Studying of properties and microstructure of 30 CrMnV9 steel on wear resistance

The properties and microstructure of 30 CrMoV9 steel after its treatment with ferronickel and ferromanganese with the aim of increasing the content of nickel and manganese in steel were studied. After the trial smelting, the samples were tested in four parameters: hardness, ultimate stress limit, wear resistance, and toughness. Experimental studies have shown that changing the composition of steel with increasing the nickel content up to 0,5 – 0,7 % and manganese up to 1,5 – 1,8 % leads to increasing strength, hardness and wear resistance of steel with slight decreasing its toughness

Studying the properties of refractory products manufactured by two-stage pressing under industrial conditions

The article deals with studying the properties of refractory masses made by two-stage pressing under industrial conditions in order to increase strength and slag resistance of chamotte bricks due to increasing density by ensuring uniform porosity throughout the volume of the product. Changing porosity when firing is less significant than changing porosity when pressing, therefore, the structure of the product is corrected by the initial mass of components

Shell forming mode effect on casting quality

The paper deals with the influence of shell forming modes on some parameters of castings: the surface and internal defects. The degree of roughness and stress concentration were determined on the castings obtained under production conditions. According to the result, it was found that the use of variable pressure in the formation of the shell ensures the purity of the casting and the reduction of the stress level in the casting

Boron microadditives effect on heat resisting properties of Cr-Ni-Fe based alloy

The introducing of boron in very small amounts (0,001 – 0,02 %) improves considerably wear resistance and hardness, raises hardenability and thermal stability, it promotes grain crushing [1-3]. A preliminary analysis of the natural phases identified certain phases such as (Nb, Mo)2B. It is also possible to assume the formation of boron-containing iron-based eutectics and complex carbon-boride phases based on chromium

Chromium-nickel cast iron composition effect on properties and graphitization process

The paper considers the cast iron based on nihard-2 composition effect on the properties and process of graphitization. It is shown that changing the Cr:Si ratio equal to 2:1 leads to the development of the graphitization process, as a result of which lamellar graphite appears in the structure. Subsequent modification leads to changing the shape of the graphite into the nodular one, which leads to some decrease in hardness but increases resistance to abrasive wear by about 20-25 %

Chromium-nickel cast iron composition effect on properties and graphitization process

The paper considers the cast iron based on nihard-2 composition effect on the properties and process of graphitization. It is shown that changing the Cr:Si ratio equal to 2:1 leads to the development of the graphitization process, as a result of which lamellar graphite appears in the structure. Subsequent modification leads to changing the shape of the graphite into the nodular one, which leads to some decrease in hardness but increases resistance to abrasive wear by about 20-25 %

Studying properties of chrome cast irons modified with titanium carbide

The paper presents the results of studying hardness and wear resistance of chrome cast irons. In the study there were considered samples of cast iron of the ChN2H, ChN4H2 grades and ChN2H after treatment with titanium carbide. Titanium carbide in the amount of 1 % by weight with dispersity of 500 microns was introduced during casting into ChN2H cast iron. As a result of this treatment, the cast iron hardness and wear resistance become comparable to those of Nihard grade cast iron. Studies have shown the promise of using refractory compounds as modifiers for cast irons

Studying the properties of sand-resin molds made using a variable load

The article investigated both shell mold samples and casting samples. The castings were made of 35L steel. A scheme of the formation of a sand-tar shell form using variable pressure was presented. As can be seen from the graphs, the application of the load during the formation of the shell form significantly affects the size of the burn in the direction of its decrease. The pressure of 0,18 ... 0,25 MPa, which is defined as optimal for obtaining the forms of castings «Link», can be considered very satisfactory for the value of the burnout. As pressure increases, the rate of decline of the burn on the castings decreases. Obtained in semi-industrial conditions, the samples were investigated in the laboratory of KSTU. The strength, hardness and gas permeability of the forms were determined

Effect of reducing agent’s nature on the microstructure and certain properties of 30CrNi2Мo high-quality steel

30CrNi2Мo high-quality steel is a heat-hardenable steel. This quenched-and-tempered steel has high strength properties, sufficiently good plasticity and hardness. It is used to manufacture component parts that work in a complexloaded condition under the action of alternating loads. The classical way of heat treating for this steel is quenching with subsequent high tempering, as a result of which the structure of alloyed sorbitol type is formed. The experiment results allow us to state that killing with the new FS45A15 aluminum ferrosilicon reducing agent has a beneficial effect on the formation of a fine-grained structure

Comparative analysis of graphite inclusions in chrome cast iron structure

The paper presents the results of a quantitative metallographic analysis of graphite inclusions in the structure of chrome cast irons including cast iron of the Nihard class, as well as after treatment with titanium carbide. The ThixometPro software was used for the analysis. The shape, size, perimeter, distribution density of graphite inclusions, as well as the area occupied by the structural components and their dispersion were evaluated. It is shown that the introduction of titanium carbide has a favorable effect on the pattern of graphite inclusions and some parameters of the structure in general