Effect of iron content and laser hardening on the fractography of high-frequency fatigue fractures in AK8M3 alloy samples

The equipment and techniques of accelerated fatigue tests allowed to determine an optimum iron content in the secondary aluminium alloy AK8M3 strengthened by laser processing

Recycling of stainless steel bar scrap by radial-shear rolling to obtain a gradient ultrafine-grained structure

The paper presents the results of the conducted experiments confirmed not only the possibility of processing bar scrap from stainless metals to produce a marketable product, but also confirmed the possibility of obtaining highquality bars with a gradient fine-grained structure and an increased level of mechanical properties. In the course of the research conducted on deformed bar scrap in the form of pins from 12X18N9T austenitic stainless steel at the radial-shear rolling mill the microstructure of two different types was obtained: on the periphery - equiaxed ultrafine- grained structure with a grain size of 0,4 – 0,6 μm; in the axial zone - oriented striped texture. This discrepancy in the structure of the peripheral and axial zones, together with the results of microhardness measuring across the cross section of samples with a total degree of deformation of 44,4 %, indicates the gradient nature of the formed microstructure

Effect of surface modification of 5KHV2S steel on the mechanism and intensity of contact wear

The paper presents the experimental study of the contact wear of 5KHV2S steel after surface modification. It is shown that without hardening of the surface layer, 5KHV2S steel is capable of satisfactory operation when a pulsating contact stress of 970 MPa is applied. The most qualitative type of surface modification is the hardening of the surface layer by nitrocementation carried out before quenching and tempering. The proposed technology of volumetric- surface hardening, including forging in a new forging tool, chemical-thermal treatment, quenching and lowtemperature tempering, provided the possibility of increasing the pulsating contact stress to 1 100 MPa, and the operation period during the first 13 000 loading cycles gives wear of the working surface no more than 0,1 mm

Wear of 16MnCrS5 steel surface layers in the pulsing contact loads

Approaches to actualizing the use of modern alloy steels that are in demand in the Eurasian technological space are proposed. According to the criterion of resistance to contact fatigue, quantitative indicators of wear of the surfacehardened layers of steel 16MnCrS5 were revealed. With the contact stress amplitude up to 950 MPa, the composite material of carbonized and nitrocemented layers is characterized by a period of high resistance with minimal manifestations of structural hardening by the mechanism of softening of the material. The obtained composite material with carbonized and nitrocemented layers is characterized by a period of high resistance up to 15 000 cycles

On the mechanism of structure formation of dead-hard carbon phase in the nanocomposite system of Fe - C for woodworking tools

In the article hypothesized that the formation of particulate gray superhardness carbon phase occurs through a stage of transition nanocarbon component of the mixture into a liquid state under highsintering method of consolidation