Effect of Mechanical Vibration on Microstructure and Mechanical Properties of Gray Cast Iron in Lost Foam Casting

Abstract

In order to reveal the effect of vibration solidification on microstructure and properties of gray cast iron in lost foam casting, Y-shaped HT100 gray cast iron was prepared by vibration lost foam casting, and the effect of amplitude on the microstructure and properties of gray cast iron was studied. The results showed that, with the increase in amplitude, the short and thin A-type flake graphite increases, and the austenite structure transforms from columnar to cellular. The hardness, tensile strength, and elongation of gray cast iron first increase and then decrease with the increase in amplitude. The appropriate amplitude in the process of Y-shaped HT100 gray cast iron by lost foam casting is 2 mm, while the tensile strength and elongation of gray cast iron are the highest, with the values of 147.51 MPa and 1.17%, respectively. The change of mechanical properties of gray cast iron is mainly determined by the morphology and distribution of austenite in gray cast iron and A-type flake graphite.

Improvements in Wear and Corrosion Resistance of Ti-W-Alloyed Gray Cast Iron by Tailoring Its Microstructural Properties

“…The XRD spectrum of Sample B-1 showed one large and narrow intensity peak at 44.74°, presenting an austenite phase, and two more intensity peaks at 65.06° and 24.12°, presenting α-Fe (α-ferrite) and Fe3C (graphite) phases with the bod-centered cubic (BBC) in Sample B-1. Conversely, Samples B-2, B-3, The graphite flakes were classified as B-type, which are more rounded and refined, whereas D-type class graphite flakes develop under rapid cooling and tend to cluster in rosette-like patterns [47][48][49][50]. The E-type graphite flakes were very tiny and unevenly formed as a result of extremely rapid cooling rates combined with the significant carbideforming activity of titanium and tungsten [50].…”

“…The other alloying element W refines the grain size and promotes pearlite in cast alloys [45,46]. The graphite flakes were classified as B-type, which are more rounded and refined, whereas D-type class graphite flakes develop under rapid cooling and tend to cluster in rosette-like patterns [47][48][49][50]. The E-type graphite flakes were very tiny and unevenly formed as a result of extremely rapid cooling rates combined with the significant carbideforming activity of titanium and tungsten [50].…”

Titanium Carbide and Vibration Effect on the Structure and Mechanical Properties of Medium-Carbon Alloy Steel

“…It was found that, due to the effect of vibration during the solidification of the casting, the flow of the metal melt accelerates, the temperature gradient of the metal melt decreases, and fluctuations in the concentration of carbon atoms occur, which contributes to the homogenization of the composition of the metal melt so that the germ-like flake graphite cannot grow, and as a result, a flake of graphite of shorter length and smaller thickness is formed. Vibration treatment led to an increase in hardness, tensile strength, and elongation of gray cast iron after destruction [27]. It was found that, at a vibration frequency of 35 Hz, the microstructure of gray cast iron is denser than that of a sample without vibration, flake graphite of type A becomes thinner and shorter, and the effect of refining primary austenite is very obvious.…”

“…The physical and mechanical characteristics of the metal changed significantly. The central porosity decreased by [25][26][27][28][29][30][31][32][33][34][35][36].7%, the total chemical heterogeneity by 39.8-75%, liquation and total fracturing by 34-100%, the zone of equiaxed crystals increased by 26.5-35%, and the mechanical characteristics of the metal (tensile strength and yield strength, elongation and compression) increased by 5.5-19%. Castings from GX120Mn13 steel were obtained, which were cast into sand molds at atmospheric pressure using powder modifiers in the form of a TiN+Cr composition.…”

“…Research on the effects of vibration on crystallizing melts is mainly focused on aluminum, siliceous, and magnesium cast alloys [16][17][18][19][20][21][22][23][24][25][26]. Although the positive effect of vibration treatment on cast products made of iron-carbon alloys has been shown in the technology of production of castings according to smelted models [27,28], no scientific papers have been found to study the effect of vibration on the structure and properties of cast steel alloys.…”