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

Abstract

This study investigates the effects of high-energy electron-beam (1.4 MeV) irradiation on surface hardening and microstructural modification in a gray cast iron currently used for a diesel engine cylinder block. The gray cast-iron samples were irradiated in air using an electron accelerator. Afterward, their microstructure, hardness, and wear properties were examined. The original microstructure, which contained graphite flakes in a pearlitic matrix, was changed to martensite, ledeburite, and retained austenite, along with complete or partial dissolution of the graphite. This microstructural modification occurred only when the surface was irradiated with an input-energy density over 1.1 kJ/cm 2 , and it greatly improved the surface hardness and wear resistance. In order to investigate the complex microstructures, thermal analysis and simulation testing were also carried out. The results indicated that the irradiated surface was heated to the austenite-temperature region and then quenched to room temperature, which was enough to obtain surface hardening through martensitic transformation. The thermal analysis results matched well with the microstructures of the thermally simulated samples.

Property improvement of stainless-steel-base surface composites fabricated by high-energy electron-beam irradiation

“…SiC is a stable and hard compound having a density of 3.22 g/cm 3 , and a melting temperature of 2760 ºC [8]. An AISI 304 stainless steel plate (100 × 50 × 20 mm 3 ) was used as a substrate, and its chemi- The surface composite specimens were sectioned parallel to the irradiation direction, polished, and electro-etched at 1.5 V in a solution of H 2 O 100 ml + HNO 3 100 ml [9]. The microstructure was observed by an optical microscope and a scanning electron microscope (SEM).…”

“…Recently, new attempts have been made by direct irradiation using a high-energy electron beam to improve hardness and wear resistance of the metal surface via surface hardening or surface alloying [3,4]. Transition metals usually form carbides such as TiC and Cr 23 C 6 in steels when combined with carbon, and these carbides can be used as reinforcing or coating materials because they have very high hardness and excellent wear resistance [5,6].…”

Correlation of microstructure and wear resistance of molybdenum blend coatings fabricated by atmospheric plasma spraying

“…The plasma spraying method is the most economical and effective method applied to automotive parts, such as cylinder bores, synchronizer rings, crankshafts, and piston rings, in order to reduce their surface degradation [1][2][3].…”

Correlation of microstructure and wear resistance of ferrous coatings fabricated by atmospheric plasma spraying

“…Their microstructures, hardness, and wear ing attention. [1][2][3][4][5][6][7][8][9][10] resistance were investigated to understand the mechanism Plasma spraying is most widely applied in automotive involved in the formation of coatings and to elucidate the industries among thermal spraying methods because (1) it correlation of microstructures with wear properties of coatis less restricted in material selection; (2) it has higher spray ings and counterpart materials. rate and deposition efficiency than high velocity oxyfuel process, flame spraying, and electric arc spraying; ( wt pct Al 2 O 3 ϩ 40 wt pct ZrO 2 ) are also used in order to improve the wear resistance of the ferrous coatings.…”

“…To prevent overheating in specimens during spraying, a specimen holder was cooled pct Al 2 O 3 -ZrO 2 powders are hereinafter referred to as "A0," with compressed air, and the traverse speed of a spraying defects formed during casting, and MnS inclusions hardly affect properties of the cast iron. [9] gun was maintained constant. Detailed plasma spraying conditions are listed in Table III. A gray cast iron (FCH2D), which was completely finished C. Microstructural Analysis and Hardness Test as a diesel engine cylinder bore (chemical composition: Fe-3.54C-2.21Si-0.674Mn-0.025Cr-0.013Cu-0.056P-0.031S…”