Chromium-niobium-boron alloy rare earth casting grinding ball and production process method thereof

Abstract

The invention relates to a chromium-niobium-boron alloy rare earth casting grinding ball and a preparation method thereof. The casting grinding ball comprises the following chemical components in percentage by weight: 1.3 to 3.0 percent of carbon, 0.3 to 1.2 percent of silicon, 0.2 to 1.0 percent of manganese, 4.0 to 7.5 percent of chromium, 0.03 to 0.10 percent of niobium, 0.01 to 0.2 percent of boron, less than or equal to 0.10 percent of phosphorus, less than or equal to 0.10 percent of sulphur, 0.15 to 0.3 percent of composite rare earth leavening agent and 86.5 to 93.81 percent of iron. The method comprises the following production operation steps of: smelting, casting, performing heat treatment, and performing mechanical property detection and whipping detection, wherein the heat treatment comprises austenization treatment, oil quenching treatment and low-temperature tempering treatment. The austenization treatment comprises the following four stages that: the temperature of the first stage is 350 DEG C and is kept for 2 hours; the temperature of the second stage is 550 DEG C and is kept for 2 hours; the temperature of the third stage is 800 DEG C and is kept for 2.5 hours; and the temperature of the fourth stage is between 930 and 980 DEG C and is kept for 2.5 hours, wherein the quenching oil temperature is between 50 and 140 DEG C; the quenching time is between 6 and 20 minutes; the low-temperature tempering temperature is between 210 and 280 DEG C; and the tempering time is 8 hours. The hardness of the grinding ball reaches HRc 60 to 64, and the impact toughness is higher than 4 J / cm<2>. The manufacturing cost of the grinding ball is further lowered without the usage of rare and precious metal elements such as molybdenum, nickel, copper, titanium, vanadium, copper and the like.

Description

technical field [0001] The invention relates to a metal grinding medium widely used in powder engineering in metallurgical mines, thermal power energy, building materials, cement, engineering machinery and other industries, namely a chromium-niobium-boron alloy rare earth cast grinding ball and a production process thereof. Background technique [0002] As a grinding medium, grinding balls are widely used in powder engineering in industries such as mining metallurgy, energy thermal power, non-metal processing, building materials, cement, coal-water slurry, and magnetic materials. Due to the need to meet the requirements of different equipment and different working conditions in various industries, the materials for manufacturing grinding balls are various, such as forged steel balls, nodular cast iron grinding balls, chromium alloy casting grinding balls, etc., and the specifications also range from ?6mm to ?150mm. even larger diameters. [0003] Chromium alloy cast grindin...

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Problems solved by technology

[0007] However, the above two patents still have certain limitations in production practice. First, although the amount of chromium used is reduced (the chromium content of superhard high-chromium grinding balls is less than or equal to 10%, high-carbon multi-element alloy casting The chromium element content of the grinding ball is less than or equal to 6%

), but still need to add a small amount of rare and precious metal elements such as molybdenum, nickel, titanium, vanadium, copper, etc., which increases the manufacturing cost of grinding ball products; second, it is difficult to master the micro-alloying technology, otherwise the loss of alloying elements will be large during the smelting process

The third is that the process is complicated, and the investment in related production equipment is relatively high, so it is difficult for ordinary scale enterprises to implement

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