|
| |
|
|
The Influence of Structure and Heat Treatment on Properties of Steels for Bearings
Pytlíčková, Kateřina ; Dočkal, Ing, Michael (referee) ; Věchet, Stanislav (advisor)
Heat treatment influences structure and characteristics of treatmented material. Good heat treatment of steels for bearings ensures hardness of matrix 60 - 65 HRC, whereas structure has be formed by tempered fine needle-shaped martensite with definite part of residual austenite. Carbides should be evenly dispersed, they mustn´t create carbide network and carbide lines. Quality of steels for bearings is also influenced by volume and morphology of inclusions in the matrix. In this diploma thesis various conditions of heat treatment were to be set up with the aim of choose the optimal ones. These ensures perfect martensite transformation and full hardening of all component. Quenching from 760 °C – 770 °C was quite unsatisfactory. At this temperature resulting structure was ferritic-perlitic, because martensite transformation did not pass. Too long hold on hardening temperature also had unfavourable influence on resulting structure and characteristics. In this case, structure was created by very coarse needle-shaped martensite. Coarsening of martensite needle locally exceeded maximum allowed level. In the structure there was also possible to watch partly soluted globular carbides. Optimal heat treatment is quenching from 850 °C – 870 °C followed by tempering at 220 °C. Resulting structure quite agree with above-mentioned needs. This heat treatment can be recommended for technical practise.
|
|
|
Welding of stainless steel in sewage treatment plant
Zána, Jiří ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
This bachelor thesis is dealing with stainless steel welding, especially for waste water treatment plants use. The thesis presents two most suitable stainless steel materials that eliminate fundamental disadvantages of other steel types. In the experiment three types of welding are tested for both materials and each weld is performed using two amperages. The weld bead and root WPS surface is evaluated for particular samples. For others the weld macrostructure is assessed.
|
|
| |
|
|
Methods to increase the visibility of the original austenite grain boundaries in steels
Gamanov, Štěpán ; Klakurková, Lenka (referee) ; Juliš, Martin (advisor)
This thesis deals with methods of revealing prior austenite grains in steels. The objective was to describe and demonstrate these basic methods on samples. The theoretical part deals with the importance of austenite grain and its size, with description of base methods of revealing austenite grains, and with methods of determination of grain size. The practical part consists of pictures and commentary of samples wich were made with some of the base methods described in the theoretical part. Conclusion consists of comparison of our and external results and also expanding commentary on individual methods.
|
|
|
Metody tavného svařování pro výrobu ocelových nádrží na užitkovou vodu
Nevěděl, Jan
The folowing pages of bachelor thesis are talking about utilisation of fusion welding in water tank manufacture process. Due to the most frequent use of MIG, MAG and TIG welding types, this thesis will be largely focused on the above mentioned methods. Because of dynamical development of welding technologies thesis will look at economical side of fusion welding. Also will be talking about other fusion connecting types. In the other part of the thesis we will look at basic principles of welding and then its application in at technological processes, focused on behaviour at water tanks. The last part of the thesis will be centralized on rust protection and flaw detectection in welds. Whole labor is supported with photographs from water tank manufacture process.
|
|
| |
|
|
Methods to increase the visibility of the original austenite grain boundaries in steels
Gamanov, Štěpán ; Klakurková, Lenka (referee) ; Juliš, Martin (advisor)
This thesis deals with methods of revealing prior austenite grains in steels. The objective was to describe and demonstrate these basic methods on samples. The theoretical part deals with the importance of austenite grain and its size, with description of base methods of revealing austenite grains, and with methods of determination of grain size. The practical part consists of pictures and commentary of samples wich were made with some of the base methods described in the theoretical part. Conclusion consists of comparison of our and external results and also expanding commentary on individual methods.
|
|
| |
|
|
Welding of stainless steel in sewage treatment plant
Zána, Jiří ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
This bachelor thesis is dealing with stainless steel welding, especially for waste water treatment plants use. The thesis presents two most suitable stainless steel materials that eliminate fundamental disadvantages of other steel types. In the experiment three types of welding are tested for both materials and each weld is performed using two amperages. The weld bead and root WPS surface is evaluated for particular samples. For others the weld macrostructure is assessed.
|
guest ::
