The Influence of Pearlite Present in the Microstructure of GX120MnCr13 Cast Steel on Wear Resistance

The article presents the results of metallographic and tribological tests on GX120MnCr13 cast steel that was previously subjected to heat treatment (including solution treatment from 1100°C and isothermal holding at 250, 400, and 600°C for 100 hours). The temperatures of the isothermal holding process were selected in order to reflect the possible working conditions of the cast elements that can be made of this cast steel. Wear tests were carried out under dry friction conditions using the ball-on-disc method using a ZrO2 ball as a counter-sample. The tests were carried out with a load of 5 N. The influence of the long-term isothermal holding process on the microstructure of the tested cast steel was analysed by light and scanning microscopy; however, abrasion marks were also examined using a confocal microscope. Based on the tests conducted, it was found that in the microstructures of the sample after solution treatment and samples that were held in isothermal condition at 250 and 400°C, the grain boundary areas were enriched in Mn and Cr compared to the areas inside the grains. Pearlite appeared in the sample that was heated (or held in isothermal holding) at 600°C; its share reached 41.6%. The presence of pearlite in the austenitic matrix increased the hardness to 351.4 HV 10. The hardness of the remaining tested samples was within a range of 221.8–229.1 HV 10. Increasing the hardness of the tested cast steel directly resulted in a reduction in the degree of wear as well as the volume, area, and width of the abrasion marks. A microscopic analysis of the wear marks showed that the dominant process of the abrasive wear of the tested friction pair was the detachment and displacement of the tested material through the indentation as a result of the cyclical impact of the counter-sample

Fracture Energy and Fracture Morphology after Three-Point Bending Test of Welded Joints Made of Cast Steel Designed for Use in Power Sector, with and without the Addition of Rare Earth Metals

The paper reports the three-point bending test results of welded joints. The joints were made of chromium-molybdenum cast steel designed for the use at elevated temperatures. TIG (tungsten inert gas) welding technique was used. The fracture energy for particular joint zones and the stretch zone width (SZW) under the notch bottom were determined in a qualitative fracture toughness assessment. Fracture surface morphology was analyzed. The stretch zone measurement indicated a qualitative relationship between its width and the values of fracture energy. The results confirmed the influence of the modification on the character of fracture and the portions of brittle and ductile fracture in particular areas of welded joints

The Jewish question during elections and 3rd and 4th terms in the Diet of the Galicia and Lodomeria (1870-1882)

Od 1861 r. datuje się historię Sejmu Krajowego w Galicji. Od pierwszej aż do ostatniej kadencji w sejmie zasiadali przedstawiciele społeczności galicyjskich Żydów. Wśród publikacji odnoszących się do kwestii żydowskiej w obradach Sejmu Krajowego, dominują opracowania odnoszące się do dwóch pierwszych kadencji sejmowych, dla których cezurę czasową stanowi uchwalenie konstytucji grudniowej, gwarantującej Żydom równouprawnienie.Celem niniejszej pracy jest zaprezentowanie kwestii żydowskiej podczas wyborów oraz posiedzeń Sejmu Krajowego III i IV kadencji w latach 1870-1882. Podstawowymi źródłami, które wykorzystano na potrzeby niniejszej pracy, była stenogramy sejmowe oraz materiały prasowe. Drugie ze wspomnianych źródeł posłużyło przede wszystkim do prześledzenia przebiegu kampanii wyborczej.The Diet of the Galicia and Lodomeria was formed in 1861. From first to last term representatives of the Galician Jewish communities were ellected. In the literature on the subject main focus of publications is set on two first terms (1st and 2nd), which refer to the period before the December constitution, which guaranteed legal equality to the Jews. The main aim of the thesis is to present the perception of questions regarding Jewish community during elections and 3rd and 4th terms for the Diet of the Galicia and Lodomeria. The basic sources were stenograms of diet’s sessions and daily press, which was used to reconstruct course of public discussion during the elections

The participation of galician Jews in the 1873 and 1879 parliamentary elections in the light of daily press in Galicia

W 1861 r. został utworzony w Wiedniu dwuizbowy parlament – Rada Państwa. Reprezentanci izby niższej wybierani byli w sposób pośredni przez sejmy krajowe. W 1873 r. przyjęto zmianę ordynacji wyborczej, na mocy której wprowadzono wybory bezpośrednie do izby poselskiej. W efekcie reprezentanci poszczególnych krajów monarchii austro-węgierskiej wybierani byli z pominięciem sejmów krajowych. W związku z uzyskaniem w 1867 r. równouprawnienia w wyborach brali także udział Żydzi galicyjscy. Wybory z lat 1873 i 1879 pokazały wewnętrzne podziały w środowisku żydowskich mieszkańców Galicji. Przebieg tych wydarzeń był żywo komentowany na łamach prasy galicyjskiej.In 1861 was established in Vienna Reichsrat, which was bicameral body. Parliamentary representatives of the lower house were elected by the diets of the crown lands. In 1873 the electoral system for parliament was changed to direct. From 1867 also galician Jews could participate in parliamentary elections. The elections in 1873 and 1879 demonstrated inner separation of galician Jews. Galician daily press related those events

Zastosowanie regresji z wykorzystaniem uczenia maszynowego i sieci neuronowych w badaniach właściwości tribologicznych warstw trudnościeralnych

Artificial intelligence is becoming commonplace in various research and industrial fields. In tribology, various statistical and predictive methods allow an analysis of numerical data in the form of tribological characteristics and surface structure geometry, to mention just two examples. With machine learning algorithms and neural network models, continuous values can be predicted (regression), and individual groups can be classified. In this article, we review the machine learning and neural networks application to the analysis of research results in a broad context. Additionally, a case study is presented for selected machine learning tools based on tribological tests of padding welds, from which the tribological characteristics (friction coefficient, linear wear) and wear indicators (maximum wear depth, wear area) were determined. The study results were used in exploratory data analysis to establish the correlation trends between selected parameters. They can also be the basis for regression analysis using machine learning algorithms and neural networks. The article presents a case study using these approaches in the tribological context and shows their ability to accurately and effectively predict selected tribological characteristics.Zastosowanie sztucznej inteligencji w różnych dziedzinach nauki i przemysłu jest coraz bardziej powszechne. Duża różnorodność metod statystycznych i predykcyjnych umożliwia użycie ich również w tribologii. Analiza danych liczbowych w postaci charakterystyk tribologicznych, struktury geometrycznej powierzchni oraz wielu innych wymaga zastosowania narzędzi informatycznych oraz statystycznych. Wykorzystanie algorytmów uczenia maszynowego i budowanie modelu sieci neuronowej umożliwi prognozowanie wartości ciągłych (regresja) oraz klasyfikowanie poszczególnych grup. W artykule autorzy dokonują przeglądu możliwości aplikacyjnych algorytmów uczenia maszynowego i sieci neuronowych do analizy wyników badań w szerokim kontekście. Dodatkowo zaprezentowano studium przypadku dla wybranych narzędzi uczenia maszynowego na podstawie przykładowych badań tribologicznych napoin, dla których przeprowadzono testy, w których wyznaczono charakterystyki tribologiczne (współczynnik tarcia, zużycie liniowe) oraz wskaźniki zużycia (maksymalna głębokość wytarcia, pole wytarcia). Wyniki badań były podstawą do przeprowadzenia analizy eksploracyjnej i posłużyły do wykazania korelacji pomiędzy wybranymi parametrami. Autorzy przekonują, że mogą one być podstawą do analizy regresji z wykorzystaniem algorytmów uczenia maszynowego i sieci neuronowych. W artykule zaprezentowano studium przypadku z wykorzystaniem tych podejść w kontekście tribologicznym oraz pokazano ich zdolność do dokładnego i skutecznego przewidywania wybranych charakterystyk tribologicznych

Fracture Energy and Fracture Morphology after Three-Point Bending Test of Welded Joints Made of Cast Steel Designed for Use in Power Sector, with and without the Addition of Rare Earth Metals

The paper reports the three-point bending test results of welded joints. The joints were made of chromium-molybdenum cast steel designed for the use at elevated temperatures. TIG (tungsten inert gas) welding technique was used. The fracture energy for particular joint zones and the stretch zone width (SZW) under the notch bottom were determined in a qualitative fracture toughness assessment. Fracture surface morphology was analyzed. The stretch zone measurement indicated a qualitative relationship between its width and the values of fracture energy. The results confirmed the influence of the modification on the character of fracture and the portions of brittle and ductile fracture in particular areas of welded joints

Wpływ dodatków tlenków metali ziem rzadkich na właściwości tribologiczne napoin stosowanych na elementach roboczych maszyn dla górnictwa

The article presents the results of research on pad welds made using consumables in the process of metal active gas welding (MAG) combined with plasma arc welding (PAW). The pad weld consisted of a buffer layer and a wear-resistant working layer. Cerium, yttrium and lanthanum oxides were added to the powders to modify the working (active) layer. The HV10 hardness and friction coefficient testing was followed by measuring wear tracks and determining wear indicators (maximum wear track depth and area). Yttrium oxide was found to have a remarkably beneficial effect on nickel-based pad welds. In the case of iron-based welds, the most favourable outcome was observed for lanthanum oxide.W artykule przedstawiono wyniki badań napoin wykonanych z wykorzystaniem materiałów spawalniczych metodą spawania łukowego elektrodą topliwą (MAG – metal active gas of welding) w połączeniu z napawaniem plazmowym (PAW – pasma arc welding). Napoina składała się z warstwy podkładowej (buforowej) oraz trudnościeralnej warstwy roboczej. Warstwę roboczą modyfikowano poprzez wprowadzanie do proszków tlenków ceru, itru i lantanu. Wykonane napoiny poddano pomiarom twardości HV10 oraz przeprowadzono testy tribologiczne, w których wyznaczono współczynnik tarcia. Następnie dokonano pomiarów śladów zużycia i zostały określone wskaźniki zużycia (maksymalna głębokość wytarcia, pole wytarcia). Wykazano korzystne oddziaływanie w szczególności tlenku itru dla napoin na osnowie niklu. W przypadku napoiny na osnowie żelaza najkorzystniejsze oddziaływanie odnotowano dla tlenku lantanu

The Influence of Remelting on the Properties of AlSi9Cu3 Alloy with Higher Iron Content

This article aims to evaluate the influence of remelting on the experimental Al-Si-Cu type alloy with higher iron content on mechanical properties in relation to the resulting structure. The remelting or recycling process is one of the means of reducing the production costs of the forge plant. The experimental part deals with the analysis of the results of mechanical properties, structural analysis, and the process of crystallization of structural components and their changes due to the increased iron content caused by remelting at different states of the examined alloy. The effect of remelting and ageing on microstructure was observed using a combination of different analytical techniques (light microscopy, scanning electron microscopy (SEM), and upon deep etching and energy dispersive X-ray analysis (EDX)). Tensile strength and elongation tests point to the negative effect of alloying, a gradual increase in wt% Fe and a change in the morphology of the iron phases, which began to manifest significantly after the fourth remelting. The process of natural ageing has been shown to be effective only on alloys with a lower number of remelting cycles, whereas the application of artificial ageing has resulted in improved mechanical properties in all the test alloys

Study of the Influence of Zirconium, Titanium and Strontium on the Properties and Microstructure of AlSi7Mg0.3Cu0.5 Alloy

The aim of the paper is to describe and specify the properties and microstructure of Al-Si alloy using Zr, a combination of Zr with elements used in the grafting of Al (Ti) alloys, and modification (Sr). Al-Si alloys with a combination of Zr and Ti and Sr elements represent an opportunity for the development of new aluminum alloys with a specific use. The experiment focused on the analysis of the synergistic effects of Zr with Ti and Zr with Sr on a AlSi7Mg0.3Cu0.5 alloy. The experimental alloys contained a constant Zr content of 0.15 wt. % and were alloyed with a gradual addition of Ti and Sr in the range of 0.1 to 0.3 wt. % for Ti, and 0.1 to 0.3 wt. % for Sr. The experimental samples were cast by meltable model casting technology. In variants with a constant addition of Zr 0.15 wt. % and a gradual addition of Ti, we observed an increase in the values of mechanical characteristics, with a significant decrease in ductility. When evaluating the structure of experimental alloys, Ti affected it by increasing the number of precipitated Zr phases. Experimental alloys with Zr and Sr addition were characterized by nucleation of Zr phases in angular morphology. It can be concluded that the investigated elements are expected to have a positive (strengthening) effect even at higher operating temperatures

Exploratory Data Analysis for the Evaluation of Tribological Properties of Wear-Resistant Surface Layers Modified with Rare-Earth Metals

The role of rare Earth metals in the improvement of the properties of metals and alloys has been analysed and described in multiple studies. Their effects on changes in microstructure and mechanical properties are most pronounced. This paper focuses on the beneficial effect of rare Earth metal oxides on the wear resistance of surface layers applied to castings intended for structural elements of machinery and equipment in mining and recycling. The experiment involved modifying prepared surfaces by adding CeO2, Y2O3, and La2O3. Hardness measurements, a scratch test, and tribological tests were performed under dry and fluid friction. The maximum wear track depth and track area were measured from the surface profile. To determine correlations between the results, exploratory data analysis was employed. Heatmaps were used to illustrate strong positive and negative interactions. The addition of oxides at increasing carbon content resulted in increased hardness, lower coefficient of friction, and reduced track area and maximum track depth. Strong negative interactions between the track area and maximum track depth were found. The differences resulting from the test conditions (fluid and dry friction) were discussed. This study demonstrated the suitability of exploratory data analysis for analysing research results and confirmed the improvement of modified surface wear resistance