SU1560368A1 - Method of top pouring steel into metal ingot moulds - Google Patents

Abstract

The invention relates to foundry, in particular, to the technology of casting steel from above. The purpose of the invention is to improve the quality of the ingot surface. Steel was poured into metal molds from above with a speed (V, m / min) of filling the mold, equal to V = 26.7-29.0 / ΔT, where ΔT is the steel overheating above the liquidus point in the mold, equal to 35-50 ° C . The implementation of the invention also makes it possible to improve the quality of the blanks obtained from ingots by hot deformation.

Description

The invention relates to foundry, in particular, to technology for casting steel from above.

The purpose of the invention is to improve the quality of the ingot surface.

Example. For each steel grade and steelmaking tooling (ladle, mold, etc.), the temperature of the start of casting steel in the ladle is determined in advance, which should provide for overheating of the steel poured into the mold above the liquidus point within 35-50 C. determined from the ratio:

26.7 - 29.0 .- v. ..t

where v is the mold filling rate, m / min;

t - steel overheating above the liquidus in the mold, equal to 35-50 C.

In the proposed method, steel 34XH1M was cast from a ladle

with a capacity of 30 tons. In the cast-iron molds, ingots with various dimensions and a mass of 3.35-6.5 tons were cast. The casting was carried out from the top through intermediate crowns with an outlet diameter of 4Q-60 mm. The liquidus temperature for steel 34XH1M was determined on a high-temperature microscope

NM-4. Experimentally, we determined the temperature at which the steel began to be cast in a ladle, which, for ingots of the indicated mass (3.35-6.5 t), provides for overheating of the steel poured into the mold within 35-50 ° C. The temperature of the start of steel casting in the ladle was determined by special tables. The temperature of the steel poured into the mold was measured in the profit of the ingot 5-10 s after it was filled with metal. Measurements were made at a distance of 150–160 mm from the mirror of the metal poured into the profit, the measuring point was located on the profit axis of the ingot. Overheating flooded in

SP

&

with

C & 00

the metal mold was determined as the difference between the 34Kh1M steel temperature recorded in the ingot's profit and its liquidus temperature. The temperature of the molds before pouring ranged from 30 to 110 ° C. The insulating mixture was not used during the casting process.

Casting was carried out at nine to nineteen ratios between ut and V.

The results of the experiments performed show that all the billets obtained from the ingots, cast by the method according to the invention, did not have surface defects, while the ingots obtained

in a known manner, had defects in the form of cracks.

The implementation of the invention allows to improve the surface properties as

where v

same billets made from ingots

hot deformation.

Claims (1)

Invention Formula The method of casting steel from above into metal molds, including preparing molds, overheating cast steel above the liquidus point, filling the mold and crystallizing the ingot, characterized in that, in order to improve the quality of the ingot surface, the filling of the mold is carried out at a rate equal to 26.7 - 29.0 v e, Filling rate and Depth, m / min; overheating of steel over the liquidus point in the mold, equal to 35-5 0e C.