Hypereutectic high-chromium white cast iron and preparation method thereof

Abstract

The invention relates to a hypereutectic high-chromium white cast iron, which comprises the following components by mass percentage: 3.2-4.5% of C, 25-30% of Cr, 0.4-1.0% of Si, 0.4-1.0% of Mn, 1.5-3.0% of Ti, 3.5-5.0% of W, less than or equal to 0.04% of P and S, 0.02-0.05% of Al, 0.1-0.3% of Y, and the balance of Fe. A preparation method of the hypereutectic high-chromium white cast iron comprises the following steps: adding waste iron, pig iron and high carbon ferro-chrome in an intermediate frequency induction furnace with a vacuum system for melting, pre-deoxidizing ferrosilicon and ferromanganese, deoxidizing by using aluminium wire; adding ferrotungsten and ferrotitanium, vacuumizing, placing yttrium at bottom of ladle, dumping molten iron in the ladle, removing slag; when temperature of molten iron is reduced, pouring sand mold to obtain the hypereutectic high-chromium white cast iron; quenching, tempering, and discharging and cooling. The hardness HRC of the hypereutectic high-chromium white cast iron is 64-68, and the impact toughness is greater than 7J / CM<2>.

Description

technical field [0001] The invention relates to a cast iron and a preparation method thereof. Background technique [0002] The production and application of high-chromium cast iron as a wear-resistant and corrosion-resistant material has developed rapidly, because high-chromium cast iron contains a large amount of high hardness M 7 C 3 It has excellent wear resistance, and the chromium element dissolved in the matrix can improve the corrosion resistance of the material. So far, it has become the most widely used wear-resistant and corrosion-resistant cast iron in the world. In industrial applications, high-chromium cast iron often adopts hypoeutectic or near-eutectic components with a chromium content of 15-25% and a carbon content of 2.0-3.0%. Due to the low content of carbides, in many wear-resistant and corrosion-resistant working conditions, such as vertical mill rollers, slurry conveying impurity pumps, ball mill liners, etc., the wear resistance is obviously insuffi...

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Problems solved by technology

The material uses tungsten, nitrogen, niobium, boron, and rare earth elements to achieve fine carbides, but the amount of tungsten added is less than 3.5%, and it exists in the matrix and M in solid solution form. 7 C 3 Among carbides, hypereutectic high chromium cast iron does not have new phases, such as WC, W 2 The existence of C phase indicates that less than 3.5% of tungsten has limited effect on the refinement of hypereutectic high chromium cast iron structure, adding nitrogen and high chromium cast iron has low toughness, and at the same time, pores are easy to occur in castings

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