JPS649378B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing skid buttons, and more particularly to a method for manufacturing skid buttons having a composite structure of ceramic and metal. [Prior Art] Recently, the application of ceramics to skid buttons for the purpose of holding steel materials to be heated on walking beams and fixed beams of continuous or batch heating furnaces is being rapidly considered. Compared to heat-resistant steel, ceramics (a) have low thermal conductivity, (b) have excellent heat resistance and creep resistance, (c) have excellent oxidation resistance, and (d) have excellent wear resistance. When applied to the skid button of a heating furnace, it has the following advantages: (e) quality improvement by preventing skid marks on the heated material; and (f) energy saving in heating furnace operation. The reason is shown below. Heat-resistant steel skid buttons have problems such as creep and oxidation falling off under the high-temperature oxidizing atmosphere inside the heating furnace, so they are forced to cool with water via a base beam to which the skid buttons are fixed. Therefore, the skid contact area of the heated material is locally cooled, and the temperature distribution of the heated material is not uniform, which may cause defects in the steel material in subsequent processes. Heat-resistant steel skid buttons also require cooling, which results in a significant amount of thermal energy being dissipated. Therefore, when a ceramic skid button is used as a substitute for a heat-resistant steel skid button, the quality is improved by reducing furnace operating energy and reducing skid marks on the steel material, which is highly effective. However, since ceramic is a brittle material, it has the disadvantage of being extremely vulnerable to mechanical shocks and unbalanced loads or tensile and shear stresses. Therefore, when applying ceramic to skid buttons,
Considering the operating conditions of walking beam heating furnaces, etc., there was a risk of damage that could lead to destruction, such as cracks and cracks, occurring under high load conditions, so there remained a technical problem in using ceramic for skid buttons. That is the reality. Therefore, in order to apply ceramic to skid buttons in this way and take advantage of the advantages of ceramic as described above, it is necessary to increase the toughness of the ceramic skid buttons. One way to increase the toughness of ceramics is to combine them with metals. Possible methods for combining ceramic and metal include: simply mechanically combining ceramic and metal; integrating by shrink fitting, press fitting, etc.; and joining using adhesive. [Problems to be solved by the invention] In any of the above cases, the problem of the difference in thermal expansion coefficient between ceramic and metal occurs, so peeling occurs not only in the high temperature range of 1000°C or higher but also at temperatures before that temperature. Otherwise, phenomena such as drop-off, ie, loss of adhesive force and holding force, make it impossible to obtain a completely satisfactory bonding strength between ceramic and metal. Furthermore, although the above-mentioned methods involve shrink fitting and press fitting, there are problems with shrink fitting such as cracking of the ceramic due to thermal shock, and with press fitting there are problems such as cracking and chipping of the ceramic due to press fitting stress. There is a problem in that it cannot be used at temperatures where the difference in thermal expansion between ceramic and metal due to rising temperature exceeds the shrink fit and press fit. In addition, in the method using adhesives described above, a method has been considered in which the adhesive itself that forms the interface between ceramic and metal is made of a material with a coefficient of thermal expansion between that of ceramic and metal, but this method is insufficient for use at high temperatures. Adhesives that can withstand these conditions have not yet been provided. [Means for Solving the Problems] The purpose of the present invention is to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a method for manufacturing a skid button which is extremely excellent in various properties such as abrasion resistance and also excellent in mechanical properties such as impact resistance. The inventors of the present invention have conducted extensive research in order to develop a method for joining ceramics and metals that does not have the above-mentioned drawbacks. Then, we focused on and investigated a high-temperature, high-pressure bonding method using HIP treatment, which is completely different from the above methods. It was discovered that the bonding properties were excellent even under the conditions inside a heating furnace, and the present invention was completed. In other words, at a high temperature that is higher than the operating temperature of the heating furnace where the skid button is used, and at that temperature, HIP is performed at a gas pressure that is higher than the descending pressure of the metal, or more precisely, at a gas pressure that causes the strain of the metal to be 7% or higher at the HIP processing temperature.
The idea was that if the ceramic and metal were bonded using a bonding process, the bonded body of the ceramic and metal would have a satisfactory bonding strength at least up to the treatment temperature, that is, under heating furnace operation. It was also discovered that a ceramic-metal bonded body subjected to HIP treatment at the set temperature and pressure retains its bonding strength even at high temperatures during heating furnace operation, and can be used as a skid button. However, when the interface between ceramic and metal bonded by the HIP method was observed using an electron microscope and line analysis was performed, no intermediate product or interdiffusion phase was observed;
It was confirmed that a complex phase was formed due to microcracks with a width of 5 μm. The present invention has been made based on such knowledge, and the first invention is a cylinder or a cylinder-like shape made of stainless steel or heat-resistant steel (hereinafter sometimes referred to as "made of metal"). A ceramic sintered body of one or more types of silicon nitride, zirconium oxide, aluminum oxide, sialon, and silicon carbide, which is a cylinder or a column similar to a cylinder, is charged inside the cylindrical body. body and ceramic sintered body
The gist of the present invention is a method for manufacturing skid buttons characterized by joining by HIP method. A second aspect of the invention is that in the first aspect, the ceramic sintered body has a structure in which two or more divided bodies having different characteristics are stacked in the column height direction. Also the third
In the invention, a ceramic sintered body is attached to the recess of a metal columnar body which is a cylinder or a columnar body similar to a cylinder and has a recess formed on one end surface, and the ceramic sintered body and the columnar body are connected to each other. The gist of the present invention is a method for manufacturing skid buttons, characterized in that they are joined by the HIP method. A fourth invention is the third invention, in which the metal columnar body is made of different materials in the column height direction. In a fifth invention, the columnar body is a cylinder or a columnar body similar to a cylinder, and a recess is formed on one end surface of the column, one end in the height direction of the column where the recess is formed is made of heat-resistant steel, and the other end is made of mild steel. The central portion is made of stainless steel and is joined to the ceramic sintered body in the same manner as in the third invention. In the present invention, the material of the cylindrical body or columnar body to be joined to the ceramic is mainly stainless steel or heat-resistant steel. In addition, when performing HIP processing,
A powder compact of stainless steel or heat-resistant steel may be used as the material for the cylindrical body or columnar body. Further, as the ceramic, silicon nitride, zirconium oxide, aluminum oxide, sialon, or silicon carbide may be used, and one of these types may be used alone, or two or more types may be used in combination. [Example] The present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of a skid button manufactured by a method of carrying out the first invention. Reference numeral 10 indicates a skid button body, which is attached to a cooling pipe 30 via a mounting washer 20. The skid button body 10 is composed of a cylindrical body 11 having a cylinder or a shape similar to a cylinder, and a ceramic sintered body 12 inserted into the cylindrical body 11 and having a shape similar to a cylinder or a cylinder. . The cylindrical body 11 and the ceramic sintered body 12 are joined by the HIP method. FIG. 2 is a sectional view of a skid button manufactured by a method of carrying out the second invention. In this embodiment, there are a plurality of ceramic sintered bodies 12 in the column height direction (vertical direction in the figure) (in the illustrated embodiment, three
The structure is divided into parts 12a to 12c, with the uppermost part 12a and the central part 1
2b is made of dense ceramic, and the lower part 12c is made of low elastic modulus ceramic. In the case where the ceramic sintered body 12 is divided vertically as in the embodiment shown in FIG. Effective against static loads or impact forces. FIG. 3 is a sectional view of a skid button manufactured by a method of carrying out the third invention. In this embodiment, the skid button body 10 has a cylinder or a shape similar to a cylinder, and has a metal columnar body 14 having a recess 13 formed in one end surface (the upper end surface in the figure), and is attached to the recess 13. It is made up of a ceramic sintered body 15. Thus, the ceramic sintered body 15 and the columnar body 14 are joined by the HIP method. The skid button manufactured according to the fourth invention is the skid button shown in FIG. 3 in which the material of the metal columnar body 14 is made different in the column height direction. FIG. 4 is a sectional view of a skid button manufactured by a method of carrying out the fifth invention. In this embodiment, the columnar body 14 is composed of a plurality of (three in the illustrated embodiment) portions 14a to 14c made of different materials in the column height direction (vertical direction in the figure). In the illustrated embodiment, the uppermost part 1
4a is heat-resistant steel, the central portion 14b is stainless steel, and the lower portion 14c is mild steel. (Note that the first
Identical parts are designated by the same reference numerals in the figures. ) In the embodiment shown in Figs. 3 and 4, in which ceramic is installed only on the upper part of the metal, the material to be heated is lateral to the skid button due to the direction of movement of the moving bed, which is an operating condition of a walking beam type heating furnace. Effective against directional static loads or impact forces. Further, the embodiment shown in FIG. 4 has the advantage that steel materials such as mild steel, which have a low elastic modulus and are inexpensive, can be effectively used. Hereinafter, specific experimental examples of the present invention will be explained. Example of the present invention A silicon nitride sintered body with a diameter of 50 mm and a height of 64 mm as a ceramic, an outer diameter of 64 mm and an inner diameter of 50 mm as a metal,
The first one is made of stainless steel with a height of 64 mm.
HIP the skid button body with the shape shown in the figure.
Bonding was carried out under the conditions of 1300°C and 1200Kg/cm ² . Note that this condition is such that a strain of 7% or more is imparted to the stainless steel. The ceramic skid button, whose main body is the ceramic-metal bond produced in this way, was used in a walking beam heating furnace at 1250°C. Comparative Example As a comparison of the above example, a shrink fit product (shrink fit temperature 600℃,
Shrink fit allowance: 50 μm), press-fit items (press fit allowance: 50 μm), and metal-only skid buttons were used in a walking beam heating furnace at 1250°C in the same manner as in the above example. When the heating furnaces according to the above-mentioned examples of the present invention and comparative examples were actually operated for a predetermined period of time, additional results shown in Table 1 were observed.

[Table] From Table 1, it is recognized that the products produced by the method of the present invention have extremely excellent impact resistance and abrasion resistance, and can be used stably for a long period of time. In addition, in the heating furnace employing the product according to the present invention, the amount of cooling water used was significantly smaller, and energy costs were significantly reduced. Also, the quality was high. [Effects of the Invention] As detailed above, the method for manufacturing skid buttons of the present invention combines ceramic and metal, and integrates them by joining them using the HIP method. Compared to conventional skid buttons, the skid buttons manufactured by this method are
It has excellent features such as low thermal conductivity, excellent heat resistance, excellent creep resistance, excellent oxidation resistance, and excellent wear resistance, and prevents skid marks on heated materials. This makes it possible to improve quality and save energy in heating furnace operation. Furthermore, the skid button manufactured according to the present invention is extremely strong against mechanical shock and can be used stably for a long period of time.

[Brief explanation of drawings]

Each of FIGS. 1 to 4 is a sectional view showing a skid button manufactured by one method of carrying out the present invention. 10... skid button body, 20... mounting washer, 30... cooling pipe.

Claims (1)

[Scope of Claims] 1. Silicon nitride, zirconium oxide, aluminum oxide, sialon, and silicon carbide in a cylinder or a columnar shape resembling a cylinder are contained inside a cylinder or a cylinder-like stainless steel or heat-resistant steel cylindrical body. 1. A method for manufacturing a skid button, which comprises charging one or more types of ceramic sintered bodies, and joining the cylindrical body and the ceramic sintered body by a HIP method. 2. One or two types of silicon nitride, zirconium oxide, aluminum oxide, sialon, and silicon carbide in a cylinder or a columnar shape resembling a cylinder are placed inside a cylinder or a cylinder-like stainless steel or heat-resistant steel cylindrical body. The above ceramic sintered body having a structure in which two or more divided bodies with different properties are stacked in the column height direction is charged, and the cylindrical body and the ceramic sintered body are A method for manufacturing skid buttons, characterized in that they are joined by the HIP method. 3. Claim 2, wherein one of the divided bodies at one end in the column height direction is dense, and the other end has a lower modulus of elasticity than the one at the one end. The method for manufacturing skid buttons described in . 4. One type of silicon nitride, zirconium oxide, aluminum oxide, sialon, or silicon carbide is added to the recess of a columnar body made of stainless steel or heat-resistant steel that is a cylinder or a columnar body similar to a cylinder and has a recess formed on one end surface. Or, a method for manufacturing a skid button, characterized in that two or more types of ceramic sintered bodies are attached, and the columnar bodies and the ceramic sintered bodies are joined by a HIP method. 5. A columnar body made of stainless steel or heat-resistant steel that is a cylinder or a columnar body similar to a cylinder and has a recess formed on one end surface, and the material of the metal columnar body differs in the column height direction. A ceramic sintered body of one or more types of silicon nitride, zirconium oxide, aluminum oxide, sialon, and silicon carbide is attached, and the columnar body and the ceramic sintered body are attached.
A method for manufacturing skid buttons characterized by joining by HIP method. 6 A columnar body that is a cylinder or a columnar body that approximates a cylinder and has a recess formed on one end surface, where one end in the height direction of the column where the recess is formed is made of heat-resistant steel, the other end is made of mild steel, and the central part is made of heat-resistant steel. Silicon nitride, zirconium oxide,
1 of aluminum oxide, sialon and silicon carbide
1. A method for producing a skid button, comprising: attaching a seed or two or more types of ceramic sintered bodies, and joining the columnar body and the ceramic sintered body by a HIP method.