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Fatigue Properties of Stainless Austenitic Steel
Sedlák, Martin ; Němec, Karel (referee) ; Věchet, Stanislav (advisor)
Final bachelor thesis „Fatigue characteristics of anti-corrosion austenitic steels" is aimed at problematic of mechanics and fatigue properties of Chrome-Nickel austenitic steel CSN EN X2CrNiMo 18-14-3. Thesis aim is to pass judgment on influence of stress cycle asymmetry on fatigue characteristics on high cyclic loading on above mentioned steel. Design Haigh and Smith diagrams. Component of the thesis is metallographical and chemical analysis, mathematical values processing obtained from fatigue tests and also determine primary mechanical properties. Further Wohler´s curves are stated at different stress cycle asymmetry. According to mathematical values processing is designed Haigh and Smith diagrams and fatigue index is calculated. From obtained data result that medium stress of cyclic stress, has of principle influence on appreciate fatigue limit of engaged material.
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Compared HAZ the methods of welding TIG, MAG and CMT
Šoulák, Petr ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The bachelor thesis was to compare the HAZ size for the TIG, MAG and CMT methods. The welded materials were low carbon steel and austenitic stainless steel. Samples of 250x50 mm size and 2 mm thick were welded with butt weld without a gap. In the first part of experiment, samples were welded at the same welding speed. The second part concerned only CMT, where the optimal welding speed was used. For selected samples, the HAZ size was measured and compared in macroscopic images.
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Microstructural stability of austenitic steels during fatigue loading
Kudelka, Martin ; Válka, Libor (referee) ; Pantělejev, Libor (advisor)
This diploma thesis studies the structure of selected austenitic stainless steels which were fatigued at room and depressed temperatures. The theoretical part is divided into three parts. The first one defines the austenitic stainless steels with accent to their chemical composition and microstructure. Second part is dedicated to deformation-induced martensite formation. The third part shows the mechanisms and stages of damage due to cyclic straining. The experimental part is focused especially on the observing of microstructural changes by methods of colour metallography and their relation to stress-strain response of material under selected conditions of fatigue loading. Series of samples of 304 and 316L steels were prepared by colour etching and their microstructures were documented using optical microscopy. Then the semi-quantitative measurements of presence and morphology of deformation-induced martensite were done and the results were discussed and correlated with fatigue damage level.
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Recovery and recrystallization of austenitic steel 08Cr18Ni10T
Čech, Jan ; Gregor, Martin (referee) ; Foret, Rudolf (advisor)
This thesis deals with influences of graded deformations, temperatures and holding times on the grains and subgrains size in steel 08Cr18Ni10T. In literary part of the thesis there are described static and dynamic annealing treatments, then also austenitic stainless steels and some selected types of their processing. In experimental part there is studied grain size on differently deformed samples annealed in temperature range 1050–1200 °C for 10, 50 and 100 minutes. Analysis of present structures units was perform by EBSD. Except of that, there were realized chemical analysis of selected inclusions and also hardness test were realised. Achieved measurement shown, that grain size of chosen steel is depended on all 3 variable values.
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Stick welding carbon and high-alloy steels
Hendrych, Marek ; Vaněk, Mojmír (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with analysis of manual metal arc welding method or method 111. In the research part of this thesis are discused principles of this method, welding power sources and additional welding material-coated elecrodes. Further the thesis is focused on the weldability of steels, especially carbon steels and austenitic stainless steels. In the experimental part was accomplished measurement of operational characteristics of coated electrods. Measurement was carried out on sample of cabon steel S235JR according to ČSN EN and austenitic stainless steel X5CrNi18-10 accordig to ČSN EN. The evaluation envolves a comparison of the results and their justifications.
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On the analysis of thin-wall parts sawing
Spáčil, Radek ; Dvořáková, Jana (referee) ; Píška, Miroslav (advisor)
Master‘s thesis deals with sawing of the thin-walled parts with high speed steel slitting saw. At first the most used conventional and unconventional possibilities of materiál cutting are described by a form of search. The next chapter describes forces arising from splitting saw machining, including their dependence on a specific cutting force, a chip cross section and a engagement angle. The second part of the thesis deals with the technological improvement of the cutting process, where three possible solutions are considered – geometry of the cutting tool, PVD coating deposition of the cutting tool and process fluid change. In the experimental part non coated slitting saw with burrs, non coated deburred slitting saw and coated slitting saws are compared. Used coatings were Ti(C,N), Cr-Al-Si-N, Al-Cr-B-N, and TripleCoating Cr, which is consisting of three layers TiN + (Al,Ti)N + Cr-Al-Si-N. The experiment has shown that the cutting forces inceases as the edge radius and wear level of the cutting tool increases. Coated cuttung tools has shown lower differences between the first and the last cut. Slitting saws have been also used in real cutting process to verify experimental results.
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Influence of chemical composition, casting temperature and the used deoxidation on technological properties of austenitic chrome-nickel steels
Myška, Martin ; Dulava, Martin (referee) ; Záděra, Antonín (advisor)
The thesis deals with austenitic stainless steel ČSN 42 2930, ASTM A351 CF8 and evaluates its mechanical and technological properties. The first part of this work is focused on properties of austenitic steels, it describes the process of melting and casting of steel on the basis of the realized experiments. It also deals with the mechanical properties of the used steel. The second section of the thesis is dedicated to the historical development of the maximum fluidity tests and main factors affecting the maximum fluidity of alloys. Maximum fluidity values have been processed on the basis of different casting temperatures of the maximum fluidity tests of the used steel. The third part of the work examines the effect of the casting temperature on the feeding distance of the used steel as well as the influence on its shrinkage rate.
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Stick welding carbon and high-alloy steels
Hendrych, Marek ; Vaněk, Mojmír (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with analysis of manual metal arc welding method or method 111. In the research part of this thesis are discused principles of this method, welding power sources and additional welding material-coated elecrodes. Further the thesis is focused on the weldability of steels, especially carbon steels and austenitic stainless steels. In the experimental part was accomplished measurement of operational characteristics of coated electrods. Measurement was carried out on sample of cabon steel S235JR according to ČSN EN and austenitic stainless steel X5CrNi18-10 accordig to ČSN EN. The evaluation envolves a comparison of the results and their justifications.
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Recovery and recrystallization of austenitic steel 08Cr18Ni10T
Čech, Jan ; Gregor, Martin (referee) ; Foret, Rudolf (advisor)
This thesis deals with influences of graded deformations, temperatures and holding times on the grains and subgrains size in steel 08Cr18Ni10T. In literary part of the thesis there are described static and dynamic annealing treatments, then also austenitic stainless steels and some selected types of their processing. In experimental part there is studied grain size on differently deformed samples annealed in temperature range 1050–1200 °C for 10, 50 and 100 minutes. Analysis of present structures units was perform by EBSD. Except of that, there were realized chemical analysis of selected inclusions and also hardness test were realised. Achieved measurement shown, that grain size of chosen steel is depended on all 3 variable values.
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On the analysis of thin-wall parts sawing
Spáčil, Radek ; Dvořáková, Jana (referee) ; Píška, Miroslav (advisor)
Master‘s thesis deals with sawing of the thin-walled parts with high speed steel slitting saw. At first the most used conventional and unconventional possibilities of materiál cutting are described by a form of search. The next chapter describes forces arising from splitting saw machining, including their dependence on a specific cutting force, a chip cross section and a engagement angle. The second part of the thesis deals with the technological improvement of the cutting process, where three possible solutions are considered – geometry of the cutting tool, PVD coating deposition of the cutting tool and process fluid change. In the experimental part non coated slitting saw with burrs, non coated deburred slitting saw and coated slitting saws are compared. Used coatings were Ti(C,N), Cr-Al-Si-N, Al-Cr-B-N, and TripleCoating Cr, which is consisting of three layers TiN + (Al,Ti)N + Cr-Al-Si-N. The experiment has shown that the cutting forces inceases as the edge radius and wear level of the cutting tool increases. Coated cuttung tools has shown lower differences between the first and the last cut. Slitting saws have been also used in real cutting process to verify experimental results.
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