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EN
Due to difficult pandemic situation with COVID-19 decease, as well as due to current geopolitical circumstances in the world, we are facing the shortage of steel and therefore the impossibility of delivering the contracted products within the agreed deadlines. It is thus necessary to find suitable steel for replacement. The procedure for selecting one such steel for substituting the deficit steel 25CrMo4,for the purposes of producing a responsible welded assembly, is described in this paper. After the careful analysis, the steel 42CrMo4 was taken into consideration as a possible substitute material. Prior to applying the new selected steel, it was necessary to perform the following tests: analyze its chemical composition, determine its most important mechanical properties and evaluate its weld ability. Then, the optimal welding and heat treatment technologies were determined, so that the quality of the responsible welded structure would meet all the requirements, as the structure made of originally used steel. For the new steel, all the mentioned and some additional tests were conducted and the appropriate welding technology was prescribed. To verify the selected technology, appropriate tests were conducted on the model welded samples, the results of which are presented in this paper. Based on the analysis of the obtained results, it was concluded that the 25CrMo4 steel can be replaced by the 42CrMo4 steel, however, with the mandatory application of appropriate supplementary measures.
EN
Purpose: In this study, the effect of heat treatment on the microstructure and mechanical properties of 42CrMo4 steel were investigated. Design/methodology/approach: The samples were annealed at 860°C for 120 min. followed by oil quenching and then tempered at temperatures between 480 and 570°C for 120 min. The microstructure of untreated 42CrMo4 steel mainly consists of pearlite and ferrite whereas the microstructure was found to be as a martensitic structure with a quenching process. Findings: The results showed that there is an increase in yield stress, ultimate tensile stress, hardness and impact energy, while elongation decreases at the end of the quenching process. Conversely, yield stress, ultimate tensile stress and hardness decrease slightly with the increasing of tempering temperature, while elongation and impact energy increase. Research limitations/implications: Other types of steels can be heat treated in a wider temperature range and the results can be compared. Practical implications: It is a highly effective method for improving the mechanical properties of heat treatment materials. Originality/value: A relationship between the mechanical properties and the microstructure of materials can be developed. The heat treatment is an effective method for this process.
EN
This paper presents the results of a numerical investigation into tube flanging by extrusion with a moving sleeve. Two cases of the extrusion process are investigated, each described with a different tool kinematics. Effects of flange diameter, gap height and tool motion on the extrusion process are examined. The numerical analysis is performed on 42CrMo4 steel tubes deformed at ambient temperature. Obtained numerical results are then used to determine metal flow patterns and examine force parameters in the extrusion process, as well as to determine a technological window for the investigated method.
PL
W artykule podano metodę porównywania struktur geometrycznych powierzchni SGP stali ze strukturą odniesienia żelaza armco na przykładzie procesu kulowania. Opracowanie wykonano na przykładzie porównania SGP stali 42CrMo4, z żelazem armco uzyskanych w takich samych warunkach obróbki.
EN
In this paper, a method was presented for comparing the surface texture of material obtained in the shot peening process with the reference texture of the Armco pure iron. The comparative investigation was carried out for the surface of the alloy steel 42CrMo4 and the Armco pure iron, while both materials had been treated the same way.
EN
The paper presents results of research tribological properties laser hardened steel 42CrMo4. Parameter influencing on the quality of the hardened surface was laser head speed. The study was conducted on friction tester pin-on-disc type T-11, and a counter sample disc was silicate. Parameter determining the quality of the surface layer is the intensity of wear. Based on the results we obtain information about the laser head speed to temper steel 42CrMo4 so as to maintain a high resistance to wear.
PL
W pracy przedstawiono wyniki badań właściwości tribologicznych stali 42CrMo4 poddanej hartowaniu laserowemu. Parametrem wpływającym na jakość hartowanej powierzchni była prędkości głowicy lasera. Badania tarciowe przeprowadzono na testerze typu trzpień-tarcza T-11, a przeciwpróbkę stanowiła tarcza silikatowa. Parametrem wyznaczającym jakość uzyskanej warstwy była intensywność zużycia. Na podstawie wyników badań uzyskujemy informację, z jaką prędkością głowicy możemy hartować stal 42CrMo4 tak aby zachować wysoką odporność na zużycie ścierne.
7
Content available Badania odporności erozyjnej wybranych materiałów
PL
W pracy analizowano wpływ właściwości mechanicznych Re, Rm i KC stali 51CrV4 i 42 CrMo4 stosowanych w młynach wirnikowych na odporność erozyjną k przy kątach padania strumienia ścierniwa 30°, 60° i 90°. Badania potwierdziły, że przy kącie padania padania ścierniwa 30° wzrasta odporność erozyjna wraz ze wzrostem granicy plastyczności Re i wytrzymałości na rozciąganie Rm. Przy kącie padania strumienia ścierniwa a = 90° wysoką odporność erozyjną uzyskują materiały posiadające wysoką udarność KC i wytrzymałość Rm.
EN
This paper presents an analysis of the influence of mechanical properties Re, Rm and KC of materials used in rotating mills on relative erosive resistance k for different angles of incidence of the abrasive stream. The conducted research has confirmed that, for small angles of incidence, the erosive resistance increases with an accompanying rise of yield point Re, tensile resistance Rm. At an incidence angle of the abrasive stream a = 90° materials possessing high impact resistance KC and strength Rm show high erosive resistance.
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