Anton Panda

Accompanying phenomena in the cutting zone machinability during turning of stainless steels

The rapid development of industry is marked by the development and application of new materials with characteristics that broaden their applicable uses. Therefore, it is natural that advances in machinability attract a considerable interest even today. Precise and reliable information on the machinability of a material before it enters the machining process is a necessity and hypotheses must be tested through verification of actual methods. This article presents conclusions of machinability tests on austenitic stainless steels 1.4301 and describes appropriate parameters for the cutting zone during the process of turning. The article focuses on the analysis of selected domains through four basic some parameters of steel machinability.

Verification of Cutting Zone Machinability during the Turning of a New Austenitic Stainless Steel

In this study presents the conclusions of machinability tests on a new austenitic stainless steel X5Cr18Ni9MoTiN, which applicated in food processing industry, and describes important concurrent parameters for the cutting zone during the process of turning. The machinability of stainless steels is examined based on the cutting tests, cutting speed presented by v c-T diagrams. The effect of cutting speed are analysed by chip formation and tool wear mechanisms. Based on the cutting tests, cutting speeds of 40 to 200 m/min, feed rate of 0.04 to 1.2 mm and solid carbide indexable insert CNMG 120404-MF. Tool wear criterion, VB K value of 0.3 mm. Chip were analysed by Semi Electron Microscopy (SEM).

Evaluation of T-Vc Dependence for the most Commonly Used Cutting Tools

The main part of Standard ISO 3685 is T-vc dependence for various cutting materials. The Standard ISO 3685 contains main properties and characteristics for three most important cutting materials those are used in engineering practice. Durability is very important property of every cutting material. This property of cutting materials defined theirs life-time. The standard ISO 3685 prescribes instructions to creation of T-vc dependence for defined cutting materials. Paper describes process how to define T-vc dependence for the most commonly used, because were found deficiencies in valid standard ISO 3685.

Comprehensive Durability Identification of Ceramic Cutting Materials in Machining Process of Steel 80MoCrV4016

Specification cutting tools durability made of cutting ceramic in machining process of steel 80MoCrV4016 is very important for economics of small and medium-sized enterprises, because cutting tool durability is factor that significantly affects the budget of these enterprises. This problematic is determined for small and medium-sized manufacturers of bearings, because steel 80MoCrV4016 is most commonly used for production of bearings. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Especially for cutting ceramic is necessary to define durability dependence on available set of cutting speeds and to determine lifetime of tools made of cutting ceramic. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-vc dependence. The article describes process how to create durability dependence for cutting tools made of cutting ceramic by means of T-vc dependence in machining process of steel 80MoCrV4016.

Vibration and Experimental Comparison of Machining Process

Abrasive water jet technology is among the unconventional ways of machining. In todays modern and progressive era is often used for cutting and machining of various types of materials because of lower costs and environmental impact, as the cutting tool is water, in our case, with the addition of abrasives. Objective of the measurements was to evaluate the impact of vibration on the technological head in abrasive water jet technology in changing the selected technological parameters and the flow rate of technological head. In the given experiment, the used material - steel Hardox 500 with a thickness of 10 mm. The effort was to investigate the effects of changes in the speed rate of technological head (by speeds - 40, 200, 400 mm / min) on the size of the vibration acceleration amplitude and its frequency. Based on the measured values of vibration to the technological head create the database and from it is evaluated the data in selected softwares (LabVIEW, SignalExpress and Microsoft Excel). Findings and conclusions are formulated on the basis of graphical dependencies, envelopes frequency spectra and comparison chart of envelopes.

Roughness of Spray Coating Surface

The surface roughness is substantiated from the point of view of application of ceramic spray coatings. In the sphere of usage of ceramic spray coatings of Al2O3 as of the coating resistant to wear the roughness is substantially significant after mechanic machining—grinding. In this case it is inevitable to mention that the ceramic coatings on the basis of Al2O3 and applied by means of plasma can be machined solely by grinding. In grinding intensive cooling and use of a diamond grinding wheel is recommended.

Adhesion of Plasma Sprayed Coatings to Basic Backplate

The existing scientific experience take into consideration the influence of the following factor in formation of adhesion mechanism.

Formation of Plasma Sprayed Coating

Suitable powder for plasma spraying should possess good flow properties, should easily flow in plasma jet; the powder particles should be of spherical or similar shape and should dispose of identical dimensions defined within the range of the lower limit. In powder spraying with particles of diverse dimension the fine fractions are overheated or evaporated and coarse-grained particles dot not get heated. Important role is played by the orifice of powder feed into plasma jet. The highest effectiveness of powder heating is achieved during its feeding into the centre of the arc burning between cathode and anode in the torch. Such alternative is complicated as to structure.

Plasma Spraying Equipment

Plasma spraying equipment composing of a complex of the individual machines and devices disposing of the following functions: in plasma torch connected by unidirectional current the electric arc is ignited between wolfram cathode and cooper anode of a nozzle shape by high-frequency ignition equipment. By heating and ionization of plasma gas supplied into electric arc a high-energy plasma arc is formed by which the fed material in the form of powder is molten down, drifted, and impinges onto the machining component at high velocity.

Basic Properties of Plasma Coatings

Plasma sprayed films acquire properties differing from those of basic compact materials: oxygen and nitrogen content increases and density and plasticity decrease.