Hot-forged wear-resistant powder meterials based on stainless steels of the austenitic class

The microstructure, tribological and physicomechanical properties of hot-forged composites based on stainless steel of the austenitic class with additions of carbon, Cr₃C₂ and MoS₂ are studied. The possibility is established of using these composites for powder structural articles resistant to wear and corrosion. __________ Translated from Poroshkovaya Metallurgiya, Nos. 1–2(447), pp. 26–35, January–February, 2006.     

Influence of grain size and porosity on the high-temperature friction of titanium carbide

Conclusions It was established that in friction of a TiC-TiC pair in vacuum the coefficient of friction at 250C and the wear rate at 1250C are practically independent of grain size. At higher temperatures these characteristics have an inverse relationship to grain size.It was shown that with an increase in porosity both the wear rate and the coefficient of friction increase. With an increase in temperature the influence of porosity on the wear rate decreases.With variations in porosity in the 1–10% range, in grain size in the 1–50 m range, and in temperature in the 20–1500C range the wear rate changes within limits of 10–45% and the coefficient of friction within limits of 3–35%.Translated from Poroshkovaya Metallurgiya, No. 9(297), pp. 56–61, September, 1987.     

Formation of Crystal Structure in Hot Forging of Powder Carbon Steels

Powder Metallurgy and Metal Ceramics - The crystal structure acquired by powder steels produced from undoped iron powder and mixtures of iron with 1.0 or 1.5% graphite in hot forging was studied by...     

Reducing the vibration of a chevron gear transmission

A mathematical model is proposed for tooth vibrations in chevron gear transmissions. Methods of reducing the vibrations in spiral engagement are outlined.     

Investigating the dependence of the properties of sintered boron-containing steels on conditions of synthesis and the content of employed foundry alloys

Results from investigating the effect of technological conditions for the synthesis of powdered boron-containing foundry alloys on their chemical and phase compositions and the content of foundry alloys in the charge on the structure and properties of sintered steels fabricated using them are presented. It is shown that using denser briquettes obtained at a pressure of ??700 MPa allows us to reduce substantially boron evaporation through the gas phase during the synthesis of foundry alloys, relative to briquettes compacted at lower pressures. Using an elevated foundry alloy synthesis temperature (1200°C) leads to higher density of the post-sintered material, and thus to enhanced strength characteristics. Increasing the boron content in the initial charge increases the hardness and lowers the strength of sintered steels, while the curve of the strength??s dependence on the boron content after thermal treatment peaks at ??0.8% B.     

The hydrogen bond in thermal strengthening of aramid systems containing polyamide-benzimidazole fragments

An IR-spectroscopic study was conducted in aramid systems containing benzamide and benzimidazole fragments which allowed evaluating the character and magnitude of the enthalpy of formation of intermolecular hydrogen bonds under the effect of high temperatures. Strengthening of the H bond in benzimidazole groups and weakening of the bond in benzamide (benzimidole) groups were demonstrated. The possible co-existence of imidole-quinoid groups with benzamide and imidazole fragments was established. Polarization studies of the oriented state demonstrated high anisotropy of absorption for most vibrations in the 400–4500 cm^-1 region.