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1

Ultrasonic Testing of Vermicular Cast Iron Microstructure

Tupaj M., Orłowicz A. W., Mróz M., Kupiec B., Pająk D., Kawiński M.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

36--40

EN

The paper presents results of a study on the effect of passage of time on magnesium content in iron alloys and the effect of magnesium content on the number of vermicular graphite precipitations per unit surface area and value of the longitudinal ultrasonic wave velocity for two different vermicularization methods. The study was carried out with the use of inspection bar castings. For specific production conditions, it has been found that in case of application of both the cored wire injection method and the method of pouring liquid metal over magnesium master alloy on ladle bottom, the satisfactory level of magnesium content in the bottom-pour ladle, for which it was still possible to obtain castings with vermicular graphite, was 0.018% Mg. In case of the cored wire injection method, the “time window” available to a pouring station at which castings of vermicular cast iron are expected to be obtained, was about 5 minutes. This corresponds to the longitudinal ultrasonic wave velocity values exceeding 5500 m/s and the number of graphite precipitations per unit surface area above 320 mm-2. In case of the master alloy method, the respective “time window” allowing to obtain castings of vermicular cast iron was only about 3 minutes long. This corresponds to the longitudinal ultrasonic wave velocity value above 5400 m/s and the number of graphite precipitations per unit surface area above 380 mm-2.

2

Ductile Cast Iron Microstructure Adjustment by Means of Heat Treatment

Mróz M., Orłowicz A. W., Tupaj M., Kupiec B., Kawiński M.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

37--40

EN

The study presented in this paper concerned the possibility to apply a heat treatment process to ductile cast-iron thin-walled castings in order to remove excessive quantities of pearlite and eutectic cementite precipitates and thus meet the customer’s requirements. After determining the rates of heating a casting up to and cooling down from 900°C feasible in the used production heat treatment furnace (v_h = 300°C/h and v_c = 200°C/h, respectively), dilatometric tests were carried out to evaluate temperatures T_gr, TAc₁ ^start, TAc₁ ^{, TAr₁ ^start, and TAr₁ ^end. The newly acquired knowledge was the base on which conditions for a single-step ferritizing heat treatment securing disintegration of pearlite were developed as well as those of a two-step ferritization process guaranteeing complete disintegration of cementite and arriving at the required ferrite and pearlite content. A purely ferritic matrix and hardness of 119 HB was secured by the treatment scheme: 920°C for 2 hours / v_c = 60°C/h / 720°C for 4 hours. A matrix containing 20–45% of pearlite and hardness of 180–182 HB was obtained by applying: 920°C for 2 hours or 4 hours / v_c = 200°C/h to 650°C / ambient air.}

3

Odporność na korozję powłoki NiCrFeSi obciążonej cieplnie w atmosferze powietrza i w środowisku siarki

Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Kupiec B., Radoń M., Jacek M.

Przegląd Spawalnictwa

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2018

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R. 90, nr 4

73--75

PL

Praca dotyczy natryskiwanej plazmowo powłoki NiCrFeSi na podłoże ze stali kotłowej (P 250GH). Powłokę obciążano cieplnie w atmosferze powietrza i w środowisku siarki. Obciążenie cieplne wynosiło 2000 cykli. Jeden cykl obejmował: nagrzewanie do temperatury 560 °C i wygrzewanie w tej temperaturze w czasie 3 minut, chłodzenie do temperatury 300 °C, nagrzewanie do 560 °C i wygrzewanie w tej temperaturze w czasie 1,5 minuty oraz chłodzenie do temperatury 150 °C. Efektem obciążeń cieplnych było zmniejszenie grubości powłoki o 39 μm. Stwierdzono, że siarka dyfundowała w warstwę przypowierzchniową. Tworzące się produkty jej reakcji z niklem i chromem sprzyjały wykruszaniu się składników tej warstwy, które następnie ulegały utlenianiu.

EN

The paper deals with a NiCrFeSi coating plasma-sprayed on a boiler steel (P 250GH) substrate. The coating was heat-loaded in atmosphere of air and in sulfur environment. The heat load comprised 2000 cycles, whereas each of the cycles included: heating up to 560 °C and soaking at the temperature for 3 minutes; cooling down to 300 °C and soaking at the temperature for 1.5 minutes; and cooling down to 150 °C. As a result of such thermal cycling, thickness of the coating was reduced by 39 μm. It has been found that sulfur had diffused into the superficial layer. The occurring products of sulfur reacting with chromium and nickel contributed to spalling of components of the layer which subsequently were subject to oxidation.

4

Możliwości poprawy odporności na erozję kawitacyjną staliwnych zaworów hydraulicznych

Orłowicz A.W., Mróz M., Radoń M., Kupiec B., Jacek M., Sobolewska P.

Przegląd Spawalnictwa

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2018

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R. 90, nr 4

56--58

PL

Powierzchnie wewnętrzne gniazd uszczelniająco-odwadniających zaworów hydraulicznych są zwykle odwzorowane przez wkładki wykonane ze stopu miedzi, które są mechanicznie połączone z korpusem zaworu. Wskutek gwałtownych zmian ciśnienia wody, wkładki te mogą ulec poluzowaniu, co powoduje nieszczelność zaworów. W pracy zaproponowano nowe rozwiązanie poprzez zastosowanie powłoki natryskiwanej plazmowo. Przedstawiono wyniki badań odporności na erozję kawitacyjną dotychczas stosowanego materiału wkładki ze stopu CuZn39Pb2Al oraz materiału powłoki wykonanej z proszku WCCoCr 86104. Oceniono strukturę geometryczną powierzchni kraterów kawitacyjnych (parametr Rt). Stwierdzono, że powłoka naniesiona plazmowo charakteryzuje się zdecydowanie wyższą odpornością na erozję kawitacyjną, w porównaniu do dotychczas stosowanego materiału wkładki ze stopu CuZn39Pb2Al.

EN

Inner surfaces of sealing-draining seats in hydraulic valves are usually reproduced by inserts made of a copper alloy joined mechanically with valve housing. As a result of sudden variations in water pressure, they can be subject to loosening which leads to deterioration of valve tightness. In the paper, a new solution is proposed for finishing surfaces of valve seats by application of a plasma-sprayed coating. The solution is validated by results of cavitation erosion resistance test performed for both the CuZn39Pb2Al alloy used earlier for the inserts and the material of coating made of WCCoCr 86104 powder. The resistance assessment was based on geometrical structure of cavitation craters (parameter Rt). It has been found that the plasma-sprayed coating demonstrated a definitely higher resistance to cavitation erosion compared to CuZn39Pb2Al alloy used earlier for valve seat inserts.

5

Surface Hardening of Nodular Cast Iron by GTAW Remelting

Orłowicz A. W., Trytek A., Korzeniowski M., Kupiec B.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

53--58

EN

The study reported in this paper was aimed at establishing the effect of values of parameters characterizing the process of superficial remelting of a nodular iron casting on the quantity of introduced heat, geometry of remeltings as well as parameter λ and hardness of cementite eutectic. The remelting process was carried out using GTAW method, at electric arc length of 3 mm in argon atmosphere, welding current intensities I = 50, 130, 210, and 300 A, and electric arc scanning speeds vs = 200, 400, and 800 mm/min. The measurements included estimation of the quantity of heat introduced to the casting in the electric arc-induced remelting process with the use of flow calorimeter. Widths and depths of remetlings were assessed with the use of metallographic method. As a result of fast solidification, cementite eutectic was obtained in remelted material in which, in the course of cooling down to ambient temperature, austenite was subject to partial transformation into martensite. To characterize the cementite eutectic, value of the structural parameter λ was assessed. Values of the parameter were similar for areas of occurrence of both fibrous and laminated eutectic. Remeltings were examined at half of their depths. Micro-hardness measurements were taken in the same areas. The established quantitative relationships may prove to be useful in practice for the purpose of predicting values of parameter λ and hardness of remeltings in studies aimed at improving resistance of cast-iron castings to abrasive wear.

6

A Possibility to Improve Resistance of Cast-iron Wood Chip Fine Grinder Liners to Abrasive Wear

Orłowicz A. W., Mróz M., Tupaj M., Kupiec B., Jacek M., Radoń M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

35--38

EN

The paper deals with the issue of potential for improvement of resistance of wood chip fine grinders to abrasive wear by providing them with WCCoCr coating applied with the use of atmospheric plasma spraying (APS). The study focused on establishing parameters of the technological process of spraying a 250–270 μm thick coating onto surface of ductile cast iron castings used to date as grinder linings. The presented data include results of microstructure examination, chemical composition analysis, HV hardness measurements, and scratch tests for both previous and new variant of linings. The obtained scratch test results indicate that the material of the coating is characterized with definitely lower susceptibility to scratching. The scratch made on coating was 75–84 μm wide and 7.2–8.2 μm deep, while the scratch on cast iron was distinctly wider (200–220 μm) and deeper (8.5–12.8 μm). In case of cast iron, the range of variability in scratch width and depth was definitely larger. This can be explained with large difference in hardness of individual components of microstructure of cast iron and significantly larger plastic deformation of cast iron compared to the coating revealed in the course of indenter motion over surfaces of the two materials. It has been found that application of WCCoCr coating offered better resistance of lining surfaces to scratching which can be considered a rationale for undertaking in-service tests.

7

A Possibility to Improve Resistance of Cast-iron Hydraulic Valves to Cavitation Wear

Orłowicz A. W., Tupaj M., Mróz M., Kupiec B., Jacek M., Radoń M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

31--34

EN

A common problem encountered in hydraulic valves is a progressing deterioration of tightness of their water flow cutting-off seats. The seats are provided usually with a copper-alloy insert joined mechanically with cast-iron valve housing. The problem of unreliability of such joints can be solved by providing surface of the seat with a coating, deposited with the use of HVOF method and resistant to abrasive and cavitation wear. The tests were carried out for a sealing-draining seat insert made of CuZn39Pb2Al brass used to date and a specimen taken from the cast-iron valve housing which was the substrate for a plasma-sprayed coating of powder containing 86.1% Cr, 7.2% Ni, and 6.7% C. The coating, 345 ± 15 μm thick, was characterized with good quality of bonding with cast-iron substrate and high compactness of the material. The cavitation wear test on materials used in the study were carried out with the use of Vibra-Cell ultrasonic liquid processor (Sonics) equipped with a piezoelectric probe operating at the frequency of 20 kHz. Based on profilograms taken along a line crossing centers of cavitation craters, measurements of the height parameter Rt, and microscopic observations of surfaces it has been found that the coating plasma-sprayed onto substrate of nodular cast iron demonstrated higher resistance to cavitation compared to copper-alloy inserts used so far in cast-iron hydraulic valves. Cavitation craters on the material used typically for valve seats to date were more distinctly outlined and deeper compared to craters observed on the coating. Larger were also sizes of local tear-outs which resulted in larger difference between the peaks line and the valleys line.

8

The Effect of Carbides Orientation in NC11 Steel on Scratch Susceptibility of Die Inserts Used to Press Stampings for Refractory Shapes

Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Kupiec B., Korzeniowski M., Sondej K., Kozak L.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 2

95--98

EN

NC11 steel, in view of the specificity of its manufacturing process, is characterised with band-like orientation of carbides. Depending on the direction of cutting the material for the inserts out of commercially available steel products, carbide bands can be oriented in parallel or perpendicularly to the direction in which aggregate grains move in the process of pressing stampings. It has been found that in case of scratches made in direction perpendicular to carbide bands, depth of the scratches is less than this observed when scratches are made in direction coinciding with prevailing orientation of carbide precipitates.

9

Determination of Unit Pressure Force in Material Volume in the Course of Refractory Stamping Press Moulding

Orłowicz A. W., Mróz M., Cisek Z., Tupaj M., Trytek A., Kupiec B., Korzeniowski M., Sondej K., Kozak L.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 2

61--68

EN

The paper presents results of assessment of the unit pressure force within the refractory material volume in the course press-moulding of stampings for refractory precast shapes. The force was evaluated with the use of physical simulation of deformation undergone by lead balls placed in the raw refractory mass subjected to pressing in a metal die. To determine the value of unit pressure force applied to the aggregate grains in the course of stamping press-moulding, physical model of deformation of a sphere induced by the uniaxial stress state was used.

10

An Assessment of Appropriateness of the Choice of Parameters for Refractory Stampings Fabrication Process

Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Kupiec B., Korzeniowski M., Pająk D., Sondej K., Kozak L.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 2

55--60

EN

The paper presents results of an analysis of material density distribution in stampings press-moulded in metal dies from raw refractory materials based on alumina-magnesia-carbon aggregate. The stampings, fabricated on LAEIS HPF 1250 pressing machine, are blanks from which refractory precast shapes are manufactured by means of drying and firing. Samples for material density evaluation were cut out from test stampings with the use of diamond-reinforced disc. Density of the material was determined in thirteen layers of stampings denoted with letters A through M.

11

Effect of the Viscoelastic Properties of Treated Steel on the Rheology and Dissipative Properties of Frictional Contact

Shevelya V., Sokolan J., Kupiec B., Korenivskyi M.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1 spec.

193--198

EN

Effect of the tempering temperature of hardened carbon steel and conformable structural changes on physical-mechanical properties and tribological characteristics during dry sliding friction was researched. It is shown, that relation between adhesive and deformational components of the frictional force depends on acquired during tempering viscoelastic properties that influence on mechanism of the contact interaction and dissipative processes. Viscoelastic properties are detected by two basic rheological parameters: modulus of elasticity and damping capacity, with which the viscoelastic coefficient is connected. The theoretical analysis of dissipative properties of the viscoelastic frictional contact dissected subject to the structure of tempered steel on the base of examined standard rheological models.

12

Corrosion of AlSi 304L Austenitic Stainless Steel in Non-Stationary Aqueous HCl + NaCl Solution

Opiekun Z. A., Orłowicz A. W., Kupiec B.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1 spec.

165--168

EN

The paper describes the process of stress corrosion in a Ø50 mm rod made of AISI 304L austenitic chromium-nickel steel. Discs cut off from the steel rod were moved at a speed of 1.25 m/s for a test period of 408 h in a corrosive environment of aqueous solution containing 3% HCl and 8.6 g NaCl at room temperature. It was found that deepest cracks and irregular pitting occurred locally in areas of microstructure containing grains of hard lamellar &alpha' martensite and along boundaries between filamentary delta ferrite (Feδ) precipitates and &alpha′ phase. The corrosion developed in a trans-crystalline manner with branches propagating along boundaries of lamellar &alpha′ phase grains.

13

Poszukiwanie układu modelowego w opracowywaniu nowych produktów spożywczych

Kołczak T., Kupiec B.

Przemysł Spożywczy

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2004

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T. 58, nr 3

44-46

PL

Opisano metody poszukiwania związków pomiędzy wynikami z analiz fizykochemicznych i instrumentalnych produktów a oceną sensoryczną i preferencjami konsumentów w procesie ONP. Wymieniono i omówiono dostępne oprogramowania i możliwości ich wykorzystania w procesie ONP. Produktem modelowym byt ser typu Cheddar.

EN

The methods for seeking the relationships hetween the results of physico-chemical and instrumental analyses of the products and sensory evaluation and the consumers' preferences in ONP process were described. The available software and the possibilities of its application in ONP process were mentioned and discussed. Cheddar-type cheese was considered as the model product.

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Analiza sensoryczna w opracowywaniu nowych produktów spożywczych

Kołczak T., Kupiec B.

Przemysł Spożywczy

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2004

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T. 58, nr 1

32-33

PL

Analiza sensoryczna jest podstawowym narzędziem w procesie ONP (Opracowywanie Nowych Produktów). W analizie sensorycznej powinny być zrealizowane dwa podstawowe cele: opis produktu pod względem intensywności wyróżników sensorycznych oraz wyznaczenie poziomu akceptacji (preferencji) projektowanych nowych produktów. Opisano metody opisowej oceny sensorycznej oraz metody oceny preferencji konsumenckiej. Produktem modelowym był ser typu Cheddar.

EN

The sensory analysis is a basic tool In New Products Development (NPD) process. Two aims should be performer by sensory analysis: description of a product In relation to intensity of sensory parameters and assessment of acceptation (preference). Assessment methods are also described. The model product was Cheddar cheese.