and the reference temperature T₀, construction of a Master Curve, and evaluation of the boundaries of regions with different failure probability. The tests were conducted on small specimens (1/2T) made from blocks of steel JRQ supplied by the IAEA within the framework of the Round Robin program.