SU1673247A1 - Method of producing modified water-glass binder for casting moulds and cores - Google Patents

Abstract

The invention relates to a foundry and can be used to prepare a liquid glass binder used to make foundry molds and cores. The purpose of the invention is to improve the physical and mechanical properties of the forms and cores and to improve their knockability. The method of preparing a modified liquid glass binder for the manufacture of casting molds and cores consists in the fact that water glass is pretreated by ultrasound in the range of 25-35 kHz for 7-15 minutes, after which electro-hydraulic treatment is performed with pulsed electric discharges in an amount of 15-25 impulses with an energy of one impulse of 0.65 - 0.75 kJ per 1 kg of binder. In this case, carbon black is used as a modifying agent for liquid glass. The treatment of liquid glass with ultrasound and electrohydraulic pulses in combination with a modifying additive helps to improve the adhesive strength of the binder, reduce crumbling, and improve embossability. 1 hp f-ly, 2 tab.

Description

The invention relates to foundry and can be used to prepare a liquid glass binder used to make foundry molds and cores.

The purpose of the invention is to improve the physicomechanical properties of the forms and cores and to improve their knockability.

The essence of the invention lies in the method of preparation of the modified liquid glass binder, which consists in the fact that water glass is pretreated with ultrasound in the range of 25-35 kHz for 7-15 minutes, after which it is electrically processed by pulsed

electric discharges in the amount of 15–25 pulses at an energy of one pulse of 0.65–0.75 kJ per 1 kg of binder. In this case, the modification of liquid glass is carried out with carbon black.

The method for preparing the modified liquid glass binder for making the casting molds and cores is carried out as follows.

In the 10/1 standard ultrasonic installation chamber UZVD-6, 10 parts of liquid glass (tons 2.8 at 1420) kg / m3 and 1 part of carbon black according to GOST 7885-86 are supplied. After that, the resulting suspension is sonicated in the range of 20-35 kHz for 7-15 minutes.

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Under the action of ultrasound in the above range, carbon black granules are impregnated with liquid glass. As a result, these granules are no longer isolated lumps of carbon suspended in liquid glass, but clots (zones) of increased carbon concentration impregnated with liquid glass.

After the ultrasonic action, the obtained mass is pulsed by high-voltage electric discharges, 15–25 pulses at an energy of one pulse of 0.65–0.75 kJ per

1 kg of binder, in a discharge chamber made of steel 20, in which vacuum rubber or polyethylene serves as the electrical insulation of the electrodes. As the generator of current pulses (HIT with a control panel) use the HIT of Strike 30 installation.

The high-voltage discharge is accompanied by a powerful compression wave, high-speed hydraulic flow and cavitation effects leading to the destruction of the above clots (dislocations) of carbon black and its uniform distribution over the entire volume of the mixture being processed.

Table 1 shows the composition of the mixture prepared with carbon black, table 2 shows the parameters of ultrasonic and electrohydraulic treatment and the properties of this mixture.

For the tests in a laboratory mixer, a molding mixture was prepared. First, the dry components of the mixture are mixed for 1 min, after which the modified technical carbon glass is introduced and the mixture is stirred for

2 minutes. An example of the chemical and quantitative composition of the mixture is listed in Table 1.

In determining the strength, flaking ability and gas permeability, the standard procedure was used. Work knockout was estimated by the method of TsNIITMASH. Samples were placed in a mold and poured with steel 35 at 1680 ° C. the temperature in the center of the samples was 1000-1200 ° C. Table 2 shows the results of the tests.

As can be seen from the above results, the treatment of liquid glass, in the process of modifying with technical carbon, ultrasound, followed by electrohydraulic treatment within the proposed limits of the modes of the mentioned operations, can significantly improve parameters such as strength, flaking, vitality, and also facilitate their knockability.

Claims (2)

1. A method for preparing a modified liquid glass binder for manufacturing casting molds and cores, including electrophysical treatment of liquid glass with pulsed electrical discharges during its modification with a technological additive, characterized in that, in order to improve the physical and mechanical properties of the molds and cores and improve their knockout , the liquid glass is pretreated with ultrasound in the range of 25-35 kHz for 7-15 minutes, and the electrohydraulic treatment is carried out by pulsed electro nical bits of 15-25 in an amount of pulse energy at one pulse 0.65-0.75 kJ per 1 kg of the binder. 2. A method according to claim 1, characterized in that carbon black is used as a modifying processing additive for liquid glass. Nfc The content of the ingredients of the mixture, wt.% Formed quartz sand brand 1 K02 Modified liquid glass binder: liquid glass m - 2.4; y - 1420 kg / m surfactant, lighoculphonate technical grade B technical carbon according to GOST 7885-86 CO carbon dioxide Table 1 amount 100 7 5,0 1.4 0.6 Blowing at P -2.0 kg / cm2 t -1 min table 2