Effect of carbon concentration on tensile behaviour of pearlitic steels

Abstract

A quantitative relationship between ow stress and microstructure is studied for pearlitic steels incorporating 0 . 39 -0 . 77 wt-% carbon. The distribution of true lamellar spacing (S 0 ) is determined. It is found that S 0 depends on carbon concentration and pearlite transformation temperature accompanying a considerable distribution. The 0 . 2% proof stress is described as a function of the averaged S 0 but the in uence of the accuracy in S 0 measurement precludes satisfactory prediction of the 0 . 2% proof stress. High work hardening corresponds to the generation of phase stress caused by mis t plastic strain between ferrite and cementite. The stress partitioning behaviour between ferrite and cementite is veri ed by in situ neutron diffraction during tensile deformation. MST/5782Professor Tomota, Mr Watanabe and Mr Kanie are in the

Strengthening of Pearlitic Steel by Ferrite/Cementite Elastic Misfit Strain

“…As a result, they demonstrated that the macroscopic yield strength of pearlitic steel corresponds to the onset of plastic flow in the ferrite matrix; furthermore, the stress necessary for this clearly increases with decreasing interlamellar spacing. 8) This enables us to understand that the yielding of pearlitic steel stems from that of the ferrite matrix, although the Orowan mechanism has not been proven to be appropriate for explaining ferrite strengthening in pearlitic steel.…”

Modeling of the Barkhausen jump in low carbon steel

“…21 Additionally, the distance between the cementite lamellae decreases with decreasing carbon content. 22 It is known that the domain walls tend to lie parallel to the cementite lamellae in the pearlite grains. Then, the coercive field produced by these defects increases with the carbon content, due to the change in the DWS 17 area.…”

Estudo Da Microestrutura De Um Aço Eutetóide Laminado a Quente Utilizando Microscopia De Força Atômica

“…Os valores mais baixos observados por Lima [9] se referem ao fato do aço que ela estudou ter sofrido deformação plástica. Vários autores têm pesquisado como a deformação plástica altera a microestrutura de aços eutetóides orientando as colônias na direção de deformação e reduzindo o espaçamento interlamelar da perlita [1,[7][8].…”

“…A diminuição do espaçamento interlamelar pode ser obtido por meio de tratamentos térmicos controlados de maneira tal que a transformação austenita-perlita ocorra entre 550 e 600 ºC, como é feito na fabricação de trilhos ferroviários modernos [2,7]. Além de tratamentos térmicos, a conformação mecânica a frio, por trefilação, permite obter espaçamentos interlamelares ainda menores, o que resulta em aços com resistência a tração da ordem de 4000 MPa após 97% de redução total da área da seção transversal [1,8,9].…”