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The evaluation of the lifetime period of welded frame for hydraulic press machine RONDOPRESS
Čermák, Petr ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
Petr Čermák: Service time assessment of the welded frame for the hydraulics of RONDOPRESS press machine The goal of this thesis is to assess durability of the welded frame for the hydraulics of RONDOPRESS press machine, which is used at the bakery sector in the food industry. The press machine chamber is made of stainless steel, because of food (dough) processing. But the strengthened part of the press machine consists of a carbon steel frame with a hydraulic cylinder. For the life of the RONDOPRESS machine is determining the rigidity and durability of the frame. Therefore it is necessary to carry out a study of carbon steel weldability, choose a suitable welding method and then make an evaluation of welded frame construction used in terms of weld joints in analyzed areas. Practical part consists of the frame computer model design, stress calculations and the service time calculation for required 1,825,000 cycles, choosing the appropriate welding method and avoiding undesired deformations. The final output is an operational frame of the RONDOPRESS press machine that meets the required service time specified by the number of production process cycles.
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Optimalization of the welding process for low - pressure tubular sets
Urbánek, Štěpán ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The diploma thesis examines the implementation of the production process of low-pressure pipe sets for hydraulic aggregates in the company Bosch Rexroth. The first part presents a literature analysis of used technologies and basic welded materials. The second part focuses on selected subprocesses ensuring the production and proposals for their streamlining. It includes a summary of responsibilities across departments and a template for processing the necessary technical documentation for the smooth running of production. Another proposal includes a technological procedure for practical verification of the production, which simultaneously serves as a basis for measuring the welding time. The reason for the implementation of this production was the extended delivery time of pipe sets from suppliers and possible financial savings. The practical part is concluded with a technical and economical evaluation, which expresses the possible financial savings in the production of low-pressure pipelines instead of the current state involving the cooperation with suppliers.
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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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Durability testing of replaceable inserts in cylindrical turning of carbon steel
Smolík, Martin ; Vítek, Jiří (referee) ; Sedlák, Josef (advisor)
The thesis deals with the problems in the field of durability testing of replaceable inserts for longitudinal steel turning. The main objective of the thesis is the analysis of the cutting process based on the results of the performed cutting tests. The cutting tests will be carried out comparatively by testing pairs of inserts, compared to each other. Wear observation is carried out by optical method using a workshop microscope and special software designed to process the acquired images. The output of the work will be an illustration of the different behaviour of the standard and the upgraded set of cutting inserts under different configurations of cutting conditions. The work provides a comprehensive view of the cutting tool testing process and quantifies the degree of influence of the various factors entering into the cutting edge wear process.
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Optimalization of the welding process for low - pressure tubular sets
Urbánek, Štěpán ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The diploma thesis examines the implementation of the production process of low-pressure pipe sets for hydraulic aggregates in the company Bosch Rexroth. The first part presents a literature analysis of used technologies and basic welded materials. The second part focuses on selected subprocesses ensuring the production and proposals for their streamlining. It includes a summary of responsibilities across departments and a template for processing the necessary technical documentation for the smooth running of production. Another proposal includes a technological procedure for practical verification of the production, which simultaneously serves as a basis for measuring the welding time. The reason for the implementation of this production was the extended delivery time of pipe sets from suppliers and possible financial savings. The practical part is concluded with a technical and economical evaluation, which expresses the possible financial savings in the production of low-pressure pipelines instead of the current state involving the cooperation with suppliers.
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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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The evaluation of the lifetime period of welded frame for hydraulic press machine RONDOPRESS
Čermák, Petr ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
Petr Čermák: Service time assessment of the welded frame for the hydraulics of RONDOPRESS press machine The goal of this thesis is to assess durability of the welded frame for the hydraulics of RONDOPRESS press machine, which is used at the bakery sector in the food industry. The press machine chamber is made of stainless steel, because of food (dough) processing. But the strengthened part of the press machine consists of a carbon steel frame with a hydraulic cylinder. For the life of the RONDOPRESS machine is determining the rigidity and durability of the frame. Therefore it is necessary to carry out a study of carbon steel weldability, choose a suitable welding method and then make an evaluation of welded frame construction used in terms of weld joints in analyzed areas. Practical part consists of the frame computer model design, stress calculations and the service time calculation for required 1,825,000 cycles, choosing the appropriate welding method and avoiding undesired deformations. The final output is an operational frame of the RONDOPRESS press machine that meets the required service time specified by the number of production process cycles.
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Changes in dislocation substructure of S235JR steel during fatigue loading
Jandová, D. ; Gajdoš, Lubomír ; Šperl, Martin ; Kaiser, J.
Changes in dislocation substructure were studied in normalized and annealed S235JR steel in relation to the number of symmetrical reversed stress cycles with the amplitude σa = 242 MPa and corresponding mean life Nf = 17,950 cycles. The microstructure of the steel consisted of ferrite with a small amount of pearlite. The substructure was observed in as received condition and after application of various relative numbers of cycles n/Nf, these being 0.25, 0.50 and 0.75. An irregular dislocation net occurred in the virgin specimen, however, during cyclic loading the dislocations started to accumulate gradually in slip bands and to form a cell substructure in grains of favourable crystallographic orientations. Total dislocation density, dislocation density in slip bands and inter-band distance were measured using transmission electron microscopy (TEM). The total dislocation density was found to slightly decrease and the density in slip bands to increase with increasing number of cycles. The results concerning the dislocation density were compared with changes in the microplastic limit (MPL) which were determined by the measurement of the inductance of the “specimen - coil” system. They consisted in a rapid initial decrease at the first stage of the fatigue process and in a gradual increase during the major part of the life. These changes can be interpreted on the basis of changes in dislocation density as was verified independently by X-ray diffraction and nanoindentation tests. On the basis of the measurement of dislocation density by TEM it appears that changes in MPL can be connected with the dislocation density in slip bands rather than with the total dislocation density.
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