JPS5829562A - Manufacture of stave by insert casting of pipe - Google Patents

Abstract

PURPOSE:To decrease the abrasion of staves and to prevent the erosion of a pipe and the propagation of cracking in the body of the staves by forming unpacked parts between the outside surface of the pipe and an insert metal by means of metallic wires wound on the pipe. CONSTITUTION:After metallic wires 2 are wound and fixed in >=1 piles around a cooling pipe 1, the pipe is set in a mold, and cast steel 4 is cast in a suitable casting temp. range, whereby the pipe 1 is cast in said steel. Here, the molten metal cools down while melting the wires wound in tight contact with each other or spacially at a constant pitch on the outside surface of the pipe partially. Before arriving at the outside surface of the pipe, the molten metal solidifies, thus forming unpacked parts 3. The pipe and the insert metal are purposely held without contacting and therefore in the event of generation of any cracking in the insert metal, the cracking is prohibited from transmitting to the pipe. The decrease in cooling efficiency by such absence of contact is extremely slight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method suitable for casting a cooling pipe of a blast furnace stave, and its purpose is to reduce wear and tear on the stave and prevent melting of the cooling pipe. Furthermore, even if a thermal crack or the like occurs in the stave body, it is intended to prevent the crack from propagating to the cooling pipe, thereby improving the durability of the stave.

Generally, the life of a blast furnace using a stave is determined by the durability of the stave. However, the current stave cut material is cast iron, which has a low melting point and is brittle.
Melt damage and thermal cracks during use.

Significant wear and tear due to high temperature wear, etc. In other words, stave wear is caused by flake graphite in cast iron being 002 in the furnace gas.
, S02, 20, etc., plate-shaped defects are formed in the cast iron like an ant nest, making it brittle.
As a result, the materials inside the furnace cause wear and tear due to cracks, etc.

Therefore, in order to reduce the wear rate of the stave, heat-resistant cast steel without graphite is essential.

However, cast iron and cast steel have significantly different melting points; the former can be cast at around /300"O-/3!;0"C, while the latter can be cast at /! ;3; Disadvantages include the casting temperature of approximately 0"C and the need for a feeder to prevent cavities in the case of cast steel casting, which slows solidification of this part and causes melting of the cooling pipe. was there.

A technique proposed to solve this situation is disclosed in Japanese Patent Application Laid-Open No. 33-1972/Revised No. 2t1. In other words, Tokukai Akira! ;!
- / No. 63.26g places a rod wire on the outside of the pipe at a predetermined distance from the pipe, pours molten metal into the outside of the pipe, and controls the temperature of the molten metal by the 1 m long wire to prevent the pipe from melting and damage. It is a pipe casting technology that involves reducing the fluidity of the molten metal to such an extent that no unfilled portions occur, and the pipe casting is in contact with or welded to the metal that is being cast. However, in the technology of JP-A Showa S-/Otsu S no Otsu Ni, unless the melting point of the pipe is significantly lower than that of the metal in which it is cast,
It is almost impossible for the pipe and the metal to be in uniform contact without welding, and if the melting point of the pipe is close to the melting point of the metal to be cast, or the melting point of the metal to be cast is higher. In this case, a mixture of contact and welding, or a situation where welding occurs, is unavoidable. In areas where the pipe and cast metal are welded together, if a crack occurs in the cast metal during use, it will not be possible to prevent the crack from propagating to the pipe, and
1. There is a risk of causing a water leakage accident.

The present invention solves two series of problems and drawbacks, and at the same time
This was done in order to prevent the propagation of cracks to cooling pipes and prevent water leakage accidents even in the event that thermal cracks occur. In the method for manufacturing the Gurumu stave, after fixing the metal wire on the surface of the cooling pipe by wrapping it seven times or more, there is an unfilled part between the outer surface of the cooling pipe and the weld metal after cooling and solidification. Cooling to occur
A method of manufacturing a stave by casting a pipe, characterized by casting a stave with molten metal.

The present invention will be explained in detail below.

Figures (a) and (bl) show stave models produced by the manufacturing method of the present invention, and (1) is an enlarged view of part A in (a). In the figure, / is a cooling pipe, 2 is a metal wire, 3 is a portion not filled with molten metal, and g is a cast steel. .

The manufacturing method is to first wrap metal wire around the pipe seven times. In this case, the wire does not necessarily have to be wound seven times; for example, a thinner diameter wire may be wound twice or more, or a wire having a non-circular cross section may be wound.

Next, the cooling pipe material is set in a mold (not shown), and the cast steel is cast into the pipe at an appropriate casting temperature. At this time, the temperature of the molten metal decreases while partially melting the wire wound in close contact with the outer surface of the cooling pipe with a fixed pinch or at a distance, and solidifies before reaching the outer surface of the pipe, forming an unfilled portion 3.

The unfilled portion 3 is formed appropriately by selecting the wire cross section, pitch, number of layers, etc. depending on the casting temperature.

In the present invention, the reason why the pipe and the cast metal are kept in a non-contact state is that, as seen in the explanation of the prior art described above, the pipe and the cast metal are in a molten state. This is to prevent the crack from propagating to the pipe if a crack were to occur in the cast metal during use. Furthermore, speaking about cooling efficiency, although the pipe and the cast metal are not in contact, the pipe and wire touch the metal and the wire is welded to the cast metal, so the drop in cooling efficiency is extremely slight. .

Next, the effects of the present invention will be described in more detail with reference to Examples.

Example component composition 0:0. /2%, Si: (1), 54%, M
n: 060%.

p: 0.0.25%, S: o, ois%,
Ni: 0. 'l! r%, Or: /3. ! ;
A 3.3 mm thick mild steel wire was tightly wrapped twice around a cooling pipe material with a wall thickness of 4 mm and fixed.

Next, this cooling pipe was set in a mold (not shown), and the component composition was 0:0.3%, Si: 7.
．． 1%, Mn:OI2%, P: 0.
020%, S: 0.0%, Ni: 0
．． 1-3%, Or:/3. A cast pipe was cast with l='% cast steel in the temperature range of 25 to 11°C.

In the stave model manufactured in the above manner, the cooling pipe did not suffer from melting at all. For comparison, a casting pipe with the same shape as the same model and completely integrated with the casting body was inserted into a furnace at approximately 930°C, and water at a temperature of B''C was flowed into the cooling pipe to cool it. When the efficiency was measured, even though the stave model using the present invention had an unfilled portion between the cooling pipe and the stave body, the difference in cooling efficiency between the two was so small that it was barely noticeable.

Furthermore, a high-temperature fatigue test piece was taken to include the main body of the cooling vibe stave, and a high-temperature fatigue test was conducted with a notch on the stave side in the temperature range of 00 to 100''C. Test piece 6" taken from the stave base material has a fatigue strength of about /3~. ! It was found that not only did the stress increase by a factor of j, but also that at low stress it took a significantly longer time for cracks in the stave body to propagate to the cooling pipe.

As described above, the use of cast steel, which is extremely advantageous in preventing cracks and wear in the stave body, not only reduces the wear rate of the stave [IJ] but also prevents cracks from forming in the cooling pipe. Since there is no metal bond between the stave base materials, cracks will not propagate to the cooling pipe, making it extremely effective in preventing water leakage accidents and, in turn, having an excellent effect on extending the life of the blast furnace. be.

[Brief explanation of the drawing]

Drawing (a) is a partial view of the station in which the cooling pipe is cast with cast steel. /... Cooling pipe, 2... Metal wire, 3... Molten metal unfilled portion, G... Stave base material (cast steel). Patent applicant: Nippon Steel Corporation Continuation of page 1 ■Inventor: Kazube Fujisawa 146-59 Bold, Tobata-ku, Kitakyushu City, Nippon Steel Corporation, Construction Division 0 Inventor: Hiroto Arata, Bold: Tobata-ku, Kitakyushu City Nakahara 46-59 Nippon Steel Corporation Internal Procedures Amendment 1 (Method) 1982/p February 411, Title of invention Method for manufacturing staves by pipe casting 3 Relation to the case of the person making the amendment Patent application Person 4 Agent 〒1.03 Address 24] -04415 Daily edition of amendment order January 26, 1981 (shipment date) 6 Column for brief explanation of drawings of specification subject to amendment, drawings, power of attorney 7 Amendment Contents of the amendment as per the attached sheet 1, Description 4 In the brief explanation of the drawings, the last line of page 7 to the first line of page 8 reads, ``Figure 1 is a diagram of the internal structure of a staple model in which cooling pipes are cast in cast steel. , Figure 2 shows part A in Figure 1.'' 2 Correct the drawing as shown in the attached sheet. 3 Amend the power of attorney as shown in the attached sheet. Figure 1 'jf> Figure 2

Claims (1)

[Claims] In a method for manufacturing a stage in which a cooling pipe is cast with molten metal, after fixing the cooling pipe by wrapping a metal wire seven times or more around the surface of the cooling pipe, the outer surface of the vaginal cooling pipe and the welded metal after cooling and solidification are bonded. A method of manufacturing a stave by casting a cooling pipe, the method comprising casting a cooling pipe with molten metal so that an unfilled portion is created between the cooling pipes.