The article presents the waste generated during the production of hot-dip galvanizing. The analysis of the proposed methods of using these wastes in the production of zinc-containing coatings is carried out. It is shown that hard zinc can be successfully used in the compositions of saturating mixtures during thermal diffusion galvanizing of steel products and obtain high-quality coatings. The disadvantages include the need for grinding hard zinc.The dispersed waste of hot-dip galvanizing production, which is formed as a result of blowing pipes with superheated steam, can be used as a cheap substitute for expensive zinc powder in the compositions of zinc-filled paints. For paints, a fraction of 2–15 microns is used, which is 27 % of the total fractional composition. Therefore, in order to use a wider range of values of the fractional composition of dispersed waste to obtain zinc coatings and thus ensure the recycling of zinc into industrial circulation, the authors of this article plan to optimize and develop the compositions of powder compositions and the technology of thermal diffusion saturation of steel products based on zinc-containing waste.

The article presents the waste generated during the production of hot‑dip galvanizing. The results of the study of the particle size distribution of zinc dust showed that its particle size distribution in the size range of particles ≤ 250 μm, the proportion of which is 87 wt.%, corresponds to the fractional composition of standard powder zinc. In ash, the number of particles up to 250 microns in size is approximately 35 wt.%. Studies of the chemical and phase composition of the hot‑dip galvanized waste – zinc dust made it possible to establish that the zinc content of the waste approximately corresponds to powder zinc (GOST 12601). The proportion of pure zinc in dust is 95 %. Chemical and phase analyzes of the ash have shown that it contains zinc oxides, pure zinc and zinc chlorides. Zinc chlorides, in turn, can be a supplier of chlorine ions in thermal diffusion galvanizing. In this regard, it is of interest to use ash in the composition of the powder composition as an activating and zinc‑containing component. The results of the analysis of the conducted studies of hot‑dip galvanizing wastes – zinc dust and soot show that they are promising for their use as components in saturating mixtures in the production of zinc coatings by chemical‑thermal treatment. This will reduce the cost of galvanized products and ensure the recycling of zinc into industrial circulation.

A comparative analysis of the corrosion properties of zinc-containing coatings obtained on the basis of metallic powder zinc and dispersed hot-dip galvanized waste has been carried out. The results of a study of the corrosion resistance of zinc-containing coatings by the electrochemical method and in a salt spray chamber have shown that coatings obtained on the basis of dispersed hot-dip galvanized waste are not inferior in protective properties to coatings based on powder standard zinc.

A comparative analysis and assessment of the impact of the method of introducing the modifying additive in the form of dispersed and ultrafine particles into the electrode coating on their welding-technological properties and mechanical properties of the weld metal is carried out. It has been established that a modifying additive containing such chemical elements as barium, strontium, potassium, silicon, aluminum, vanadium is a mixture of stable alkaline-earth metal compounds in the form of carbonates and is inserted into the coating of the electrodes by applying its dry mixture into the composition prior to their crimping, allows to improve the welding-technological characteristics of the electrode and grind the structure of the weld metal, which contributes to the improvement of its mechanical properties particularly ductility.

The chemical and grain-size analysis of zinc dust – waste of hot – dip zinc plating were made. The research results showed that zinc dust is a dispersed waste with particles of mainly circular shape and sizes from 3 to 200 microns, and in chemical composition it mainly meets the requirements of ISO 3549. The presence of lead in the zinc dust composition, which is slightly higher than the acceptable level will be taken into account in the development of zinc-rich paints compositions. Analysis of the results of sieving of zinc dust showed that it contains particles of size  £ 15 µm, which is about 27% of its fractional composition and which can be recommended for the manufacture of zinc-rich paints.

The chemical and grain-size analysis of zinc dust – waste of hot – dip zinc plating were made. The research results showed that zinc dust is a dispersed waste with particles of mainly circular shape and sizes from 3 to 200 microns, and in chemical composition it mainly meets the requirements of ISO 3549. The presence of lead in the zinc dust composition, which is slightly higher than the acceptable level will be taken into account in the development of zinc-rich paints compositions. Analysis of the results of sieving of zinc dust showed that it contains particles of size £15 µm, which is about 27% of its fractional composition and which can be recommended for the manufacture of zinc-rich paints.

A comparative analysis and assessment of the impact of the method of introducing the modifying additive in the form of dispersed and ultrafine particles into the electrode coating on their welding-technological properties and mechanical properties of the weld metal is carried out. It has been established that a modifying additive containing such chemical elements as barium, strontium, potassium, silicon, aluminum, vanadium is a mixture of stable alkaline-earth metal compounds in the form of carbonates and is inserted into the coating of the electrodes by applying its dry mixture into the composition prior to their crimping, allows to improve the welding-technological characteristics of the electrode and grind the structure of the weld metal, which contributes to the improvement of its mechanical properties particularly ductility.

The mechanism of the formation of veinings on cast iron castings whose cores are made of a cold-hardening mixture is studied. It is shown that the cause of the formation of the veinings are the stresses in the surface layer of the core that arise when a-quartz is converted to a-tridymite. The possibility of reducing the number and size of veinings due to the selection of the composition of paints and the thickness of their layer on the surface of the rods was tested.

It is established that inclusion of the modifier into the electrode coating allowed to change the grains of the weld metal from 20–60 to 10–30 mm, to change its morphology and to improve the welding-technological properties of the coated electrode. It is shown that the modifying additive introduced into the coating of a welding electrode containing ultrafine particles in an amount of 1% of the weight of the dry charge had not deteriorated the technological parameters during manufacture, and the integral index of the different thickness (Desp) of electrodes with standard and experimental coatings did not add to the accepted value of 0.05. This indicates that the quality of the lubricating mass, its properties, the stability of the mass flow from the spinneret are satisfactory for both batches.

The influence of the complex modifier by chemical – active and surface-active additives of gray cast iron on the size of chill and on the width of molted iron zone was researched. The width of a chill zone and molted iron zones were measured at chank ends of various diameter cores. The cores were casted on a massive steel plate and also in standard chill tests. It was established that additional adding of surface-active bismuth in structure of various graphitizing modifiers promoted to reduce the width a chill zone and molted iron zones. It was established that the complex modifiers consisting of chemical – active and surfaceactive components are effective in fight with chill in cast iron castings and can be recommended for application in foundry shops of the entities of a machine-building profile for production of high-quality castings.

The foundry inoculant containing alkali-earth metals for smelting steel brand 45 L was tested in production conditions. Relationship of mechanical properties and castability on the number of the entered inoculant was established. It was defined the number of the inoculant allowing to improve properties.

The article presents the results of the tests on the wear resistance of chromium cast irons of different compositions obtained in sand forms. It has been shown that increase of the wear resistance and mechanical properties of the cast iron is possible to obtain using the casting in metal molds. A further increase in wear resistance of parts produced in metal molds is possible by changing the technological parameters of casting and alloying by titanium.

Comparative researches showed that sodium aluminate can be successfully used as a modifying addition into the foundry paints on the basis disthen-sillimanite and lignosulfonate, as well as the binder for the chill mould paints based on graphite.

The article presents the results of the tests on the wear resistance of chromium cast irons of different compositions obtained in sand forms. It has been shown that increase of the wear resistance and mechanical properties of the cast iron is possible to obtain using the casting in metal molds. A further increase in wear resistance of parts produced in metal molds is possible by changing the technological parameters of casting and alloying by titanium.

The foundry inoculant containing alkali-earth metals for smelting steel brand 45 L was tested in production conditions. Relationship of mechanical properties and castability on the number of the entered inoculant was established. It was defined the number of the inoculant allowing to improve properties.

The possibility of increasing the hardness (strength) nonburning-on coatings based on distensilimonita and lingosulfanata as binding by the addition of sodium aluminate and polyethylene glycol (PEG-200) was usearched. It was found that addition of these substances enhances strength for the first one temperature ranges 130–1200 oC, and for the second one – only after drying. It is shown that for distensilimonita zircon (ZrSiO 4 ) these substances provide high strength and as separate binders. But for paints based on Al 2 O 3 their use is not efficient.

The possibility of increasing the hardness (strength) nonburning-on coatings based on distensilimonita and lingosulfanata as binding by the addition of sodium aluminate and polyethylene glycol (PEG-200) was usearched. It was found that addition of these substances enhances strength for the first one temperature ranges 130–1200 ºC, and for the second one – only after drying.It is shown that for distensilimonita zircon (ZrSiO4) these substances provide high strength and as separate binders. But for paints based on Al2O3 their use is not efficient.

The article describes the features of the modification of cast iron, high chrome cast iron and steel. It is shown that the modification of cast iron complex modifier should be based on the thickness of the walls of castings, and for steel and high chrome cast iron, it is beneficial to the macro and microstructure. The data confirming the removal of transcrystallization and size reduction microand macrostructure of castings in various types of iron-carbon alloys. Experimentally proved that in the transition from columnar to equiaxed structure observed increase in the number of eutectic cells, which confirms the position that transcrystallization terminated as a result of nucleation and growth of equiaxed crystalsin the area of concentration supercooling