Analysis of the composition and processing technologies of dispersed iron‑containing waste

The article discusses the types of various dusty iron‑containing waste generated in metallurgical and foundry production. Rational waste processing technologies are considered. The analysis of the chemical composition of iron‑containing waste, morphology and particle size is presented. Variants of processing and use technology that are acceptable for the conditions of the Republic of Belarus are proposed.

Technology and equipment of vertical‑stack molding for the production of castings without pattern drafts

The article reports on the new technology and equipment of vertical‑stack molding (VSM), created by OJSC “BELNIILIT” for the manufacture of vertical‑stack molds. The development is intended for the production of molds and cast blanks of oil, which are later used for the manufacture of piston rings of internal combustion engines.The difference between the above‑mentioned technology and traditional methods of VSM is the use of models without drafts. The development is export‑oriented and has a great economic effect for ring manufacturers due to the absence of drafts on castings, since part of the mechanical operations for their processing is excluded, the metal consumption of blanks is reduced, the production spaces required in this regard are reduced, the necessary labor supply is reduced, etc.OJSC “BELNIILIT” has successfully carried out experimental design and technological work on the new scientific and technical products creation, which are of great interest to the world manufacturers of piston rings. An industrial sample of a molding machine and a mold manipulator were manufactured.

Selection of the chemical composition of steels and their thermal hardening mode using a computer program

The relationships between the parameters of the structure of heat‑treated steels and their abrasive wear resistance are established. At all temperatures of the final tempering of hardened steel, there is a direct relationship between its structure parameters (the number of elements in a solid solution, the density of dislocations, the size of cementite particles and the intercementite distance) and wear resistance when sliding friction against loose abrasive particles. A computer program has been developed to select the chemical composition of the steel grade and methods of thermal hardening in order to ensure the required wear resistance.

Investigation of the microstructure evolution of 7CrMn2WMo economy‑alloyed steel in a new design forging tool implementing shear deformations

In this paper, a new forging technology realizing intense shear deformations during processing with a tool for its implementation was considered, and the influence of the proposed forging technology on the microstructure evolution of 7CrMn2WMo economy‑alloyed steel was revealed. A comparative analysis of the results of the microstructure evolution when forging blanks made of 7CrMn2WMo steel according to the proposed and current technologies proves the usefulness of a new design tool instead of the currently used flat strikers, since forging in the proposed forging tool provides more intensive and uniform processing of the cast structure over the entire section of the workpiece compared to forging in the flat strikers.

Structural‑phase composition of a gas‑thermal coating of Fe‑Cr‑Ni‑Al pseudo alloy subjected to annealing

The structural‑phase state of the gas‑thermal coating made of Fe‑Cr‑Ni‑Al pseudo‑alloy in the initial state, as well as after annealing in the temperature range 550–650 °C for 20–60 minutes, has been investigated. It has been established that the phase composition of the Fe‑Cr‑Ni‑Al pseudo‑alloy in the initial state includes mainly Al and α‑Fe, and its porosity does not exceed 3–5 vol.%. Annealing of a thermal spray coating from a pseudo‑alloy at temperatures of 550–650˚C for 20–60 minutes leads to the release of iron‑aluminum intermetallic compounds Fe3Al, Al13Fe4 and Al5Fe2, an increase in hardness and porosity.

Theoretical and technological aspects of production mechani‑cally alloyed powders for the production of coatings and products by additive methods

The established regularities of the formation of powders based on iron and nickel, obtained by the method of mechanical alloying and intended for the deposition of thermal spraying coatings, as well as the manufacture of products by layer‑by‑layer synthesis. The structure, phase composition and properties of materials are investigated. Powders consist of particles with a size of 20–70 microns, differ in the submicrocrystalline type structures, and nonequilibrium phase composition. Thermal spray coatings made of them have a set of properties that significantly exceed the properties of coatings made of commercially available materials. The diameter of the grains of the material obtained by the SLМ method from the synthesized powder is 1.5–2.0 times smaller than that produced from the powder of 316L steel, and the heat resistance is higher.

Automatic control of the physical and mechanical properties of the raw sand‑clay molding mixture in the process of mixture preparation in the new developments of OJSC “BELNIILIT”

OJSC “BELNIILIT” specialists have developed a method and an automatic device for monitoring and managing the quality of raw sand‑clay molding blend, which is based on the integrated control – compaction of the molding blend principles, measurement of humidity and strength in the raw state, measurement of temperature directly in the process of mixture preparation. The equipment is integrated into existing automated mixture preparation complexes manufactured by OJSC “BELNIILIT”, it is possible to install on old design mixers.

Nonoxidizing heating of chip‑powder dispersions of ferrous metals in hydrocarbon atmosphere

The process of inorganic and organic components temperature transformation of metal waste into solid and gaseous products in a continuous hot briquetting muffle furnace has been studied. The composition of the hydrocarbon atmosphere formed in the muffle under conditions of limited access to the oxidizer has been determined. It is shown that the thermal destruction of the coolant oil phase proceeds according to a complex mechanism of consecutive reactions, including polycondensation, polymerization, and deep compaction with a constant decrease in the hydrogen content and ends with the formation of a coke‑like carbon residue on the surface of metal particles and an air suspension of finely dispersed carbon particles (smoke). When it is heated to hot briquetting temperatures of 750–850 °C, chemically active dispersions of ferrous metals are protected from oxidation first by a hydrocarbon gas with a density of 9.0–13.5 kg/m3, then by a pyrocarbon coating with a thickness of 0.1–0.3 mm up to the completion of the processes of pressing and cooling the briquette.

Determination of destruction cause of experimental mill roll of stand roughing group of mill 150.

High quality of purchased resources plays a critical role under the conditions of severe international competition. Raw materials, materials and components are purchase for product production and their quality is an essential part in the production of steel at OJSC “BSW – Management Company of the Holding “BMC” holding». The problem of excessively high level of dynamic loads is especially acute for roughing stands. The main reasons for dynamic overloads are intense transient processes occurring in the rolling cycle, the presence of elastic constraints and gaps in the system, imperfection of electric drive system and errors made during development. Therefore, there is a need for selection of material and manufacturing technology for mill rolls capable to withstand such loads for a sufficiently long period. Investigations of destruction causes of experimental mill roll of stand roughing group of mill 150 of section rolling shop at OJSC “BSW – Management Company of the Holding “BMC” holding were carried out. Main classification features are established based on the analysis of the fracture. The results of metallographic studies of microstructure and chemical composition of central and subsurface zone roll fragments are presented. The reason of destruction of experimental mill roll was discovered – nonconformance of roll material grade with the requirements of technological instructions and normative documentation for rough group of stands No. 1–3