Nanocomposite AlCrSiN hard coatings were deposited on the cemented carbide substrates with a negative substrate bias voltage within the range of -80 to -120 V using the cathodic arc evaporation ...system. The effect of variation in the bias voltage on the coating-substrate adhesion and nanohardness was investigated. It was clear that if bias voltage increased, nanohardness increased in the range from -80 V to -120 V. The coating deposited at the bias voltage of -120 V had the highest nanohardness (37.7 ± 1.5 GPa). The samples were prepared by brushing and wet microblasting to finish a surface and prepare the required cutting edge radii for the tool life cutting tests and the coating adhesion observation. The indents after the static Mercedes indentation test were studied by scanning the electron microscope to evaluate the coating-substrate adhesion. The longer time of edge preparation with surface finishing led to a slight deterioration in the adhesion strength of the coating to the substrate. The tool wear of cemented carbide turning inserts was studied on the turning centre during the tool life cutting test. The tested workpiece material was austenitic stainless steel. The cemented carbide turning inserts with larger cutting edge radius were worn out faster during the machining. Meanwhile, the tool life increased when the cutting edge radius was smaller.
The paper deals with the issue of coating and surface finishing with edge preparation prior to the coating. Nanocomposite AlCrSiN hard coatings were deposited on WC-Co substrates with a negative ...substrate bias voltage in range of-80 to-120 V using cathodic arc evaporation system. The effect of variation in the bias voltage on the coating-substrate adhesion and nanohardness was investigated. The maximum nanohardness of coating was 37.7 ± 1.5 GPa with the good coating-substrate adhesion. Static Mercedes indentation test was performed on a Rockwell-type hardness tester. The indents were studied by scanning electron microscope to evaluate the coating-substrate adhesion. The H to E ratio that represents resistance to the plastic deformation was determined. The influence of surface roughness and time of used surface finishing methods on the coating-substrate adhesion was also investigated.
Předkládaný text se věnuje dokladům středověkého osídlení Bělidel, původně olomouckého předměstí, které bylo ve 20. letech 16. století obehnáno novou městskou hradbou a stalo se tak součástí města. ...Přináší přehled záchranných archeologických výzkumů prováděných v tomto prostoru, přičemž se podrobněji věnuje zejména výzkumu, který probíhal v souvislosti s výstavbou polyfunkčního domu č. 5 v Sokolské ulici v letech 2015 a 2016.
This paper deals with the process of cutting of nickel superalloy and selection of suitable cutting parameters for its easy and effective cutting. The experimental part proposes three exchangeable ...inserts and determines the effect of feed rate cutting parameter during machining on durability and wear of the cutting tool. Depending on selected cutting feed rate and the amount of wear of these exchangeable cutting inserts, the quality of turned surface is evaluated and height roughness parameters are determined. In closing we show our observations obtained while machining Inconel 625, determine the effect of feed rate on durability and wear of cutting inserts, evaluate and recommend practical steps, describe the mechanisms of cutting wedge wear, determine the durability of the tool and roughness of the turned surface.
This article deals with the study of the effect of cross section of the cut layer of material and its influence on the specific cutting resistance. Measurement and evaluation were carried out using ...two machined materials, according to the designation W.Nr. carbon steel 1.1191, which is a reference material for the steel grade and refractory nickel alloy 2.4856. For the purpose of the experiment, longitudinal turning technology with two interchangeable CNMG 120408 SM and CNMX 1204A2 – SM cutting inserts was chosen. According to the recommended index insert values, two different types of cutting conditions were chosen for each material so that the cross section of the chip remained the same during machining. For each material, the cutting speed was constant and the feed rate and cutting depth were changed. The main goal of the experimental work was comparison of the specific cutting resistance in dependence on different cross section of the removed layer of material. On the basis of measuring of cutting forces by dynamometer Kistler the resulting cutting force was determined and the size of the specific cutting resistance was calculated.
The paper deals with the impact of high-speed machining production methods on the integrity of component surfaces. One has to point out that cutting conditions during machining have a significant ...impact on the final properties of surface and subsurface layers of the workpiece. The conclusion summarizes and analyzes achieved results of experimental activities on stainless austenitic steel 1.4301, hardened tool steel 1.2343 and high-speed steel 1. 3344 (ASP 2023). The results of the work experimental parts demonstrate influence of cutting parameters on selected surface integrity ones, specificallystrengthening of surface and subsurface layers. The performed experiments show that microhardness of a surface layer of machined material can be influenced by suitable cutting conditions and other cutting process parameters.
The paper deals with tangential abrasive water jet (AWJ) turning of Incoloy alloy 925. The aim of the experiment was to analyze the impact of the AWJ traverse speed (1.5–9 mm/min) on the surface ...quality in terms of micro-structure formed on the created surface. The water pressure was set to 400 MPa and the spindle revolution to 34 rpm. Australian garnet (
MESH
80) was used as an abrasive component. The surfaces were visualized and qualitatively described using a laser confocal microscope. Basic roughness parameters of the surfaces (
Ra
,
Rq
,
Rz
) were measured using an optical profilometer. The presented experimental results demonstrate that the technology of abrasive water jet turning is an appropriate tool for rough machining of difficult-to-machine materials.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The contribution deals with the evaluation of the surface quality after laser cutting and determination of the influence individual input laser parameters at the whole process. There were selected ...samples for experiment made from S235JR material with the thickness 10 mm and 15 mm. There was set up values of process parameters, such as laser power, focal spot position, cutting speed and shield gas pressure. The final surface quality was measured and evaluated on the basis of the selected surface roughness parameters and material ratio. The surface quality was evaluated from point of view of defects emerging after thermal splitting according to standard ČSN EN ISO 17 658.
The paper deals with the design of a suitable cutting geometry of a tool for the machining of the Inconel 625 nickel alloy. This alloy is among the hard-to-machine refractory alloys that cause very ...rapid wear on cutting tools. Therefore, SNMG and RCMT indexable cutting insert were used to machine the alloy. The selected insert geometry should prevent notch wear and extend tool life. The alloy was machined under predetermined cutting conditions. The angle of the main edge and thus the size and nature of the wear changed with the depth of the material layer being cut. The criterion for determining a more suitable cutting geometry was the tool’s durability and the roughness of the machined surface.
The subject of the article is to compare and evaluate the stiffness of the proposed structures relative to the section of the individual rods. The study is applicable to the additive technology of ...metal production by the 316L (1.4404) by SLM method. In the SLM process the design supports serves as the transporter of the heat generated in the melting bath to the substrate, the secondary function of the structures is for support the powder layer. The article focuses on the supportive function and weight ratio. A total of 4 structures were designed in iteration with three different rod diameters. During construction, the suitability of structures for the SLM method was determined and then the samples were subjected to a mechanical tensile test and the mechanical properties evaluated. In conclusion the most appropriate structure for the supportive function was identified.
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