Development of microstructure and texture of medium carbon steel during heavy warm deformation

Abstract

The microstructure and texture development of a medium-carbon steel (0.36% C) during heavy warm deformation (HWD) was studied using scanning electron microscopy and electron back scattering diffraction. The spheroidization of pearlite is accelerated due to the HWD, which leads to the formation of completely spheroidized cementite already after the deformation and coiling at 873 K (600°C). The homogeneity of the cementite distribution depends on the cooling rate and the coiling temperature. The cooling rate of about 10 K/s (ferrite-pearlite prior to HWD) and deformation/coiling at 943-973 K (670-700°C) lead to a homogeneous cementite distribution with a cementite particle size of less than 1 lm. The ferrite softening can be attributed to continuous recrystallization. Even up to fairly high deformation/coiling temperatures of 983 K (710°C) the texture consists of typical deformation components. During the continuous recrystallization the amount of high angle grain boundaries can increase up to 70% with a ferrite grain size of 1-3 lm. An increase of the cooling rate up to 20 K/s (ferrite-pearlite-bainite prior to HWD) deteriorates the homogeneity of the cementite distribution and the softening of ferrite in the final microstructure.

Cylindrical Cup Manufacturing Using 12 mm Thick Circular Blanks of AISI 1040 Graded Medium Carbon Steel: an Innovative Approach

“…5(a)-5(b)) with local lamella divisions, in the vicinity of ferrite sub boundaries are also observed. According to Storojeva et al, 20) the interface adjacent to the sub boundary in the cementite lamella with a large local curvature and the surrounding ferrite provokes a quick carbon dissolution that leads to a local lamella division. Further, very few numbers of undesirable fine spheroidized cementite particles (about 0.1-0.2 μm) (circle mark in Figs.…”

“…These cementite particles are formed from fragments of the former lamellae located at a prior austenite grain boundary, wherein an accelerated diffusion along the boundary, leads to a faster coarsening of these cementite fragments. 20) Few partially spheroidized cementites (double arrow mark in Figs. 5(a)-5(b)) with local lamella divisions, in the vicinity of ferrite sub boundaries are also observed.…”

The Effect of Rolling Temperature on the Microstructure and Mechanical Properties of Surface-Densified Powder Metallurgy Fe-Based Gears Prepared by the Surface Rolling Process

“…When the warm rolling process is conducted, the parts are deformed under a certain temperature range, which is usually higher than the recovery temperature but lower than the recrystallization starting temperature [6]. During the process of warm deformation, work hardening will take place in the samples, accompanied by dynamic recovery softening and static softening within the gap moment of the deformation, although the work hardening effect is dominant [7]. The hardness and yield strength of the metals are dependent on the degree of work hardening and softening [8].…”

Ductile Fracture Characterization for Medium Carbon Steel Using Continuum Damage Mechanics

“…Recently, medium carbon steel heat-treated to obtain spheroidized cementite in its microstructure is being used as raw material for sheet forming processes, due to its better formability properties [17]. Due to large plastic strains imposed to this kind of manufactured parts, cracks and other defects observed are mostly related to ductile damage evolution.…”