SU738752A1 - Method of casting effervescent steel - Google Patents

Description

(54) METHOD OF SPILLING STEEL CASTING The invention relates to ferrous metallurgy, can be applied when casting boiling steel from above in one hundred leplavilny workshops. A method of intensifying the boiling of steel in molds is known, and it is proposed to use a mixture consisting of crushed limestone to a fraction of 0.1-5 mm of 20-40% 1 as an intensifier. The disadvantage of this method is that this increases the metal contamination by nonmetallic metals. inclusions. The known method of intensifying the boiling of steel when casting from the top at a speed of up to 1.8 m / min with the use of vibration of the bridge of the casting trolley and molds installed on it, including the vibration of all molds installed on the casting trolley. continuously from the beginning of the filling 2. The disadvantage of this method of intensification of boiling is the fact that at current casting speeds (3 m / min and more) such a vibration mode does not ensure a dense outer crust. At the same time, separate round bubbles remain in the lower and middle parts of the ingot,. which are located 3-8 mm from the surface. The generation of the latter: facilitated by vibration, which, due to fluctuations in external pressure, facilitates the formation of bubbles, but during high-speed casting at the initial moment of formation of a dense outer crust in the lower and middle parts of the ingot does not provide conditions for growth and floating of these bubbles, as the latter, as a result of the rapid increase in ferrostatic pressure and the relatively low segregation of carbon and oxygen at the crystallization front, grow slowly and are captured by crystals, whose growth in this period is ahead of bubble growth. The purpose of the invention is to provide a high quality ingot by increasing the thickness of its dense outer crust and the exclusion of the introduction of additional non-metallic inclusions. This goal is achieved by the fact that. vibroprocessing is performed after filling the mold at 70-80% of its height.

In this case, during the pause, a tight outer crust is formed in the lower and middle parts of the ingot.

With the filling of the tomb at 2/3 6S of the height of Likvatsi-carbon and oxygen on the crystallization in the lower and middle parts of the ingot, reaches values at which the processing begins | Cellular bubbles, the rate of 1fusionalization decreases, and the rate of gassing and growth of bubbles increases, at which time the vibration starts, which accelerates the scattering of growth and growth;

bubbles, provides conditions for THEIR emergence on the front of the Christianization - ..,., - ,,, -...,., -, ,,,, h ,,,, ",.,", .. ., - ,,, f, -J,: -, .-,. „,, -,,

-Example implementation method. Raschv1 and steel was carried out on the mark

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the growth rate of 3-5,5 m / min in ingots weighing 18-20 tons.

Yered casting steel on a steel pouring carriage between the molds was installed by an electromechanical vibrator; -which provided

vibration of the bridge steelworking T.

Tyoyezhi with ustyanovLennyy on it molds. During the casting, after the first mold was filled to 2/3 of its height, the vibration was continued and until the end of the crane moving with the ladle to the second one during the casting process, until the end of filling and during the casting.

73875Г

then they paused at the time of filling the second mold to 2/3 of its height. Thus, the cycle was repeated until all the molds on the casting cart were filled.

The use of the method of intensifying the boiling of steel when casting from above provides, as compared with the existing methods, an improvement in the quality of the ingot by increasing the thickness of the dense outer crust to 23-25 mm and. exclude additional non-metallic inclusions.

Claims (2)

1. Authors certificate of the USSR 443720, cl. On 22 D 27/00, 1974. 2. Kravchenko V.F. et al. Improving the quality of the steel sheet ingot by vibration. Collection New in the theory and practice of production of open-hearth steel, M., 1961 (rototype).