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1

The influence of hardening medium in the vacuum carburizing process on the distortion of machine elements used in the automotive industry

Pawęta S., Pietrasik R.

Journal of Achievements in Materials and Manufacturing Engineering

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2019

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Vol. 94, nr 1-2

32--40

EN

Purpose: As part of this study, the influence of the hardening medium on distortions of FineCarb® carburized rollers used in the automotive industry as elements of fuel pumps has been examined. The analysis was carried out for the process of quenching in gas at different pressure of cooling gas and quenching in oil at variable delay time of oil mixers. Design/methodology/approach: The research was carried out on real elements used in the automotive industry as elements of fuel pumps. FineCarb® vacuum carburizing technology was used in order to obtain optimal parameters of the surface layers. During quenching a variable related to the parameters of the quenching medium was introduced. For quenching in gas it was the pressure at which nitrogen was introduced into the cooling chamber, while for quenching in oil it was the time of mixers delay. The sample batch was laid out in accordance with the PPAP (Production Part Approval Process) requirements for the automotive industry. Microhardness and radial runout measurements were carried out on the samples and subjected to statistical analysis. Findings: The analysis of each hardening processes has showed that depending on the cooling medium used, different distortion values are obtained. The distortion value is significantly influenced by the parameters of the hardening process - gas pressure/oil mixers delay. With the proposed quenching parameters, there is no relationship between the location of the sample in the furnace chamber and the distortion value. The smallest hardening distortions were obtained as a result of the hardening process in gas at a gas pressure of 3 bar. Hardening in gas was characterized by the smallest scatter values of obtained results of radial runout. Research limitations/implications: Basing on the studies and analyses carried out in this work, it can be concluded that the introduction of gas quenching technology instead of oil quenching technology is justified qualitatively and economically alike. Hardening in gas was also characterized by the smallest scatter values of obtained results of radial runout. This is an extremely important technological and economic aspect, due to the cost of grinding processing. Practical implications: The automotive and aviation industries are putting ever greater demands on the quality of manufactured components while reducing costs. It requires optimization of technological processes from co-operators. In the case of hardening plants, the most important aspect is obtaining repeatable, precisely planned parameters of the carburized layer, as well as minimizing the negative phenomena that cause dimensional changes after hardening of elements. The tests allowed to determine the most effective hardening conditions in terms of obtained distortions and costs of eliminating distortions. However, the selection of the optimal parameters depends on whether the core hardness requirements are also determined. Originality/value: The conducted tests allowed to determine the most effective hardening conditions in terms of obtained distortions, costs of levelling distortions and a complete technological process for the automotive industry.

2

Selection of Optimal Thermochemical Treatment of Steel Guides of Yarn

Płonka Stanisław, Drobina Robert, Jędrzejczyk Dariusz, Postrożny Jacek

Fibres & Textiles in Eastern Europe

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2019

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Vol. 27, no. 6 (138)

27--33

EN

This paper presents a method of selection of an optimal (the best possible) thermochemical treatment of a steel guide of yarn for a ring spinning frame with the use of an optimisation procedure based on assumed criteria, and with consideration of their importance. Yarn guides for a ring spinning frame were manufactured from three brands of steel and were subjected to the following types of thermochemical treatment: 50SiCr4 steel (chrome hardening, diffusion boronising, and titanising); 41CrAlMo7 steel (nitrosulfiding and nitrogen case hardening), and C45 steel (diffusion boronizing). Unit manufacturing costs and six criteria of manufacturing quality: four parameters of surface texture (Rq, Rp, RΔq, rw), maximal hardness of the surface layer (HV0,1), and the case depth of the surface layer (gww), were taken as criteria for assessment. Values of the assessment criteria obtained from calculations and measurements were subjected to normalisation. The knowledge of experts and importance matrix B, evaluated with the use of the Saaty method (consisting in pairwise comparison of the successive criteria) were used to determine the importance of the criteria taken for the assessment. Using the Power method, eigenvalues of matrix B were found, as well as corresponding coordinates yt of the eigenvector, which are simultaneously the weights of the corresponding criteria. Normalised decisions were created in the next step by raising each component of the normalised assessments to a power equal to the corresponding weight. In the last step of the procedure, a single optimal lining-up was created comprising the smallest s-th components of the individual decisions d1, d2, ..., dm. The best variant of the thermochemical treatment was recognised as corresponding to the largest component of the optimal lining-up, which in our case is the diffusion boronizing. Key words: optimisation, thermochemical treatment, yarn guide.

PL

W pracy przedstawiono dobór optymalnej (najlepszej) obróbki cieplno-chemicznej stalowego prowadnika przędzy przędzarki obrączkowej z zastosowaniem metody postępowania optymalizacyjnego ze względu na przyjęte kryteria z uwzględnieniem ich ważności. Prowadniki przędzy przędzarki obrączkowej wykonano z trzech rodzajów stali i poddano następującym rodzajom obróbki cieplno-chemicznej: 50SiCr4 (chromowaniu, borowaniu i tytanowaniu dyfuzyjnemu), 41CrAlMo7 (azotonasiarczaniu i azotowaniu) oraz C45 (borowaniu dyfuzyjnemu). Jako kryteria oceny przyjęto jednostkowy koszt wytwarzania oraz sześć kryteriów jakości wytwórczej: cztery parametry struktury geometrycznej powierzchni (Rq, Rp, RΔq, rw) i maksymalną twardość na powierzchni HV0,1 oraz głębokość utwardzenia warstwy wierzchniej gww. Wartości kryteriów ocen uzyskane z obliczeń i pomiarów poddano normalizacji. Do określenia ważności przyjętych do oceny kryteriów wykorzystano wiedzę ekspertów oraz macierz ważności B wyznaczoną metodą Saaty’ego, polegającą na porównaniu kolejnych par kryteriów. Stosując metodę Powera znaleziono wartości własne macierzy B i odpowiadające im współrzędne yt wektora własnego, które są równocześnie wagami odpowiadających kryteriów. Następnie utworzono decyzje unormowane przez podniesienie każdego składnika ocen unormowanych do potęgi równej odpowiedniej wadze. W ostatnim etapie utworzono jedno uszeregowanie optymalne, którego składnikami są najmniejsze s-te składniki poszczególnych decyzji d1, d2, ..., dm. Wariantem najlepszym obróbki cieplno-chemicznej jest ten, któremu odpowiada największy składnik uszeregowania optymalnego, w naszym przypadku jest to borowanie dyfuzyjne.

3

Numerical analysis of the effect of nonmetallic inclusionslocation in carburized layer of 16MNCR5 steel on initiation of fatigue cracking

Lipa Sebastian

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 3

66--74

EN

This paper presents the results of a numerical analysis of the effect of the position of non-metallic inclusions in a hardened top layer in 16MnCr5 steel on the mechanism of fatigue destruction. An analysis of a hardened layer formed by thermo-chemical treatment using FineCarb® technology was conducted.Non-metallic inclusions formed by deoxidation of steel were studied; they are usually made of calcium and aluminum. Four positions of inclusions in the hardened layer were tested: under the layer, in the middle part of the layer, under the surface and on the border of two sublayers. The results of the FEM analysis were treated as a qualitative analysis. A map of plastic strains around the inclusion under study was observed. The appearance of plastic strains in the area under analysis signaledthe initiation of a fatigue crack. It was observed that the mechanism of destruction depends largely on the distribution of stress in the top layer and on the place where the inclusion is anchored in the layer. Inclusions under the layer were found to be the main cause of the loss of the structural continuity, which explains the most frequent cases of the initiation of fatigue cracks.

4

Proecological use of agrobiomass

Wawrzyniak A., Zbytek Z.

Journal of Research and Applications in Agricultural Engineering

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2015

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Vol. 60, nr 4

120--124

EN

The growing sector of agricultural biogas plants in Poland and Europe is facing a serious problem of managing digestate. In Europe there are currently about 14,500 biogas plants. The fact that both the EU Waste Directive and the Polish Act on Waste qualifying digestate as waste does not make the situation any easier. The simplest method of developing digestate is to directly spread it on fields. The implementation of this method is impeded by limiting the areas of cultivation due to the high content of organic nitrogen and odor emission. The growth in the number of biogas plants will be associated with the increase in the digestate disposal problem. Alternative methods of fertilization involve the separation into solid fractions and liquid fractions. After composting, solid fractions may be used as fertilizer, sometimes as solid granulation. The use of solid fractions of digestate for energy purposes involves using them as feedstock for pellets and briquettes production. The gasification and carbonization are two of several possible methods of thermochemical treatment of biomass.

PL

Rozwijający się sektor biogazowni rolniczych w Polsce i Europie boryka się z poważnym problemem zagospodarowania pofermentu. W Europie pracuje obecnie ok. 14 500 instalacji biogazowych. Wraz ze wzrostem instalacji biogazowych problem zagospodarowania pofermentu bedzie narastał. W świetle unijnej dyrektywy o odpadach oraz polskiej ustawy o odpadach poferment kwalifikowany jest jako odpad. Najprostszą metodą zagospodarowania pofermentu jest bezpośrednie rozprowadzanie go po polach. Przeszkodę w realizacji tej metody aplikacji pofermentu stanowi ograniczenie terenów uprawowych ze względu na dużą zawartość azotu organicznego, ale także emisja odorów. Alternatywnymi metodami zagospodarowania pofermentu jest separacja na frakcję stałą i ciekłą. Frakcja stała po poddaniu do kompostowania materiałów organicznych nadaje się do użycia jako nawóz, czasami stosuje się też granulacje osadu. Energetyczne wykorzystanie pofermentu sprowadza się do wykorzystania osadu jako wsadu do produkcji peletów i brykietów. Innymi metodami zagospodarowania pofermentu sa gazyfikacja i karbonizacja - wybrane z kilku możliwych sposobów obróbki termochemicznej biomasy.

5

Precise formation the phase composition and the thickness of nitrided layers

Ratajski J., Olik R., Suszko T., Dobrodziej J., Michalski J., Gilewicz A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

675-689

EN

Purpose: The article presents the application of the duplex technology (nitriding plus PVD) to modification of the surface of pressure casting dies made of steel WCL (EN: X37CrMoV51). In this technology, there are clearly defined expectations regarding the properties of the surface layer of the dies obtained in the nitriding process. The main part of the article is presentation a complex system of designing, in-situ visualization and control of the gas nitriding process. Design/methodology/approach: In the conception of computer designing, analytical mathematical models and artificial intelligence methods were used. Findings: As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers. Practical implications: Computer procedures make it possible to combine, in the duration of the process, the registered voltage and time runs with the models of the process. Originality/value: For in-situ visualization of the growth of the nitrided layer, computer procedures were developed which make use of the results of the correlations of direct and differential voltage and time runs of the process result sensor (magnetic sensor), with the proper layer growth stage.

6

On low temperature ion nitriding of austenitic stainless steel AISI 316

Toshkov V., Russev R., Madjarov T., Russeva E.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 1

71-74

EN

Purpose: The purpose of this paper is to discuss some problems concerning the extremely high values of the nitride layer hardness and the features of so called S-phase which are formed after low-temperature ion nitriding of high-alloyed austenitic (austenitic-ferritic) steels. Design/methodology/approach: The investigations are performed mainly by using of ray diffraction method after ion nitrided 316 (AISI) steel. Findings: As a result of the work some data, concerning the structure and substructure, the phase composition of the S-phase, crystal lattice, the broadening of diffraction reflexes, mechanism of transformation of gamma'- phase into S-phase, its high hardness etc. of the nitrided layer are obtained. It could be concluded that S-phase could be classified as a modified gamma'-phase. The extremely high values of the hardness could be explained by the high nitrogen concentration in the solid solution and by the presence of increased density of the defects in the austenitic volume, which is transformed in the new S-phase. Research limitations/implications: The potencionstatic investigations of the electrochemical properties of the nitriding probes, performed by us, confirmed the data, obtained by the literature, but this problem will be discussed in some of the next publications. Originality/value: The high micro- and macro-deformations of the lattice of S-phase could be explained by the considerable registered expansions and the angle replacements of the slope (psi) on the ray diffraction maxima. The registered macro deformations could reach immense values, in the range of (1.4 - 2.1)x10-2, which corresponds to macro deformations around 1900 - 2300 MPa (if we accept, for the austenite, the usual module of elasticity of 2.1x105 MPa). For such final decision it is necessary to obtain also some other confirmation facts.

7

Influence of preparing of GFR recyclates on the properties of polyester matrix compsites

Myalski J., Śleziona J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

163--166

EN

Purpose: The purpose of this project was to estimate the possibility of using polyester-glass fiber recyclate as a reinforced component of polymer matrix in composites. This kind of mechanical recycling can be use as one of the way of polymer composites utilization. Recyclates prepared from GFP - polyester resin reinforced glass filaments. Design/methodology/approach: Recyclate obtained after grinding was a mixture of cured polyester resin particles and glass fibers. Two different groups of recyclates have been obtaining after separation. First group of recyclate was used to prepare of stratified laminates. Second group of recyclate was used as a filler of polymer matrix. Findings: The results of the investigation have shown that using of polymer composites wastes as a filler, leads to decreasing of the flexural and impact strength. However obtained material had a bending strength comparable with standard material. The results of mechanical properties have been prove that change of properties depends on the size of fraction recyclate. Fraction containing the particles in fibrous shape better influence on that mechanical properties of laminates. The results of the investigation have shown that using of polimer composites wastes as a filler materials (core), leads to decreasing of the properties in bending and impact tests. It has been shown that content of the recyclate has significant influence on studied mechanical properties. Practical implications: The results of the investigation have shown that using of polymer composites wastes as a filler, leads to decreasing of the properties in bending and impact tests. Surface treatment of recyclates has been shown that bending strength between matrix and recyclates improve. Originality/value: The results of the investigations allow to confirm, that the polymer composites waste can be used as a filler polymer matrix in production of new composites, being also one of the way of utilization of composite with thermosetting matrix.

8

Komputerowy system sterowania i wizualizacji procesami F-A/O-D w wersji laboratoryjnej.

Jasiński J., Jeziorski L., Frączek T., Torbus R., Chrzęstek P., Babul T., Nakonieczny A., Obuchowicz Z., Orzechowski D.

Inżynieria Materiałowa

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2002

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R. XXIII, nr 5

344-346

PL

Celem artykułu jest opis komputerowego systemu sterowania procesami obróbki cieplnej i cieplno-chemicznej w złożu fluidalnym (F-A/O-D). System ten został wykonany dla Instytutu Inżynierii Materiałowej Politechniki Częstochowskiej. W artykule tym opisano urządzenia do prowadzenia procesu (F-A/O-D): piece fluidyzacyjne PFL-1, PFL-2, PFL-3, oraz wanny chłodzące WCH-1, WCH-2. Zawiera on również przykładowe okna wizualizacyjne pieca PFL-1. Praca ta została wykonana w ramach projektu celowego 7 T08C 059 2000C/4941[1].

EN

The purpose of this paper is description computer control system of the process heat treatment and thermochemical treatment in a fluidized bed (F-A/O-D). The system controls the temperature, flow rate of gases and composition of atmosphere. Some fluidized-bed furnaces: PFL-1 (for preheating of details) and PFL-2 (for austenitizing and carbonitriding), PFL-3 for nitriding and two cooling bath WCH-1, WCH-2 are presented. The visualization window for fluidized-bed furnace - PFL-1 is shown.