JPS6356469B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies the required temperature and pressure at the same time to achieve, for example, compression molding and sintering of metal powder, improving internal defects in precision casting products, improving internal defects in ceramic parts, or molding and sintering. The present invention relates to a cylinder constituting a heating furnace used in a hot isostatic pressing apparatus suitable for performing hot isostatic pressing.

Hot isostatic pressing equipment (hereinafter referred to as HIP equipment) has already been used to improve internal defects in cemented carbide tools and is gaining popularity, but in recent years new materials such as ceramics and cermets have been developed. There is a tendency for the scope of application to expand as a result.

The heating furnace, which is the main component of the HIP equipment, is sometimes housed in a pressure-resistant container, so it is required to be compact and high-performance. , molybdenum, tungsten, tantalum, etc. are used in the high temperature range. In addition, the heat insulating wall of a heating furnace for HIP equipment is generally a multilayer structure in which multiple cylinders with different diameters are installed concentrically, and the gaps between the installed cylinders are filled with glass fiber, carbon fiber, etc. ing.

The heating furnace for HIP equipment configured in this way is usually under pressure of an inert gas such as argon gas (~
2000Kg/cm ² ), the structure of the furnace requires different considerations than vacuum furnaces. In other words, in a vacuum furnace, heat transfer by convection can be ignored, and most of the heat transfer is by radiation, so a multilayer wall with the function of a thin plate is sufficient as an insulating wall structure, and each layer wall is oriented in the radial direction. Although it is not necessary to have a structure that does not allow gas to pass through, heating furnaces for HIP equipment must be operated surrounded by high-pressure gas, which has a density comparable to that of water and a viscosity significantly lower than that of water. Moreover, in order to ensure heat retention performance, the layered wall (generally cylindrical) that constitutes the insulation wall must suppress gas flow in the radial direction and divide the convection area inside the insulation wall.

For this reason, the cylinder that makes up the heat insulating wall must be thin, strong, and processed with high precision, and as a basic function, it must have a structure that does not allow gas to pass through in the radial direction. .

However, materials such as molybdenum, tungsten, and tantalum, which are used in high-temperature areas for heat insulating walls, are difficult to work with because they themselves are heat resistant, and cannot be freely welded. The reality is that they are struggling.

A conventional cylindrical insulating wall for a heating furnace is shown in FIG.
This cylinder 01 is made by bending a strip plate 02 of the required thickness to a predetermined diameter, and with both ends abutted, cover plates 03 and 04 are applied to the front and back sides, respectively, and the belt plate 02 is bent at a predetermined pitch along the axial direction of the cylinder. A pilot hole for the rivet is drilled, and then the rivet is fastened with rivet 05 and processed into the required shape. FIG. 2 shows the cross-sectional shape of the part fastened with the rivet 05.

The circumference 01 manufactured in this way is, as shown in FIG.
Gas naturally flows from the inside to the outside as shown by arrow A through the gap between the ends,
It does not satisfy the necessary functions as a cylinder for the insulation wall of a heating furnace for HIP equipment. Furthermore, the wall thickness of the cylinder depends on the thickness of the available strips, and it is difficult to manufacture a cylinder with any desired wall thickness.

In view of the above-mentioned problems with the conventional cylinders for insulation walls, the present invention aims to prevent gas flow from the inside of the cylinder to the outside and to make it possible to obtain the required wall thickness. It is characterized in that it is wound in multiple layers to form a cylinder with a predetermined wall thickness and diameter, and is secured by a fastening member that passes through the beginning and end of the winding of the band in the thickness direction.

Embodiments according to the present invention will be described below based on the drawings. FIG. 4 is an external view of the cylinder 1, FIGS. 5 and 6 are sectional views of various parts of FIG. 4, and FIG. 7 is an explanatory view of the processing method. In the figure, reference numeral 1 denotes a cylinder formed by winding a strip 2 in multiple layers, and a winding start section 4 and a winding end section 5 of the strip plate 2 are fastened together with a rivet 3. Next, a method of processing such a cylinder 1 will be explained. FIG. 7 shows a state in which the band plate 2 wound in multiple layers is inserted into two annular sizing bands 6 having predetermined inner diameter dimensions. At this time, at the time of multi-layer winding of the strip plate 2, the multi-layer winding cylinder is wound with a diameter smaller than the inner diameter of the sizing band 6, and is temporarily secured to prevent unwinding, and the sizing band 6 is multi-layer wound. If the temporary fixing of the multilayer-wound cylinder is removed after inserting it into the cylinder, the multilayer-wound cylinder will unwind in the sizing band 6, and will stop unwinding when it comes into close contact with the sizing band. At this time, the winding start part 4 and the winding end part 5 are formed into a cylindrical shape by being bent in advance. Winding start part 4 and winding end part 5
are made to overlap, and in the state shown in FIG. 7, pilot holes for a fastening jig are drilled at predetermined intervals in the cylindrical axis direction in the overlapped portion. A fastening jig is attached to this prepared hole, and the state in which processing is completed is shown in Figure 4.

In this embodiment, a rivet 3 is used as the fastening member, but a screw may also be used. FIG. 5 is a cross section of the V section in FIG.
FIG. 6 is a cross-sectional view of the portion shown in FIG. 4, and shows a state in which the overlapping portions are fastened with rivets 3.

As shown in the figure, the cylinder 1 has a structure in which a number of layers of strip plates 2 are stacked on top of each other in the radial direction, so that gas flow from the inside of the cylinder to the outside is difficult to occur.

FIG. 8 shows another embodiment according to the invention. This is a cylinder in which a band plate 2 is wound in two layers, and the winding start part 4 and the winding end part 5 do not overlap, and each part is fastened with a rivet 3. This cylinder is suitable for processing a cylinder by winding relatively thick strips in a small number of layers.
This is effective in cases where the overlapping portion becomes too thick when the band plate is fastened by overlapping the winding start portion and the winding end portion.

As explained above, since the cylinder of the present invention has a structure in which thin strips are wound in multiple layers, gas flow from the inside to the outside of the cylinder is difficult to occur, and the wall thickness of the cylinder is reduced unlike in the conventional case. Any strip can be made without being affected by the thickness of the strip.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional cylinder, FIG. 2 is a partial sectional view of FIG. 1, and FIG. 3 is a partial sectional view of FIG. 1. FIG. 4 is a perspective view showing one embodiment of the present invention, FIG. 5 is a partial sectional view of FIG. 4, FIG. 6 is a sectional view of FIG. 4, and FIG. 7 is a perspective view explaining the manufacturing method. be. FIG. 8 is a perspective view showing another embodiment of the present invention. 1...Cylinder, 2...Strip plate, 3...Rivet, 4
...The beginning of winding, 5...The end of winding.

Claims (1)

[Claims] 1. A vertical cylindrical furnace characterized in that a thin strip is wound in multiple layers to form a cylinder with a predetermined wall thickness and diameter, and the strip is secured with a fastening member that penetrates the beginning and end of the winding in the thickness direction. Insulated wall for cylinder.