Pearlite

About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.

High-strength hot-dip galvanized steel sheet with excellent formability and impact resistance, and process for producing same

Abstract: Provided is a hot-dip galvanized steel sheet which has a tensile strength TS of 590 MPa or higher and excellent processability and which, even when no strain is introduced thereinto by pressing, highly absorbs energy in a low-strain range up to about 5% and has excellent collision resistance. Also provided is a process for producing the steel sheet. The galvanized steel sheet has a composition which contains, in terms of mass%, 0.04-0.13% C, 0.7-2.3% Si, 0.8-2.0% Mn, up to 0.1% P, up to 0.01% S, and 0.01-0.1% Al, with the remainder comprising iron and incidental impurities, and has a structure which comprises, in terms of areal proportion, at least 75% ferrite phase, at least 1% bainitic ferrite phase, and 1-10% pearlite phase, has a martensite phase content of up to 10% in terms of areal proportion, and satisfies (areal proportion of martensite)/((areal proportion of bainitic ferrite)+(areal proportion of pearlite))<=0.6, and in which the ratio of the Mn concentration in the ferrite phase to the Mn concentration in the second phase is 0.70 or above.

Precipitation behavior of M2N in a high-nitrogen austenitic stainless steel during isothermal aging

Abstract: The precipitation behavior of M 2 N and the microstructural evolution in a Cr-Mn austenitic stainless steel with a high nitrogen content of 0.43mass% during isothermal aging has been investigated using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The aging treatments have led to the decomposition of nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of M 2 N precipitate and austenitic matrix. This kind of precipitate morphology is similar to that of pearlite. However, owing to the non-eutectoidic mechanism of the reaction, the growth characteristic of the cellular precipitates is different from that of pearlite in Fe-C binary alloys. M 2 N precipitate in the cell possesses a hexagonal crystal structure with the parameters a = 0.4752nnm and c = 0.4429nm, and the orientation relationship between the M 2 N precipitates and austenite determined from the SADP is [0110] M2N //[101]γ, [2110] M2N //[010]γ,

In situ study of cementite deformation and its fracture mechanism in pearlitic steels

Abstract: The deformation and fracture behaviors of cementite in pearlitic steels during tensile tests were investigated by in situ scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and electron backscatter diffraction (EBSD). The results showed that the deformed structure had three different types of shear bands: shear deformation in the pearlite colonies, at the interfaces of the pearlite colonies and at the phase boundary between ferrite and cementite. The orientations of the shear bands were nearly anisotropic with respect to the tensile axis. The path of shear deformation developed at the dislocation walls and was propagated by the offset of the cementite along the dislocation walls. As the dislocations cut perpendicularly through the cementite layers, the single-crystalline cementite platelets were divided into many nanometer-sized subgrains by the effects of the shearing stress. This process hindered dislocation movement and led to the accumulation of complex dislocations at the adjacent ferrite lamellae. Thus, the plastic deformation of the cementite layers was characterized by bulging until they fractured. The pearlitic texture component was evenly distributed, and the crystallographic axes of the colonies were randomly oriented. Hence, three different shear models characterized the crack propagation process, which occurred in a linear fashion and could be considered the pearlite colonies as a displacement unit for forward expansion.