Studying the chrome-nickel cast iron structure and properties after modification on industrial samples

The paper presents the results of studying the structure and properties of chrome-nickel cast iron samples obtained under production conditions. Cast iron with a given ratio of silicon and chromium smelted in an industrial arc furnace was treated with titanium carbide followed by modification with a complex modifier containing (Scanning electron microscope). As a result of the composition adjustment and appropriate processing, a mixed structure was formed represented by an austenite-ledeburite matrix, iron, chromium and titanium carbides and a small amount of free graphite, both lamellar and spherical. This structure is characterized by higher wear resistance and impact resistance compared to Nihard-2 but at the same time it shows lower hardness

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 chrome-nickel cast iron structure and properties after modification on industrial samples

The paper presents the results of studying the structure and properties of chrome-nickel cast iron samples obtained under production conditions. Cast iron with a given ratio of silicon and chromium smelted in an industrial arc furnace was treated with titanium carbide followed by modification with a complex modifier containing (Scanning electron microscope). As a result of the composition adjustment and appropriate processing, a mixed structure was formed represented by an austenite-ledeburite matrix, iron, chromium and titanium carbides and a small amount of free graphite, both lamellar and spherical. This structure is characterized by higher wear resistance and impact resistance compared to Nihard-2 but at the same time it shows lower hardness

Nanomodifier effect on structure and properties changes of heat-treatable steel

The paper considers the effect of titanium carbide nanopowder (hereinafter referred to as the nanopowder material, NPM) on the structure and properties of medium-carbon heat-treatable steel containing vanadium, niobium, molybdenum and chromium. The titanium carbide nanopowder with dispersion of 80-90 nm in the amount of 0,08 % was introduced into steel before casting. After heat treatment, the prototypes were tested for hardness and wear resistance. The results show that in the experimental samples these properties are improved, which is associated with changes in the structure. The metallographic analysis of the structure (interstitial phases) was performed using ThixometPro software (Russia). In the analysis such parameters as the average size and the perimeter of interstitial phases, their shape and total relative occupied area were estimated. The results show that introducing the NPM leads to decreasing the size of interstitial phases and increasing the sphericity of the shape. Such structural changes increase hardness and wear resistance

Studying properties and structure of antifriction cast iron additionally alloyed with titanium

This article presents data on the study of the properties and structure of antifriction cast iron additionally alloyed with titanium. On the basis of experimental data favorable effect of titanium microalloying in an amount of 0,25 % on the performance properties of antifriction gray cast iron AChS-2 is shown: sliding factor increases almost 1,5 times, shape, and size of craters after shock-cycling impact are improved. This improvement in properties suggests an increase in structural strength and service life of parts made of the experimental alloy. The alloy was smelted in an industrial furnace

Effect of inoculant introducing on improving ingot structure

The paper deals with the inoculant–freigrator effect on some parameters of the structure: grain size and contamination index. The “beads” extracted from steelmaking slags were used as the inoculant. The effect of the fractional composition and the number of introduced “beads” were investigated. The “beads” were preliminarily crushed to the fraction of 100 – 1 500 μm and were introduced into the melt in the amount of 0,5 – 1,5 % by mass. It was established that the introduction of the “beads” of the fraction of 500 – 600 microns in the amount of 1 – 1,5 % as the inoculant contributed to the grinding of grain, reduced the tendency to segregation and dendre formation

Studying the properties of shell molds manufactured under industrial conditions using unsteady-state pressure

The article deals with studying the properties of shell molds. A series of tests was carried out using ground broken chamotte bricks. The tests show that the most durable mold is obtained using the ratio of quartz sand and fireclay chips in approximately the same proportions. There were used different base pressures during shaping, the most rational was recognized 0,2 MPa. A field study showed an exponential dependence of density on base pressure. The pressure of 0,25 MPa allows obtaining dense molds that withstand transportation between workshops. The dependences of the sand density on forging pressure, bending strength on the applied static pressure, gas permeability of the sand-resin shell depending on the duration of the shaping, gas permeability of the mold on the sintering time and gas permeability of the mold on the sintering temperature are considered

Studying the effect of boron on heat-resistance properties of Ni-Cr alloys

Heat-resistant alloys based on Ni-Cr system are widely used as alloys for the manufacture of rings, fasteners, turbine disks and other parts operating at temperatures up to 750 °C. To improve the properties of these alloys, these are additionally doped by Al, Ti, Mo and other elements