The austenite: Pearlite reaction

The Cementite Spheroidization Process in High-Carbon Steels with Different Chromium Contents

“…Although the existence of the DET reaction has been known for years, only a limited number of studies of the mechanism and especially of the effect of alloying elements on the DET reaction are available. The work has mainly been performed on SAE 52100 bearing steel, [3][4][5][6][7][8][9][10][11][12] for which the achievement of a well-spheroidized structure is necessary before the subsequent machining and further bainitic or martensitic heat treatment. [15,16] This work has shown that a change in Cr content in hypereutectoid steels has a significant influence on the cementite spheroidization process.…”

“…Annealing above the A 1 temperature but below the A cm temperature accomplishes an incomplete dissolution of cementite, then austenite with fine cementite particles normally transforms into a mixture of ferrite and cementite by either the pearlitic reaction [10] or by the divorced eutectoid transformation reaction (DET) [5,8,9,11] upon slow cooling. The latter leads to a soft microstructure of spherical cementite particles in a ferritic matrix.…”

Modeling Pearlite Transformation in Super-high Strength Wire Rods: I. Modeling and Simulation in Fe–C–X Ternary Alloys

“…Another notable feature of pearlite nucleation is that nucleation rate increases with time, of which two possibilities were discussed. One was based upon the idea of incubation period, 4) and the other was ascribed to the increase of the surface area of the 1st nucleating phase (ferrite or cementite) on which the other phase (cementite or ferrite) nucleates. 9) Mehl and Hagel 4) reported nucleation rates averaged over a certain time range in a wide temperature range (560-700°C).…”

“…At early times Johnson-MehlAvrami (JMA) equation was employed to calculate the isothermal transformation curve of pearlite. 4) Before we apply the JMA type analysis, a couple of points are noted. In the first, the theory can take into account the effects of hard impingement by extended volume and phantom nuclei.…”

Microstructure and Mechanical Property of Copper Bearing Eutectoid Steel

“…(1) Where x, t and D are the diffusion distance, the time and the diffusion coefficient, respectively. The activation energy for interfacial diffusion is generally believed to be a half of that for lattice diffusion, 12) so that the interfacial diffusion coefficient of Cu, D Cu Gb , is calculated with Eq. (2) using an activation energy for the lattice diffusion of Cu in austenite, 280 000 J/mol.…”