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1.Small additions of REM (0.1–0.15%) to structural steels have no essential effect on the ductile-brittle transition temperature after quenching and tempering or embrittling treatment.2.Alloying of structural steels with large quantities of REM (0.4–0.65%) shifts the ductile-brittle transition temperature to lower temperatures and practically eliminates susceptibility to reversible temper brittleness.3.REM does not enter into the solid solution and does not enrich the grain boundaries but is found only in nonmetallic inclusions.4.The main reason for the substantial reduction of the ductile-brittle transition temperature of steels alloyed with REM is that REM combines harmful impurities (phosphorus and its analogues) in nonmetallic inclusions.

Conclusions 1.The existing methods of passing no-load discharges through turbines of low-head hydrostations do not provide reliable operation of the units owing to a considerable increase of the dynamic loads on the runner blades, other elements of the units, and structural members of the station.2.The proposed method of passing the no-load discharge with the use of dynamic braking according to the given law reduces all dynamic loads with a sufficiently high discharge capacity of the turbine. This is confirmed by full-scale tests of the model. The use of the given method can produce a considerable effect both at existing and newly designed hydrostations.3.The high values of efficiency and minimum dynamic loads on the pump units operating in the turbine regime allow using the impellers of axial-flow pumps as turbines and motors as generators.

Conclusion The developed method of determining a shutoff closing law provides a minimum increase of pressure and dynamic loads on the unit.

1.Steel 30Kh3NM3FTs can be used in place of steel 3Kh2V8F for parts of presses with sections as large as 200 mm that operate under static applied loads.2.Due to the high stability of austenite resulting from the addition of nickel, steel 30Kh3NM3FTs can be air hardened.3.The ultimate tensile strength at standard and elevated temperatures, red hardness, creep strength, and other properties of steel 30Kh3NM3FTs are very similar to those of steel 3Kh2V8F, while the ductility and fracture toughness are higher.4.Production tests have shown that the resistance of tools made of steel 30Kh3NM3FTs is equal to that of tools made from steel 3Kh2V8F.

1.Economically alloyed steel 38Kh2NM in forgings up to 500 mm in diameter has a combination of mechanical properties equal to that of steel 34KhN1M and corresponds to strength category KP 55-KP 65 (GOST 8473-70).2.Alloying of steel 38Kh2NM with ~0.1% V increases the strength characterististics without reducing the ductility or fracture toughness.

With the help of electron microscopy, digital processing of images and u.v. -visible spectrophotometry, the relationship between the maximum in the light extinction spectrum of colloidal particles of silver and gold (in a medium with refraction coefficient n20D = 1·5) and the maximum in their size distribution was studied. Sizes of particles and maxima in their extinction spectra are in the range of 0·3-0·35 nm, 430-830 nm (Ag) and 0·2-0·25 nm, 540-830 nm (Au) respectively. An analysis of the differences between theoretical and experimental dependence is also given.

The fatigue properties of rigid polymers used for making harmonic drive components have been investigated. Certain data on the fatigue of flexible shells under complex loading conditions have been obtained. The effect of the polymer structure on the fatigue properties of a series of compounds with various antifriction fillers and plasticizing additives is evaluated.