TECHNOLOGICAL WAYS TO CREATE COMPOSITE MATERIALS BASED ON HEAT-RESISTANT REFRACTORY COMPOUNDS (review)

The article discusses the main technological approaches to obtain heat-resistant and heat-resistant materials based on compounds in the Ni–Al system in order to use them in promising products of aviation and rocket technology. It is shown that when receiving materials based on compounds in the Ni-Al system, a phase of eutectic origin is formed based on the Ni3Al compound, which reduces the technological plasticity of the alloys of this system. The use of powder metallurgy methods eliminates such phases in the structure of alloys obtained using granule metallurgy technology, as well as with the use of special methods of powder metallurgy. Technological approaches are presented to obtain similar materials using powder metallurgy methods combined with thermomechanical processing.

ANALYSIS OF THE EFFECT OF HEAT TREATMENT ON THE STRUCTURE AND MECHANICAL PROPERTIES OF BARS MADE OF VT47 TITANIUM ALLOY

The article presents the results of a complex of studies on the analysis of the microstructure, as well as the determination of the mechanical properties under tension, shear resistance and upsetting at room temperature of rolled bars made of pseudo-β-titanium alloy VT47. A comparative analysis of the obtained research results is carried out, showing the dependence of the mechanical properties of rolled bars on various heat treatment modes, aimed at providing increased technological plasticity of the material and strengthening heat treatment.

Structure and characteristics of boron-containing steels for fasteners

According to TU 14-1-4486-88 and TU 14-1-5490-2004, in accordance with international standards DIN EN 10263-4, OJSC «BSW – Management Company of the Holding «BMC» produces hot-rolled products of the following grades of steel: 20Г2Р, 30Г1Р, 20MnB4, 30MnB4 and 32CrB4 microalloyed with boron. They are used for the manufacture of fasteners instead of previously used steels 35X, 38X and 40X. The use of boron-containing steels reduces the surface defects of hardware; to increase the stability of the mechanical properties of bolts, screws, studs, strength class 8.8 and 10.9 by GOST 1759.4-87; to achieve a high level of toughness at negative temperatures. It is shown that steel 20Г2Р provides stable mechanical properties of products up to M27 (in contrast to steel grades 35X, which are designed exclusively for bolts of class M16 8.8). The boron-containing steels in the delivery state with the structure of granular perlite have high technological plasticity – in the cold, the bolt head is formed and the thread is rolled without tearing in the thread hollows, as is the case with chromium steels of type 40X. It was found that their ductility increases due to the low content of carbon and chromium, as well as the formation of dispersed carbonitride-boride phases of a globular form.

Forming of the properties of an alloy on a Co-Cr-basis using casting-deformation technology

The article describes the method of obtaining a special medical alloy based on Co-Cr, which is also used to create implants for large joints of a man (hip and knee). The analysis of the optimal relationship between the alloy components is carried out. Also in this article the results of investigations of technological plasticity, microstructure, phase composition of samples from alloy are presented. Co-Cr analysis, subjected to longitudinal draft and extrusion.