SU765366A1 - Method of blasting cast iron preparation for casting thin-wall ingots - Google Patents

Description

one

The invention relates to metallurgy, namely, foundry, and can be used to produce thin-walled castings from blast furnace of the first heat. five

There is a known method of preparing first-blast-iron for smelting molds, which includes chemical composition finishing with ferroalloys, holding in a mixer and pouring into a pouring ladle. and poured onto a metal mirror in a mixer. 5 Exposure before casting into molds produced within 1-2 hours

The disadvantage of this method is the unsatisfactory density and low strength properties of cast iron, 20 due to the unfavorable shape of graphite inclusions and a slight degree of purification from harmful trace impurities of non-ferrous metals from ores. Therefore, this method 25 is not suitable for preparing the first-cast iron for the casting of thin-walled castings.

The aim of the invention is to increase the density and strength of metal AOR

castings by improving the structure of cast iron and reducing the content of harmful trace impurities.

This is achieved by extracting the metal in the mixer for 3-50 hours, pouring over the pouring ladle, at the bottom of which a rare-metal ligature is pre-introduced in an amount of 0.025-3.0 wt.% Of the weight of the liquid metal, at a temperature of 1360-1500 ° С, and after settling in the ladle for 2-10 minutes, the metal is poured into casting molds.

In the process of long aging of the pig iron in the mixer, a sang also emerges in the form of large non-metallic inclusions, accompanied by cleaning the metal from harmful trace impurities of non-ferrous metals. The shutter speed can be combined with the transportation of metal from blast furnaces to foundries. Improve the shape of the graphite inclusions and the structure of the matrix reach additional processing meta.pla rare metal ligature in the casting ladle immediately before pouring.

The method is designed to produce high-quality thin-walled diets from liquid first-time cast iron of the first melt.

The method is carried out as follows. Hves radiator sections are obtained. 8 kg, BOO size) 150x 100 mm, average wall thickness 5 mm. The temperature of release of cast iron. Correct the chemical composition by introducing ferrosilicon and ferromanganese into the ladle.

. After prolonged soaking in the mixer and treating with a raremeach ligature, the content of harmful trace impurities of colored metals in the cast iron decreases by 5-10 times, the dispersion of perlite increases, the length decreases and the shape of graphite inclusions improves, the density increases by 3-6%, the strength increases to 4 times.

The optimal duration of the iron exposure in the mixer is 3-50 hours. Reducing the output for less than 3 hours worsens the assimilation stability and uniform distribution of silicon and manganese in the iron with decreasing exposure over 50 hours, the temperature of the metal is significantly reduced and additional heating is required before pouring it into the casting tank. ladle.

The optimum temperature of the metal during pouring into the casting ladle is 1360-1500 ° C. As the temperature decreases, the fluidity of the metal, solubility and absorption of the rare metal alloy are less impaired, and with increasing temperature, oxidation and irreversible loss of the alloy are increased. The optimal processing time of the cast iron with a rare metal ligature in the casting ladle is 2-10 minutes. With a decrease in duration of less than 2 minutes, the absorption of ligatum 1 l is impaired, with an increase in duration of more than 10 minutes, the refining effect decreases.

The selection of the optimal technological parameters of the method is carried out on the basis of experimental data obtained during the production of radiator castings, sections, from liquid pig iron.

After finishing the chemical composition with ferrosilicon and ferromanganese, the cast iron is kept in a mixer for any period of time and poured at a different temperature into the casting ladle. At the bottom of the bottling bucket placed the rare metal ligature on

5 iron-silicon base containing 20-30% of rare-earth metals. After aging, the cast iron is poured into sand molds for the radiator sections.

The physicomechanical properties of the samples are given in the table.

Ionic effect is 40-60 rubles. per 1 ton of casting by reducing metal losses, saving coke, fluxes, refractories and other materials.

The duration of the exposure of cast iron in the mixer, h

Pig iron temperature at overflow into casting ladle, with

10 16 18 17

22 34 36 35

Low fluidity, adhesions, underfill

18 32 35 34

8 15 17 16

Low fluidity, adhesions, underfill

Properties of cast iron without processing rare metal ligature

The duration of iron exposure in the mixer is 23.5 hours, the temperature of cast iron at overflow into the casting ladle is 1430 ° C, the amount of rare metal master alloy is 1.5 wt.%

  The duration of the exposure of cast iron in the mixer is 23.5 hours, the temperature of the cast iron during overflow into the casting ladle, the duration of holding in the bottling ladle after treatment with a rare-metal ligature is 6 min.

Claims (1)

1. Foundry production. 1976, I 2, p. 17