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Pomiar rozkładu temperatury w strefie skrawania za pomocą kamery termowizyjnej

100%

Kiszka P. , Grzesik W. , Rech J.

2015

tom R. 88, nr 3

197--200

Przedstawiono wyniki pomiaru rozkładu temperatury w strefie skrawania uzyskane za pomocą kamery termowizyjnej podczas toczenia ortogonalnego żeliwa sferoidalnego (perlityczno-ferrytycznego) ostrzami z ceramiki azotkowej i CBN. Program eksperymentu obejmował pomiar średniej i maksymalnej temperatury kontaktowej oraz uzyskanie kolorowych termogramów.

Reported are the results of temperature distribution measurements in the cutting zone carried out by means of a thermal image camera during orthogonal turning of the pearlitic-ferritic (PF) spheroidal cast iron (EN-GJS-500-7 grade) using CBN and nitride ceramic tools. The experiment consisted of measurements of the average and the maximum cutting contact temperatures and color thermal photographs.

Characterization of Friction Properties During Machining of Various Stainless Steels

100%

Naisson P. , Rech J. , Paris H.

tom Vol. 61, iss. 4

239--248

Many issues in machining are related to interface characteristics, such as the friction coefficient, adhesive layer, or heat transfer coefficient. A specially designed tribometer is used to quantify these contact parameters in the case of four stainless steels (three austenite grade with controlled composition and an austenito-ferritic one). The sensitivity to sliding velocity and coatings is investigated. It is highlighted that the contact pressure effect is limited compared with the influence of sliding speed. Moreover, tool damage can also be explained by local phenomena exhibited by the tribometer, such as adhesion layer or thermal aspects, which are critical in case of stainless steels.

Surface integrity on hardened steel parts produced by hybrid machining sequences

100%

Grzesik W. , Rech J. , Wanat T.

tom Vol. 31, nr 2

654-661

Purpose: Of this paper is the investigation of surface integrity generated in hard turning and subsequent finish abrasive machining. The primary reason for undertaking this problem was insufficient magnitude of compressive residual stresses after hard turning which determines the fatigue resistance of highly loaded transmission parts. Design/methodology/approach: Employed uses 2D and 3D description of the surface roughness/surface microstreometry and the X-ray diffraction method for measurements of residual stresses. The main scope of this research program is to record the relevant changes of surface layer features resulting from the application of finish abrasive passes. Findings: Can be distinguished into two groups. First, finish belt grinding produces the residual stresses with the maximum value of-1000 MPa, which is satisfactory for improving fatigue life. Second, the bearing properties improve due to displaying negative values of the skew. Research limitations/implications: Deal with the identification range of 3D roughness parameters and the lack of modern equipment for robust measurements of residual stresses: Future research should be focused on the stronger correlation between technological and exploitation properties of the surfaces produced by hard and abrasive technologies. However, it needs more detailed inputs from automotive industry. Practical implications: Are related to the automotive industry, especially to manufactures of such transmission elements as synchronizing cones/planes on gear wheels. The sequences of new hybrid machining processes are partly verified in terms of industry needs (machining conditions, machine tools, special equipment, cutting and abrasive tools). Originality/value: Of this industry-oriented contribution is based on the aggregating hard cutting and abrasive machining processes. The practical value of the paper is that it proposes a very beneficial machining process for highly loaded hardened parts.