JPS6229473Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention is used for processing molten metal such as desulfurization, desiliconization, dephosphorization, and temperature adjustment of hot metal or molten steel.
This invention relates to improvements in gas blowing pipes for molten metal processing that blow inert gas or various processing agents together with inert gas into molten metal. Conventionally used gas blowing pipe 1
As shown in FIG. 1A, a large number of studs 3 are welded and attached to the outer periphery of a metal tube 2, and a monolithic refractory layer 4 is formed by lining with monolithic refractory material. In the gas blowing pipe 1 having such a structure, the coefficient of thermal expansion of the metal tube 2 is larger than that of the monolithic refractory layer 4, and in particular, the elongation in the longitudinal direction of the metal tube 2 is significantly large, so that the expansion allowance is small. 5 can absorb the expansion of the metal tube 2 in the diametrical direction, but it does not help the expansion of the metal tube 2 in the longitudinal direction. For this reason,
While the gas blowing pipe 1 is immersed in molten metal and used, as shown in FIG. Numerous welded studs 3 are subjected to tensile stress, resulting in ring-shaped cracks 6. The ring-shaped crack 6 is formed in the amorphous refractory layer 4
Because it is composed of one layer, it can easily reach the metal tube 2,
Molten metal infiltrates through this ring-shaped crack 6,
The metal pipe 2 was damaged by melting and became unusable, shortening the life of the gas blowing pipe 1. It is an object of the present invention to provide a gas blowing pipe for molten metal processing which eliminates the drawbacks of the conventional example and extends its service life. Hereinafter, the present invention will be explained in detail based on FIGS. 2A and 2B and FIG. 3. As shown in Fig. 2A and Fig. 3, the metal tube 8
An expansion allowance 9 is provided on the outer peripheral surface of the permanent lining 10.
is supported by a receiving metal fitting 14 fixed by welding to the upper part of the outlet pipe 13 of the metal pipe 8, a studded band 11 is tightened at an appropriate pitch around the outer periphery of this permanent lining 10, and a castable refractory material is lined. A work lining 12 in which a studded band 11 is embedded is provided to form a gas blowing pipe 7 for processing molten metal. When the gas blowing pipe 7 of the present invention configured in this way is used by immersing it in high-temperature molten metal,
The metal tube 8, the permanent lining 10, and the work lining 12 expand according to their respective thermal expansion coefficients due to the heat of the molten metal, but an expansion allowance 9 is provided between the metal tube 8 and the permanent lining 10. The expansion of the metal tube 8 in the diametrical direction is absorbed by the expansion allowance 9 and does not affect the permanent lining 10 and the work lining 12. The expansion of the metal tube 8 in the length direction is caused by the metal tube 8 and the permanent lining 10.
There is no problem because the work linings 12 and 12 are not diametrically engaged and are free from each other. When the permanent lining 10 is made of refractory sleeve bricks, cracks may occur especially due to vibration during use, but the studded band 11 provides a restraining force and suppresses cracks. The band with studs 11 is a metal band with a thickness of 0.5 to 3 mm and a width of 10 to 50 mm, and the studs have 3 to 5 V studs attached by welding. The studded band 11 is thin and is fastened to the permanent lining 10 at appropriate intervals, and since the permanent lining 10 and the work lining 12 are made of almost the same fireproof material, the permanent lining 10 due to thermal expansion. The behavior of the work lining 12 is almost the same, and the studded band 11 does not have an adverse effect on the work lining 12 due to thermal expansion. As shown in Figure 2B (after using 5 charges), the work lining 12
Cracks 15 that occur on the outer circumferential surface due to a volume change due to single-sided heating reach the outer circumferential surface of the permanent lining 10, but the cracks 15 are difficult to induce in the permanent lining 10, and therefore molten metal does not penetrate up to the metal tube 8. There are few. Work lining 12 contains 2-6% metal fiber.
By adding it, cracking and peeling phenomena can also be suppressed. Examples of the present invention are shown below and compared with conventional gas blowing pipes. A steel pipe with an outer diameter of 60.5 mm, a wall thickness of 5.5 mm, and a length of 4.7 m.
Permanent lining thickness of medium alumina castable
Table 1 compares the invented product which is lined with 50 mm, work lining thickness 50 mm, and work lining outer diameter 260 mm, and the conventional product which is lined with a single layer of medium alumina castable to an outer diameter of 260 mm.

[Table] Note that the studded band 11 of the example is made by attaching four studs to a stainless steel independent hose band manufactured by Fuji Koatsu Flexible Hose Co., Ltd. by welding. The studded band 11 is fitted into the permanent lining 10, and the screw 17 of the fastening part 16 is turned to tighten the permanent lining 10. When desulfurization work was carried out by blowing calcium carbide together with nitrogen gas into hot metal using the inventive product and the conventional product, the conventional product became unusable after 10 to 20 channels/piece, but the inventive product could only last for a number of years. is 20~
Improved to 30ch/book. The loss of the steel pipe was 100% in the conventional product, including the loss due to melting and perforation.
The product of this invention did not cause any melting, and only 20% of the damage caused by perforation occurred. As described above, according to the present invention, the occurrence of cracks that reach the metal pipe is reduced, and the service life of the gas blowing pipe for processing molten metal can be greatly extended.

[Brief explanation of the drawing]

Figure 1A is a partial vertical cross-sectional view of a conventional gas blowing pipe, Figure 1B is a partial vertical cross-sectional view of the gas blowing pipe according to the present invention after using the 5 charges shown in Figure 1A, and Figure 2A is a partial vertical cross-sectional view of a conventional gas blowing pipe. FIG. 2B is a partial longitudinal sectional view of one embodiment after using the 5 charge shown in FIG. 2A, and FIG. In the figure, 7... Gas blowing pipe, 8... Metal pipe, 9... Expansion allowance, 10... Permanent lining,
11...Band with studs, 12...Work lining, 13...Blowout pipe, 14...Bracket, 1
5...Crack.

Claims (1)

[Scope of utility model registration request] An expansion allowance 9 is provided on the outer peripheral surface of the metal tube 8, and a permanent lining 10 is provided by lining the metal tube 8 with a refractory sleeve brick or a monolithic refractory material. 14, and a studded band 1 is attached at an appropriate pitch around the outer periphery of the permanent lining 10.
This gas blowing pipe for molten metal processing is provided with a work lining 12 in which a studded band 11 is embedded by lining the workpiece 1 with a monolithic refractory material.