Design of minimum-volume foundations

Conclusion It is possible to obtain a minimum-volume foundation only when the calculations of the base and body of the foundation are considered simultaneously from the same viewpoint and when the ratios of the dimensions of the undersurface are not assigned but established in a calculation based on knowledge of the main regularities of the change of volume of the slab part of the foundation.Moscow Civil Engineering Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 32–34, May–June, 1974.     

A small tunnel kiln for firing corundum refractories

Conclusions The special features of the small (working volume capacity 6. 8 m³) tunnel kiln for firing corundum refractories are: firing with a gas-air mixture, absence of combustion chambers between the charges, absence of end doors, and slow kiln truck speed (13 cm/h). The corundum bricks are fired in the kiln for 136 h at 1660°C.The gaseous medium of the firing zone contains oxidizing and reducing components.The faults of the kiln are: nonuniformity of the firing of the bricks, inadequate firing temperature level, and unsatisfactory performance of the first six positions of the heating zone where heating takes the form mainly of a thermal shock in the region of the last two (in the direction of the gas flow) pairs of connections for the extraction of the combustion productsTo improve the quality and economics of the firing process, it will be necessary to improve the heat insulation of the kiln channel, to provide channels in the floor, and to modify the heating and gas extraction systems.Translated from Ogneupory, No. 7, pp. 8–15, July, 1977.     

Improved quality zircon nozzles for continuous steelcasting

Conclusions An incorrect drying schedule is the main source of internal cracks in zircon nozzles. Cracking can be prevented either by drying the nozzles by an extended schedule (8 days at 30°C, 2 days at 50°C, and 1 or 2 days at 110°C) or by using ACPB instead of s. s.l. and drying the nozzles by a shorter schedule.Translated from Ogneupory, No. 5, pp. 15–19, May, 1977.     

High-pressure-torsion deformation of melt-spun Nd<Subscript>9</Subscript>Fe<Subscript>85</Subscript>B<Subscript>6</Subscript> alloy

The effect of severe plastic deformation by high-pressure torsion (HPT) at room temperature and subsequent annealing on the magnetic properties and structural transformations of the melt-spun alloy (MSA) Nd₉Fe₈₅B₆ is studied. The melt-spun ribbons in three structural states, such as nanocrystalline, mixed amorphous-nanocrystalline, and quasi-amorphous, have been subjected to deformation. In the nanocrystalline alloy, HPT leads to the decomposition of part of the Nd₂Fe₁₄B phase into the amorphous phase and α-Fe nanocrystals. The deformation of the alloy in the quasi-amorphous state leads also to the precipitation of a great amount of α-Fe nanocrystals; in this case, the amorphous matrix is depleted of iron. During the HPT of the MSA in the mixed amorphous + nanocrystaline state, both structural transformations occur. The annealing of deformed samples at above 500°C restores the two-phase (Nd₂Fe₁₄B + α-Fe) nanocrystalline state. This is accompanied by increasing magnetic hysteretic properties. The HPT has been found to suppress the formation of nonequilibrium magnetically soft phases, such as NdFe₇ and Nd₂Fe₂₃B₃, that precipitate upon annealing of the melt-spun amorphous alloy. This promotes the formation of an optimum nanocrystalline structure of the α-Fe/Nd₂Fe₁₄B composite material and an increase in its magnetic hysteretic properties because of enhancement of the intergranular exchange interaction. Compact micromagnets 6–15 mm in diameter and 0.2 mm thick, which were prepared from the Nd₉Fe₈₅B₆ alloy using HPT and subsequent annealing, exhibit the following characteristics: B _r = 11.4 kG, H _c = 5.4 kOe, and (BH)_max = 17.1 MG Oe.     

Optimizing heat treatment regimes for high-strength weldable, sparingly alloyed steels

It is important to devote maximum attention to the heat treatment of temperable high-strength weldable steels (σ_0.2≥700 MPa) in which the expensive alloying elements (Cr, Ni, Mo, etc.) are partially or fully replaced by microadditives (V, Ti, etc.). The present paper concerns the effect of the temperature-and-time heat treatment parameters on the structure, the grain size, and the mechanical properties of sparingly alloyed steel 15G2KhNMFTR. The heat treatment regime is optimized. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 2–5, August, 1998.     

Specific Features of Electroplastic Effect in Mono- and Polycrystalline Aluminum

Metal Science and Heat Treatment - The deformation behavior of mono- and polycrystalline aluminum under tension with the impact of different modes of current has been studied. It is shown that the...     

Electrical Discharge Machining by Structural-Steel Electrodes

Russian Engineering Research - An approach is outlined to selecting conditions of electrical discharge machining such that coatings with the required functional properties are formed on the working...