Research and features of preliminary graphitizing processing of melt of iron with silicon carbide on the structure and properties of cast iron castings

Abstract

The materials used for preliminary graphitizing treatment of cast iron melt (pre-modification), of which silicon carbide has the greatest technical and economic advantage, are considered. The features of the graphitizing effect of silicon carbide during the preparation of a gray cast iron melt on its structure and properties in standard cylindrical samples and clutch plate castings are analyzed. It is shown that its graphitizing effect on the cast iron melt begins to partially manifest itself already at the stage of introduction into the furnace and enhances the action of the main graphitizing modifier during subsequent ladle treatment as a result of a decrease in the content of interdendritic graphite in the microstructure.

Technology for producing cast iron castings with compact graphite by top filling

“…In particular, castings from low grades of high-strength cast iron (ChVG40, VCh50), having less stringent requirements for microstructure and properties (the predominance of the ferrite component of the structure and SSG ≥ 80% [5][6][7]), can be obtained in a somewhat simplified manner both in terms of labor intensity, and the complexity of the equipment and technology used. The most widespread and well-proven in practice "sandwich" process in an open ladle can be used to modify high-strength cast iron only in ladles with a height to average diameter ratio of 2...2.5:1 [8,9]. Pouring ladles with a metal capacity of 1.2 tons used in iron foundries have a height to average diameter ratio of 1.4:1 [10,11].…”

The Improvement of the Operational Characteristics of the Ventilated Front Brake Discs

“…These are caused by the high contact pressures (up to 10 MPa) and intense frictional heating (up to 600 ° C), regarding dry abrasive friction [1][2][3][4]. An obstacle to further optimization of the materials in the manufacture of the "brake disc -pad" pair is the lack or insufficient information on the influence of the composition and technological factors on the operational properties of the friction pair parts, as well as the information on the mechanisms of friction and wear in the "brake disc -pad" pair [5][6][7][8][9]. The purpose of the work is the improvement of the operational characteristics of ventilated front brake discs by changing the composition of the material used for their manufacture (gray pearlitic cast iron Gh190).…”

Structural Features and Distribution of Silicon in Ferrosilicon-Magnesium Modifiers

“…In world practice, the vast majority of modifiers for spheroidizing ladle and in-mold processing of a melt of ductile iron with spheroidal and vermicular graphite are made on the basis of FS45 ferrosilicon with a Si content of 44-48% [1][2][3][4][5][6][7][8]. Traditionally, domestic and foreign manufacturers receive modifiers in the form of a thin ingot 4-35 mm thick [9][10][11], however, there is also a technology for the manufacture of modifiers in the form of ultra-thin plates − chips with a thickness of 0.5-3 mm by continuous casting of the melt and its crystallization on steel water-cooled drums [12] (Fig.…”