Application of hardenability concepts in heat treatment of steel

Hardenability of Steel

“…For this reason, Jatczak's data was limited to those steels that were quenched from 925 C (1700 F) (28,30). Doane also showed in his review that the effect of manganese of up to 1% is greater for either low-or high-carbon steels than medium-carbon steels (28).…”

“…In this work, hardenability was shown to be a function of grain size and steel composition and was calculated in terms of the 'ideal critical diameter' (D I ), which, as discussed previously, was defined as the largest bar diameter that can be quenched to produce 50% martensite at the center after quenching in an 'ideal' quench, that is, under infinite quenching severity. This is a microstructural definition, and there is no reference to hardness (28). The use of hardness measurements to determine the position where 50% martensite occurs does not Table 3 Effects of alloying elements on steel properties a Element b,c,d Effect on Steel Properties b Boron (B) Small amounts substantially increase hardenability.…”

“…One potential problem is that a multiplying factor assigned to an element is not always directly proportional to the total amount of that element. Another potential limitation to the multiplicative approach is that there is the potential for interaction effects, so that when two or more elements are present together, their net effect may be different than if only one of the elements is present alone (28,29).…”

A Pure Implicit Finite Difference-Based Modeling Approach for Prediction of the Hardenability of Eutectoid Steel

“…In order to obtain D I data from experimentally determined D C data, Grossmann developed a D I -D C master plot based on analytical heat transfer calculations considering constant thermophysical data [8]. Grossmann's approach to the evaluation of hardenability is quite reasonable, and his work has been followed by a series of publications attempting to extend the application range or to increase its accuracy [9,10]. However, in these studies, the definition and measurements of hardenability have been limited to hardness, and the details of the solid-state transformations in steel are completely ignored.…”

Determinação de velocidades críticas de têmpera em aços por meio de curvas de resfriamento

“…O software analisador de imagens apresenta os resultados obtidos pela análise computacional em tabelas e histogramas de freqüência das áreas dos grãos, o que corresponde ao número de grãos obtidos pela análise do campo da amostra divididos em intervalos de área estabelecidos pelo operador, conforme indicado nos itens 12.3.4 e 13.9.7 [54], Em seguida, são calculados a área dos grãos, Ai, para os N grãos medidos e a área de grão média, Ã, em unidades de área T: Tamanho Médio do Grão. (22) O primeiro intervalo de áreas definido pelo software analisador de imagens, geralmente não apresenta boa distribuição, sendo portanto subdividido em outros 6 ou 12 intervalos, que apresentamse diferenciados nas tabelas e histogramas apresentados em amarelo para facilitar a interpretação e visualização dos resultados.…”