SU585220A1 - Method of refining metal melts - Google Patents

Description

I. .

The invention relates to foundry production, in particular to methods for refining metals and alloys, and will find wide application in the manufacture of shaped parts by casting.

The known method of refining. metals and alloys in molds With this method, synthetic (plan and deoxidizers are introduced directly in the process of pouring metals and alloys into a mold.

The disadvantage of this method is the possibility of oxidizing the liquid metal during the formation of HCl and the low plastic properties of the melts.

The purpose of the invention is to reduce the oxidation of the melt in the process of forming, casting and increasing the plastic c & octv of the melt.

This is achieved by introducing deoxidizing agents into the liquid melt and feeding slag-forming material onto its surface directly after pouring the melt into a mold heated to a temperature not lower than the liquidus temperature of the alloy, followed by aging under the slag during casting process.

2

The method is carried out as follows.

The ceramic form after iarpe in the furnace (for example, induction with a graphite heat radiator) to a temperature not lower than the liquidus temperature of the cast alloy is installed on the water-cooled crystallizer and agsivayut steel through the hole in the crake. ovens. The steel is smelted in a separate smelting (open) furnace in the usual manner with deep deoxidation. Zalivak1T steel from crucible melting furnace; or with the help of a ladle, after that, a deoxidizer (for example, mischmetall) is cast into the melt. The deoxidizer is introduced on the rod under the melt mirror in the profit zone. Then they pour it into the melt mirror: a mixture of mo – lot fluorspar, lime and silicocalcium. The casting mold is cooled from the bottom upwards with an adjustable speed (the crystallizer when you gradually remove it from the furnace heating zone. The metal in the mold that is in the area of the furnace heater is kept in a liquid state until it is completely solidified from the casting.

An example. Ceramic forms (shells) are made on an electrocorundum base and using melted models. Forms calcined without filler at 900 ° C for 3-4 hours. in the proksgovochnoy furnace. The cooled shells are alternately mounted on the mold and molded with electrocorundum in a graphite cylinder that serves as a radiator in the heating process. The mold in the middle and upper part (in height) is heated in an induction furnace to 1400-1450 ° C and poured with stash through a filling funnel in the lid of the heating furnace.

The steel is smelted in a base lined induction furnace.

Chemical composition of steel,%;

0.07 14.5 7.5 0.7 0.4 0.9 0.025 Deacidification (deep) was made by ferromanganese. Ferrosilicium and silicocalcium in quantity O, 35; 0.1 and 0.1% of the weight of the mixture, respectively. during the smelting process, slag of the following composition is applied, weight. %: Fluorspar 15 Lime82 Magnesite3 Steel is poured at a temperature from a 1-piece ladle. After the steel has been poured into the mold, it is introduced into the melt with the help of a silicocalcium bell in an amount of 0.1% of the weight of the poured metallite, 1 b / kg. Immediately after the steel deoxidation, a powdery slag mixture of the following composition is added to the melt mirror in the pot; the powdered slag mixture of the following composition is wt.%:

The amount of slag mixture was 2% by weight of the poured metal.

Cooling of the cast mold is carried out from bottom to top with a mold with the gradual removal of the mold down from the heating zone of the furnace at a speed of 12 mm / min. The duration of the mold is 25 min.

The inclusions are evenly distributed in the metal and have a rounded appearance. (The largest size of inclusions is 0 1.05 mm. The oxygen content in steel, determined by the method of vacuum plasma, is (weight%) 50.0174 0.0215 mm; in samples from the smelting furnace, 0.021-0.093 in samples from castings, subjected to refining in form, and 0.03370, 0420 in samples from castings without refining into shapes.

Claims (1)

The deacidification in the form lowers the oxygen content in the steel that has oxidized when it is cast, and prevents the steel from being oxygenated during the solidification of the casting. The invention of the method of refining metal melts by introducing deoxidizers into the liquid melt and feeding a slag-forming mixture onto its surface, so that it is used to reduce the oxidation of the liquid melt during the formation of the casting and plasticization of the melts, the introduction of deoxidizers and the supply of the ash mix are produced in a heated to i temperature, not lower than the liquidus temperature, after pouring the melt with its subsequent aging under the donkey during solidification livki. Sources of information taken into account in the examination: 1. USSR Copyright Certificate 311698, cl. B 22 D 7/00, 1969.