Continuous casting anti-blocking submersed nozzle

An anti-clogging, immersion technology, used in foundry equipment, casting melt containers, metal processing equipment, etc., can solve the problems of drift vibration, affecting the outflow of molten steel, affecting the strength of the nozzle, reducing secondary oxidation, stable and continuous pouring effect

Active Publication Date: 2019-03-05

BAOSHAN IRON & STEEL CO LTD

7 Cites 3 Cited by

AI-Extracted Technical Summary

Problems solved by technology

In this process, the following problems are usually encountered: ① During the baking of the nozzle, due to the presence of graphite inside the nozzle, carbon oxidation will occur after baking, resulting in a decrease in the strength of the nozzle material; When the slag under the bottom is prone to fall off

②During use, due to the physical and chemical reaction between the slag line position of the nozzle and the mold slag inside the cryst...

Method used

On the nozzle body 2 side walls, a pair of argon blowing inlets 3 are symmetrically arranged, and the argon blowing inlets 3 are arranged on the nozzle slag line 4 tops near the nozzle slag line 4 places, which run thro...

Abstract

The invention provides a continuous casting anti-blocking submersed nozzle which comprises a nozzle body. An inner cavity of the nozzle body is cylindrical, and an inlet of the nozzle body is formed in the top of the nozzle body. A nozzle slag line is arranged in the middle of the nozzle body, and two discharging holes are symmetrically formed in the side wall, close to the bottom of the nozzle body, of the nozzle body. The discharging holes are inclined downwards from the inside to the outside of the nozzle body. The continuous casting anti-blocking submersed nozzle can be widely used for a continuous casting steel production procedure, secondary oxidation of molten steel is reduced, and stable and continuous casting is achieved. In order to improve the corrosion resistance of the slag line, corrosion-resistant BN is added to the slag line of the nozzle, and produced corrosion products cannot pollute the molten steel and cannot be caked. Argon is blown into the nozzle, and caking is avoided.

Application Domain

Melt-holding vessels

Technology Topic

SlagCorrosion resistant +4

Image

Examples

Experimental program(1)

Example Embodiment

[0022] Example 1

[0023] Such as figure 1 As shown, a continuous casting anti-clogging immersion nozzle includes a nozzle body 2. The inner cavity of the nozzle body 2 is a cylinder. The inlet of the nozzle body 2 is located at the top of the nozzle body 2, and is arranged in the middle of the nozzle body 2. There is a spout slag line 4, and two spout holes 5 are symmetrically provided on the side wall of the spout body 2 near the bottom of the spout body 2, and the spout holes 5 are inclined downward from the inside to the outer part of the spout body 2.

[0024] Outside the side wall of the nozzle body 2 between the top of the nozzle body 2 and the nozzle slag line 4, a thermal insulation cotton 1 is provided.

[0025] On the side wall of the nozzle body 2, a pair of argon blowing inlets 3 are symmetrically arranged. The argon blowing inlet 3 is arranged above the nozzle slag line 4 and close to the nozzle slag line 4, which penetrates the side wall of the nozzle body 2 and the insulation cotton 1, and can pass directly The argon blowing inlet 3 blows argon into the inner cavity of the nozzle body 2 to purge the inner wall and avoid internal nodules.

[0026] The angle between the discharge hole 5 and the axis of the nozzle body is 70°.

[0027] The raw material of the nozzle body is composed of 60wt% alumina, 35wt% graphite and 5wt% silicon carbide. The raw materials are mixed uniformly and sintered into the nozzle body after stamping and forming according to conventional methods in the art.

[0028] The nozzle slag line is an annular sleeve sheathed outside the nozzle body, and its raw material is composed of 70w% ZrO-CaO material and 30wt% BN; wherein, the ZrO-CaO material consists of 60wt% ZrO and 40wt% CaO composition. Both ZrO and CaO have a relatively high melting point, above 2250°. After the two are uniformly mixed, they are uniformly mixed with BN to form a nozzle slag line. The nozzle slag line and the nozzle body are press-formed under mechanical pressure together according to the conventional process method, and then heated and fired. The pressing pressure is 60 MPa, the pressing time is 30 minutes, the firing temperature is 900° C., and the firing time is 24 hours.

[0029] A layer of spit hole film is provided on the surface of the spit hole in contact with molten steel. The raw material of the spit hole film is composed of 60wt% magnesium and 40wt% magnesium aluminum alloy. The aluminum content of the magnesium aluminum alloy is 62wt%. The magnesium content is 38% by weight. The preparation method of the spit hole film is to grind magnesium aluminum alloy and magnesium into powder, mix them evenly according to the ratio, apply phenolic resin to the nozzle body at the position where the spit hole is opened, and bake at 1300°C for 2 hours to generate MgO and Al 2 O 3 Covers the surface of the nozzle body with discharge holes.

[0030] The material of the thermal insulation cotton is Al 2 O 3 -CaO-C composite fiber cotton, the specific raw material composition is 70wt% Al 2 O 3 , 25wt% CaO and 5wt% graphite. During preparation, the components are evenly mixed to form composite fiber cotton, which is wrapped outside the side wall of the nozzle body. The preparation method of the composite fiber cotton is prepared by referring to the conventional method in the prior art, that is, each raw material is drawn into silk at high temperature, and then the silk is knitted into a cloth on a knitting machine to obtain the composite fiber cotton.

[0031] The present invention can adopt the performance of the continuous casting anti-clogging immersion nozzle obtained by the XD technology (Exothermal dispersion process) test. The principle of the XD technology is to mix the elements participating in the reaction with the matrix, and the reactants are heated to the working temperature. To see the degree of reaction before and after the test (or improvement). The present invention mainly aims to reduce the clogging of the continuous casting nozzle, and mainly prevents the alumina (Al 2 O 3 ) Adhesion to the spout hole and inner cavity at the nozzle. Therefore, simulate the process of molten steel passing through the nozzle to test whether there is a direct reaction between alumina and the composition of the nozzle.

[0032] While testing the performance of the continuous casting anti-clogging immersion nozzle obtained in Example 1, the nozzles of Comparative Examples 1 to 2 were tested for comparison. The difference between the nozzle of Comparative Example 1 and the nozzle of Example 1 is that: Comparative Example 1 has no insulation cotton The difference between the nozzle of Comparative Example 2 and the nozzle of Example 1 is that: Comparative Example 1 does not spit out the porous film.

[0033] The specific test process is as follows: lay the nozzle horizontally, cut the nozzle longitudinally to prepare a semicircular section (300mm*300mm) with a hollow inside. Mix 5wt% alumina powder (200 mesh) and 95wt% pure iron powder (200 mesh) evenly (simulating molten steel) and place it in the nozzle, evenly spread the inner cavity of the nozzle. After experimenting at 1560°C for 5 hours, check The alumina reacts with the cavity of the nozzle and the position of the spit hole.

[0034] In the continuous casting anti-clogging immersion nozzle obtained in Example 1, the nozzle and the spit hole did not undergo any reaction, that is, the thickness of the reaction layer was basically zero.

[0035] In the nozzles of Comparative Examples 1 to 2, a reaction layer with a depth of 2 mm or more occurred, that is, alumina adhered to the inner cavity of the nozzle and the spit hole.

PUM

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