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Application of small punch test for determination of high temperature materials characteristics
Ječmínka, Marek ; Dobeš, Ferdinand (referee) ; Dymáček, Petr (advisor)
Diploma thesis is focused on mechanical properties testing by small punch test and comparison of these properties with mechanical properties obtained by conventional tensile test. Steels P92 and AISI 316L in a shape of discs were tested. There were determined values of mechanical properties, namely yield stress, and ultimate tensile stress, obtained by the small punch test – constant deflection rate in this thesis. Values of initial stress and residual stress were evaluated from relaxation small punch test. Mechanical properties obtained by small punch test – constant deflection rate, and small punch test – relaxation, respectively, are compared with mechanical properties obtained by conventional tensile test, and relaxation tensile test, respectively. There were proposed own empirical relationships for restatement of mechanical properties obtained by small punch test to mechanical properties obtained by conventional tensile test in the thesis. Relatively small agreement of results obtained by small punch test, and conventional tensile test was demonstrated by a comparison. Application of own empirical relationships resulted in better agreement. Very good agreement of results of small punch test – relaxation, and relaxation tensile test was shown by their comparison.
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Application of small punch test for determination of high temperature materials characteristics
Ječmínka, Marek ; Dobeš, Ferdinand (referee) ; Dymáček, Petr (advisor)
Diploma thesis is focused on mechanical properties testing by small punch test and comparison of these properties with mechanical properties obtained by conventional tensile test. Steels P92 and AISI 316L in a shape of discs were tested. There were determined values of mechanical properties, namely yield stress, and ultimate tensile stress, obtained by the small punch test – constant deflection rate in this thesis. Values of initial stress and residual stress were evaluated from relaxation small punch test. Mechanical properties obtained by small punch test – constant deflection rate, and small punch test – relaxation, respectively, are compared with mechanical properties obtained by conventional tensile test, and relaxation tensile test, respectively. There were proposed own empirical relationships for restatement of mechanical properties obtained by small punch test to mechanical properties obtained by conventional tensile test in the thesis. Relatively small agreement of results obtained by small punch test, and conventional tensile test was demonstrated by a comparison. Application of own empirical relationships resulted in better agreement. Very good agreement of results of small punch test – relaxation, and relaxation tensile test was shown by their comparison.
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Applicability of small punch test to determine the material mechanical properties at room and high temperatures
Dymáček, Petr ; Ječmínka, M.
The paper is focused on testing of mechanical properties by small punch test (SPT) and comparison of these properties with mechanical properties obtained by conventional tensile tests of steels P92 and AISI 316L. The yield stress and ultimate tensile stress obtained by SPT at constant deflection rate (SPT-CDR) were evaluated. Values of initial stress and residual stress were evaluated from relaxation small punch test (SPT-R). Mechanical properties obtained by SPT-CDR and SPT-R are compared with mechanical properties obtained by conventional tensile test and relaxation tensile test, respectively. Modified empirical relationships for an assessment of tensile test properties from quantities determined by small punch test are proposed. Good agreement of results of SPT-R and relaxation tensile test is shown by their comparison.
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Prediction of static materials properties of P92 steel based on small punch test
Dymáček, Petr ; Ječmínka, M. ; Abendroth, M.
Small punch testing under constant deflection rate of P92 steel at room temperature was performed. The experimental SPT curves were used for prediction of yield and ultimate strength based on empirical formulas published in the literature and also by numerical inverse analysis with help of finite element method. Conventional tensile tests were performed for verification of the data derived from small punch testing. Good agreement was found in the case of ultimate strength. Determination of the yield strength is less accurate mainly due to significantly lower values of force at yield compared to maximum force measured by SPT. Two approaches for evaluation and determination of the force at yield limit in SPT diagram and estimation of the yield strength of the material are described in the article.
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