CN1323184C - Rare earth silicon bismuth cerium alloy and its production process - Google Patents

Abstract

A rare earth silicon bismuth cerium alloy, Si 68-75%, Bi 0.3-2.0%, Ce 0.1-1.0%, Ca 1.0-2.0%, Al≤0.9%, Fe balance. The production process is as follows: adding raw materials such as silica, rare earth concentrate, coke, and steel shavings to the submerged arc furnace according to the weight ratio for smelting; melting silicon-calcium alloy, ferrosilicon alloy, and metal bismuth in the medium-frequency induction furnace according to the weight ratio. First add the alloy melt in the submerged arc furnace into the alloy bag, and then feed the cored wire head containing the scraps of rare earth silicon-bismuth-cerium alloy into the alloy bag to feed the wire at a constant speed; while feeding the wire, the silicon-bismuth-calcium alloy of the intermediate frequency furnace The ratio is added, and the reaction is carried out under the protection of nitrogen; the alloy melt is injected into a mold, cooled, crushed, and sieved to obtain the rare earth silicon bismuth cerium alloy. The invention rationally arranges the anti-spheroidizing element Bi and the spheroidizing element rare earth, can effectively increase the number of graphite balls in ductile iron castings, and reduce the phenomenon of graphite distortion, aggregation, floating and fast decay, and can be used as an inoculant for large-section ductile iron castings Use can significantly improve its quality.

Description

Rare earth silicon bismuth cerium alloy and its production process

technical field

The invention belongs to the inoculant used in the foundry industry, and in particular relates to a rare earth silicon bismuth cerium alloy produced by adopting hydrothermal combined production and feeding line method and a production process thereof.

Background technique

At present, the inoculants used in my country's malleable cast iron mainly include high-silicon plus bismuth, such as BaCl2-Al-Bi, SrCl2-Al-Bi, RESi-Bi and other inoculants. The use of these inoculants is prone to graphite in the production of large-section ductile iron Distortion, graphite aggregation and floating, and rapid decay make it difficult to guarantee the quality of large-section ductile iron castings.

Contents of the invention

The object of the present invention is to aim at the deficiencies in the prior art, rationally arrange the anti-spheroidizing element Bi and the spheroidizing element rare earth in the inoculant, and provide a novel inoculant rare earth silicon-bismuth-cerium alloy. In the production of ductile iron casting, the use of rare earth silicon-bismuth-cerium alloy can effectively increase the number of graphite balls, reduce graphite distortion, and improve the quality of large-section ductile iron castings.

The technical solution of the present invention is: Si 68-75%, Bi 0.3-2.0%, Ce 0.1-1.0%, Ca 1.0-2.0%, Al≤0.9%, Fe balance in the rare earth silicon bismuth cerium alloy.

The present invention adopts hydrothermal cogeneration and feed line method to produce rare earth silicon bismuth cerium alloy, and its production process is:

Mix raw materials such as silica, rare earth concentrate, coke, and steel shavings according to the weight ratio of 1.5-2.0:0.01-0.4:1.0-1.4:0.2-0.4, and continuously add them into the submerged arc furnace, and guide the current into the melting charge through self-baking electrodes For smelting, the furnace temperature is controlled at 1500-1600°C; silicon-calcium alloy, ferrosilicon alloy, and metal bismuth are mixed evenly according to the weight ratio of 5-20:150-200:3-20, and then melted in an intermediate frequency induction furnace, and the furnace temperature is controlled At 1500-1700°C; first add the molten alloy in the submerged arc furnace into the alloy ladle, then feed the cored wire end containing the scraps of rare earth silicon-bismuth-cerium alloy into the alloy ladle, and start feeding the wire at a constant speed, and the speed of the wire feeding is controlled At 0.2-1m/s, the feeding amount is 10-20% of the melt in the submerged arc furnace; while feeding the wire, add the silicon-bismuth-calcium alloy melted in the medium-frequency induction furnace according to 10-30% of the weight of the liquid alloy in the submerged arc furnace Alloy bag, the alloy in the bag reacts under the protection of nitrogen, the reaction temperature is controlled at 1300-1500 ℃, and the time is controlled at 150-200s. The alloy melt is injected, cooled, crushed and sieved to obtain rare earth silicon bismuth cerium alloy.

In the rare earth silicon bismuth cerium alloy of the present invention, anti-spheroidizing element Bi and spheroidizing element rare earth are rationally arranged, and can be used as an inoculant for large-section ductile iron castings, which can effectively increase the number of graphite balls in ductile iron castings, reduce graphite distortion, The phenomena of aggregation, floating and fast decay have significantly improved the quality of large-section ductile iron castings. The invention adopts a new process of submerged arc furnace as the main part, intermediate frequency furnace as the supplementary part and wire feeding method as supplementary part, which can effectively utilize the leftovers of the alloy and significantly reduce the production cost.

Detailed ways

The invention adopts a 3200KVA submerged arc furnace, a 0.5T intermediate frequency induction furnace and a wire feeding machine to jointly produce the rare earth silicon bismuth cerium alloy.

Example 1:

Rare earth silicon bismuth cerium alloy product main composition requirements: Si 72-74%, Bi 0.9-1.1%, Ce 0.2-0.3%, Ca 1.4-1.6%, Al≤0.9%, Fe balance.

The production process is as follows:

1. Mix 1.90T silica, 0.015T rare earth concentrate, 1.2T coke, and 0.25T steel shavings according to the weight ratio, and continuously add them into the submerged arc furnace, control the voltage at 80-90V, and control the current at 24000-26000A , After about 180 minutes of smelting, it is ready to be released from the furnace, and the temperature of the furnace is controlled at 1500-1600 °C.

2. After the submerged arc furnace is energized for about 100 minutes, mix 10kg of calcium-silicon alloy, 1761kg of ferrosilicon alloy, and 14kg of metal bismuth into the medium-frequency induction furnace, and adjust the power to 180KW for smelting. During the melting process, the charge should be continuously pressed down to speed up the melting speed. After about 70 minutes, the charge is completely melted, and when the temperature of the molten alloy in the furnace reaches 1500-1700°C, it is ready to be released from the furnace.

3. Put the molten alloy in the submerged arc furnace into the alloy ladle and remove the slag. After the slag is removed, the temperature is controlled at 1400-1500°C, and the weight of the molten alloy is about 1.0T: put the alloy ladle into the pit, this When using a wire feeding machine, send the cored wire head containing the scraps of rare earth silicon-bismuth-cerium alloy into the alloy bag to start feeding the wire. The feeding speed is controlled at 0.5m/s, and the feeding amount is 100kg. About 200kg of silicon-bismuth-calcium alloy melt is put into the alloy ladle, and the alloy in the ladle reacts under the protection of nitrogen. The reaction temperature is controlled at 1300-1500°C, and the time is controlled at 150-200s. The alloy melt is injected, cooled, and broken and sieving to obtain rare earth silicon bismuth cerium alloy products.

After inspection, all technical indicators are in line with product quality technical requirements.

Example 2:

Rare earth silicon bismuth cerium alloy product main composition requirements: Si 68-70%, Bi 1.4-1.6%, Ce 0.5-0.7%, Ca 1.0-1.2%, Al≤0.9%, Fe balance.

The production process is as follows:

1. Mix 1.60T silica, 0.05T rare earth concentrate, 1.1T coke, and 0.3T steel shavings according to the weight ratio, and continuously add them into the submerged arc furnace, control the voltage at 80-90V, and control the current at 24000-26000A , After about 180 minutes of smelting, it is ready to be released from the furnace, and the temperature of the furnace is controlled at 1500-1600 °C.

2. After the submerged arc furnace is energized for about 100 minutes, mix 5kg of calcium-silicon alloy, 175kg of ferrosilicon alloy, and 20kg of metal bismuth into the medium-frequency induction furnace, and adjust the power to 180KW for smelting. During the melting process, the charge should be continuously pressed down to speed up the melting speed. After about 70 minutes, the charge is completely melted, and when the temperature of the molten alloy in the furnace reaches 1500-1700°C, it is ready to be released from the furnace.

3. Put the molten alloy in the submerged arc furnace into the alloy ladle and remove the slag. After the slag is removed, the temperature is controlled at 1400-1500°C, and the weight of the molten alloy is about 1.0T: put the alloy ladle into the pit, this When using a wire feeding machine, send the cored wire head containing the scraps of rare earth silicon-bismuth-cerium alloy into the alloy bag to start feeding the wire. The feeding speed is controlled at 0.5m/s, and the feeding amount is 100kg. About 200kg of silicon-bismuth-calcium alloy melt is put into the alloy ladle, and the alloy in the ladle reacts under the protection of nitrogen. The reaction temperature is controlled at 1300-1500°C, and the time is controlled at 150-200s. points, that is, rare earth silicon bismuth cerium alloy products.

After inspection, all technical indicators are in line with product quality technical requirements.

Claims (2)

1, a kind of rare earth calcium magnesium silicon iron alloy, Si 68-75%, Bi 0.3-2.0%, Ce 0.1-1.0%, Ca1.0-2.0%, Al≤0.9%, Fe surplus.

2, the production technique of rare earth calcium magnesium silicon iron alloy according to claim 1, it is characterized in that material silex, rare earth ore concentrate, coke, steel cuttings according to weight proportion 1.5-2.0: 0.01-0.4: 1.0-1.4: 0.2-0.4 mixes, add in the hot stove in ore deposit continuously, by self baking electrode electric current is imported melting batch and smelt, tapping temperature is controlled at 1500～1600 ℃; Silicocalcium, ferro-silicon, bismuth metal are mixed the back according to weight proportion 5-20: 150-200: 3-20 melt in medium-frequency induction furnace, tapping temperature is controlled at 1500～1700 ℃; Earlier the alloy liquation in the hot stove in ore deposit is added the alloy bag, the cored-wire head that the rare earth calcium magnesium silicon iron alloy tankage will be housed is again sent in the alloy bag, begins at the uniform velocity line feeding, and wire-feeding velocity is controlled at 0.2～1m/s, and feed quantity is the 10-20% of the hot stove liquation in ore deposit; Silicon-bismuth-calcium alloy with the medium-frequency induction furnace fusing in line feeding adds the alloy bag according to 10～30% of ore deposit hot stove liquid alloy weight; alloy in the bag reacts under nitrogen protection; temperature of reaction is controlled at 1300～1500 ℃; time is controlled at 150～200s; with alloy liquation injection molding, cooling, fragmentation, screening, promptly get rare earth calcium magnesium silicon iron alloy.