Microstructural modification of plain carbon steels irradiated by high-energy electron beam

Abstract

The main objective of the present study is to analyze the microstructural modification of the surface hardened by the irradiation of high-energy electron beam in 0.18 pct C and 0.38 pct C plain carbon steels. Steel samples were irradiated using an electron accelerator (1.4 MeV), and the detailed microstructures of the irradiated surface were examined. Upon irradiation, the ferrite-pearlite structure near the sample surface was changed to the dual-phase structure, i.e., ferrite and martensite, and fine particles or needlelike lamellae were observed in the ferrite/martensite interface. In order to investigate these complex microstructures as well as the martensitic transformation mechanism, the simulation test, including thermal cycles of abrupt heating and quenching, was carried out. The test results indicated that the irradiated surface was heated up to about 1100ЊC and then quenched to room temperature, which was enough to obtain the surface hardening through martensitic transformation. Thermal analysis of the irradiated surface was also carried out for systematic understanding of the microstructural modification in terms of the irradiation parameters such as beam travel speed.

Correlation of Microstructure with Hardness and Wear Resistance of Carbide-Reinforced Ferrous Surface Composites Fabricated by High-Energy Electron-Beam Irradiation

“…Detailed analysis of temperature and time during the irradiation process was described in previous studies on a heat-transfer modeling. [3] In this study, process parameters were fixed at the optimal conditions established by the Budker Institute of Nuclear Physics ( Table I). The MgF 2 flux did not affect the composition of the surface composite because of no chemical reaction between flux and the substrate.…”

“…Recently, research has been conducted on ferrous surface composites in which the excellent resistance to heat, corrosion, and wear of carbides are fully utilized by direct irradiation of high-energy electron beam. [1][2][3][4] This high-energy electron-beam irradiation method can achieve required surface properties while maintaining substrate properties, because cooling rate is fast and input energy hardly affects the substrate during the irradiation. [5] Surface compositing is a fabrication method in which hardness, wear resistance, and thermal resistance can be enhanced by depositing desired elements on a substrate to form a composite layer.…”

“…[9][10][11] For the fabrication of the surface composites through surface melting, a flux has to be used to protect melted carbide powders and substrate from the air and to promote homogeneous melting. [2,3,12] Microstructure, hardness, and wear properties of the three ferrous surface composites were comparatively analyzed to understand the mechanisms of the surface property improvement. In particular, the property improvement DUKHYUN September 13, 2008 in the composite fabricated with TiC and Cr 3 C 2 powders in comparison to the composites fabricated with TiC or Cr 3 C 2 powders was verified.…”

Surface hardening of a gray cast iron used for a diesel engine cylinder block using high-energy electron beam irradiation

“…[11,12,13] ysis was conducted to calculate the temperature distribution, Recently, a high-energy electron-beam (energy range: 0.5 including peak temperature, cooling rate, and irradiation to 1.5 MeV) irradiation technique, which can be extracted into air, has been developed. [14,15,16] A high-energy electron depth. To verify the applicability of this model, a thermal beam can penetrate up to several tens of centimeters of air.…”

Effects of Tempering on Microstructure, Hardness, Wear Resistance, and Fracture Toughness of Cr3C2/Steel Surface Composites Fabricated by High-Energy Electron-Beam Irradiation

“…[7][8][9] In order to remove this residual stress, the subsequent heat treatment, such as tempering, is needed as in fusion welded regions. [10][11][12] In addition, because the matrix of the surface composite layer is generally composed of bainite or martensite due to rapid cooling, it is difficult for steel-based surface composites to be applied to areas requiring high fracture toughness. Proper combination of hardness and fracture toughness, together with the secondary hardening effect of alloy carbide precipitates, can also be achieved by the tempering.…”