Hot tensile and creep data were obtained for 2.25Cr-1Mo steel, ASTM A387 Gr.22CL2, at the temperatures of 500-550-600-650-700 °C. Using the concept of equivalence between hot tensile data and creep data, the results were analyzed according to the methodology based on Kachanov Continuum Damage Mechanics proposed by Penny, which suggests the possibility of using short time creep data obtained in laboratory for extrapolation to long operating times corresponding to tens of thousands hours. The hot tensile data (converted to creep) define in a better way the region where β=0 and the creep data define the region where β=1, according to the methodology. Extrapolation to 10,000 h and 100,000 h is performed and the results compared with results obtained by other extrapolation procedures such as the Larson-Miller and Manson-Haferd methodologies. Extrapolation from ASTM and NIMS Datasheets for 10,000 h and 100,000 h as well as data from other authors on 2.25Cr-1Mo steel are used for assessing the reliability of the results.

Ensaios de tração a quente e fluência foram realizados na liga Kanthal A1 na faixa de temperatura de 600º a 800ºC. Cada um desses conjuntos de dados foram analisados separadamente de acordo com suas próprias metodologias, mas, neste trabalho, uma tentativa foi realizada para se estabelecer uma correlação entre os mesmos. Um novo critério proposto para converter dados de tração para fluência torna possível a análise conjunta desses dois grupos de resultados de acordo com relações usuais de fluência como: Norton, Monkman-Grant, Larson-Miller e outros. A notável compatibilidade entre os dois conjuntos por esse procedimento sugere que dados de tração a quente podem ser convertidos para dados de fluência para a liga Kanthal A1, como verificado anteriormente para outros materiais metálicos.

Hot tensile and creep tests were carried out on Kanthal A1 alloy in the temperature range from 600 to 800ºC. Each of these sets of data were analyzed separately according to their own methodologies, but an attempt was made to find a correlation between them. A new criterion proposed for converting hot tensile data to creep data, makes possible the analysis of the two kinds of results according to usual creep relations like: Norton, Monkman-Grant, Larson-Miller and others. The remarkable compatibility verified between both sets of data by this procedure strongly suggests that hot tensile data can be converted to creep data and vice-versa for Kanthal A1 alloy, as verified previously for other metallic materials.

Creep results on 2.25Cr-1Mo were obtained at 600 °C, 650 °C and 700 °C at five stress levels, under constant load, in air and vacuum. Two chambers were specially developed for carrying out creep testing in controlled environment, with the possibility of accommodating inside them the load train, the extensometry system and the thermocouples. The creep machines used in this project present the advantage of allowing the performance of both constant load or constant stress creep testing, using interchangeable profiles. The preliminary set of constant load data reported here was analyzed according to the conventional methodology of creep data analysis, with the identification of parameters of the Norton, Arrhenius, Monkman-Grant and some extrapolation relations involving stress, temperature, minimum creep rate and rupture time. The results indicate a strong effect of the oxidation phenomenon on the creep behavior of this steel. The data were consistent and meaningful so that the developed chambers can be considered to present good performance in the generation of creep data in vacuum.