JPH04270007A - Front face lubricating disk for hot extrusion tube manufacture and hot extrusion tube manufacture - Google Patents

Abstract

PURPOSE:To prevent the scratch mark, the elephant skin and the spearhead from occurring on the extrusion tube by improving the front face lubrication on the time of hot extrusion. CONSTITUTION:On the hot extrusion tube manufacture that the billet 8 is inserted in the container 6, and the billet 8 is extruded from the die 2 provided at one end opening part of the container 6 and manufactured to the tube, the front face lubricating disk 10 for the hot extrusion tube manufacture composed of the machined sheet, the textile or the laminated material being the glass fiber as the main material is interposed between the die 2 and the billet 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front lubrication disk for hot extrusion pipe manufacturing and a hot extrusion pipe manufacturing method using the same.

0002

2. Description of the Related Art FIG. 9 is a vertical cross-sectional view showing a conventional hot extrusion pipe-making process, and 6 in the figure is a container. A die holder 4 is provided at one end opening of the container 6, and a donut-shaped die backer 5 is fitted into the inner edge of the die holder 4.
A die 2 is inserted adjacent to the die. A billet 8 having a hole in the center is inserted into the container 6 with its tip facing the die 2, and a mandrel 3 is inserted into the axis of the billet 8. A donut-shaped dummy block 7 is attached to the other end of the billet 8. A glass disk 1 having an inner diameter slightly larger than the inner diameter of the die 2 and a maximum outer diameter substantially equal to the inner diameter of the container 6 is attached to the billet 8 side of the die 2. The glass disk 1 is obtained by molding granular glass into a disk shape with a binder such as water glass, solidifying it, and drying it.

When the dummy block 7 is pressed in the direction of the arrow by a stem (not shown), the billet 8 is upset and pushed out from the die 2.
A tube is produced having an outer diameter corresponding to the inner diameter of the mandrel 3 and an inner diameter corresponding to the outer diameter of the mandrel 3. At this time, the glass disk 1 acts as a lubricant between the die 2 and the billet 8.

0004

[Problems to be Solved by the Invention] "Striations" occur on the outer surface of the tip of the tube extruded by the above-mentioned hot extrusion tube manufacturing method. This is caused by the unmelted material of the glass disk 1 adhering to the tip of the billet 8 during upsetting and scratching the outer surface of the billet during extrusion.

[0005] Also, in the initial stage of extrusion, the tip of the tube is not extruded evenly in the circumferential direction, resulting in a spear-like tip.
This creates a problem called a "spill tip," and the part with this "spear tip" has to be cut off, resulting in a poor product yield. At the "spear tip", the glass disk 1 comes into contact with the end surface of the billet 8 for a long time during upsetting, so the water glass that makes up the glass disk 1 softens first, and as a result, the granular glass softens continuously. Since this softened glass does not exert a uniform lubricating effect in the circumferential direction, it is thought that part of the billet 8 in the circumferential direction is extruded in advance.

Furthermore, crescent-shaped irregularities called "elephant skin" occur on the outer surface of the extruded tube in the circumferential direction over a range of about 2 m from the tip. However, it requires maintenance using a grinder or the like, which increases the cost, and the parts where this occurs have to be discarded, resulting in a problem of poor product yield. When the present inventors investigated the cause of "elephant skin", they found that
It was found that excessive melting of the glass disk 1 was the main cause. Details will be explained below. Since the billet 8 is rapidly squeezed inward at the opening of the container 6, the surface is sheared and wrinkled. On the other hand, since the glass disk 1 comes into contact with the end surface of the billet 8 for a long period of time, it softens to a large extent and flows into the creases described above. When the amount of glass disk 1 is small and the amount of softened water glass is small, the amount of glass brought into the inner surface of die 2 is also small, so the wrinkles are smoothed out by die 2, but the glass is softened and brought into the inner surface of die 2. If the amount is large, the wrinkles cannot be smoothed out by the die 2 and the tube is extruded, resulting in "elephant skin".

[0007] To prevent "streaks", a frontal lubrication disc must be used that does not produce unmelted solids during upsetting. In addition, in order to prevent "elephant skin" and "spear tip", it is possible to reduce the amount of water glass in the glass disk 1, but reducing the amount of water glass will reduce the strength of the glass disk 1. If the amount of glass disk 1 itself is reduced, there is a problem that lubrication will run out in the latter half of extrusion.

[0008] As a method for improving lubrication at the initial stage of extrusion,
In addition to glass disk 1, its outer diameter is glass disk 1
JP-A-59-179214 discloses a method of providing an auxiliary lubricant made of glass wool larger than the inner diameter of the billet between the glass disk 1 and the billet 8. However, since glass wool has a low density and a small amount of glass, it only has the effect of lubricating a few millimeters of the tip of the extruded tube, and has no effect of preventing the softened glass from flowing.

The present invention was made in view of the above circumstances, and by using a front lubrication disk for hot extruded pipes made of glass fiber paper, woven fabric, or stacked material,
The purpose of the present invention is to realize hot extrusion pipes that do not produce "stretch marks,""elephantskin," and "spear tips."

0010

[Means for Solving the Problems] A front lubricating disk for hot extrusion pipe manufacturing according to the first aspect of the invention is characterized in that it is constructed from a glass fiber paper, fabric, or stack without using water glass. Among glass fibers, glass wool has a low density as described above, so it has a low lubricating effect, and when used in combination with a conventional glass disk, it has a low effect on preventing the flow of softened glass, so it is excluded. A second invention provides a hot extrusion pipe manufacturing method in which a billet is inserted into a container and extruded from a die provided at one end opening of the container to form a pipe, in which a glass fiber paper product, woven fabric or stacked product is used. A front lubricating disk for hot extrusion pipe making comprising: is interposed between the die and the end face of the billet for pipe production.

[0011]

[Function] The front lubricating disk for hot extrusion pipe manufacturing of the present invention does not contain water glass, and the air contained inside has a heat insulating effect, so even if it comes into contact with the end face of the billet for a long time, it does not contain water glass. It does not soften a large amount at the beginning of extrusion as in the case of discs, but it softens gradually. Since the amount of glass melted at the beginning of extrusion is small, the occurrence of "elephant skin" and "spear tip" is suppressed. Furthermore, since no unmelted solid matter is produced during upsetting, the occurrence of "streaks" is also suppressed.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to drawings showing embodiments thereof. FIG. 1 is a vertical cross-sectional view showing the implementation state of the hot extrusion pipe manufacturing according to the present invention, and 6 in the figure is a container. A die holder 4 is provided at one end opening of the container 6, a doughnut-shaped die backer 5 is fitted into the inner edge of the die holder 4, and a die 2 is fitted into the container 6 side adjacent to the die backer 5. has been done. A billet 8 having a hole in the center is inserted into the container 6 with its tip facing the die 2, and a mandrel 3 is inserted into the axis of the billet 8. A donut-shaped dummy block 7 is attached to the other end of the billet 8. On the billet 8 side of the die 2, there is a front lubricating disk for hot extrusion pipe manufacturing according to the present invention (hereinafter referred to as an auxiliary disk).
10 and the glass disk 1 are sequentially attached.

The auxiliary disk 10 is made of glass fiber,
Consisting of fabric or stacks. The paper products constituting the auxiliary disk 10 include glass paper made from glass fibers, and the stacked material is made by stacking cut glass fibers and forming them into a mat shape using a binder. There are glass chopped strand mats, etc. An appropriate amount of glass powder and/or glass flakes may be mixed into the paper product, fabric, or stack. Note that the paper-making liquid used for paper products such as glass paper and the binder used for stacked products such as glass chopped strand mats are synthetic resin-based, and the auxiliary glass 10 does not contain water glass as a component. Inner diameter Dp of auxiliary glass 10
should satisfy the following equation (1). Da ≦Dp ≦Da +30
...(1) However, Da
Diameter at the starting point of the approach section of the die 2 This means that if Dp is smaller than Da, the inner edge of the auxiliary disk 10 will enter the approach section of the die 2 when upsetting the billet 8, and this entered portion will not be softened, so it will not be extruded. There is a risk of damaging the outer surface of the pipe, and Dp is Da.
This is because if it is larger than +30, the softened portion that comes into contact with the billet 8 during upsetting may not flow to the approach portion of the die 2, which may result in poor lubricity at the initial stage of extrusion.

The glass disk 1 is conventionally used and is obtained by molding granular glass into a circular shape using a binder such as water glass, solidifying it, and drying it. Its outer diameter is slightly smaller than the inner diameter of the container 6, and the inner diameter is the auxiliary disk 1.
30 mm or more larger than the inner diameter Dp of 0. this is,
This is to prevent the water glass component softened by the glass disk 1 coming into contact with the billet 8 during upsetting to be blocked by the auxiliary disk 10 and not to flow to the approach portion of the die 2. The thickness of the auxiliary disk 10 is set so as to ensure initial lubrication during extrusion, and the glass disk 1
The thickness should be sufficient to ensure lubrication until the end of extrusion.

In the hot extrusion pipe making apparatus of the present invention constructed as described above, when the dummy block 7 is pressed in the direction of the arrow by the Tesmu (not shown), the billet 8 is pushed into the die 2.
A tube is produced having an outer diameter corresponding to the inner diameter of the die 2 and an inner diameter corresponding to the outer diameter of the mandrel 3. At this time, the glass disk 1 and the auxiliary disk 10
acts as a lubricant between the die 2 and the billet 8.

FIGS. 2 to 5 are longitudinal sectional views showing other embodiments of hot extrusion pipe manufacturing according to the present invention. The surface of the auxiliary disk 10 on the side of the die holder 4 and the die 2 shown in FIG. 1 is tapered along the contact surface with these, but in the device shown in FIG. There is. Since the auxiliary disk 10 has flexibility, it follows the surface on the side of the die holder 4 and the die 2 during upsetting. In addition, in FIG. 1, the auxiliary disk 10 is
, glass disk 1 is installed in this order,
In the device shown in FIG. 3, this order is reversed. In the apparatus shown in FIG. 4, the auxiliary disk 10 whose inner diameter satisfies Da ≦Dp ≦Da +30 and whose outer diameter is at least (Dp+30) is replaced with a glass disk 1 whose inner diameter substantially matches the outer diameter of the auxiliary disk 10. It has a structure in which it is fitted on the inner edge side. In the device shown in FIG. 5, the auxiliary disk 10 according to the invention is designed as a lubricating disk. Although not shown, auxiliary disks 10 are provided on both sides of the glass disk 1.
You may also choose to have it installed. In addition, auxiliary disk 1
When paper glass is used as the material for 0, it will be laminated in multiple layers.

Examples of the present invention will be described below with reference to specific numerical values. The auxiliary disk 10 (outer diameter 175 mm, inner diameter 60 mm, thickness 15 mm) was constructed by stacking 30 sheets of glass paper (thickness 0.5 mm) made of E-glass fiber (outer diameter 9 μm), and this was used solely as a lubricating disk. , billet 8 made of SUS304 (outer diameter 174
mm, inner diameter 44 mm) was inserted into the container 6, and hot extrusion pipe production was performed. The heating temperature of billet 8 is 1220
℃, the extruded tube has an outer diameter of 45 mm, a thickness of 3 mm, and an extrusion ratio of 57.6. In parallel with this, a conventional glass disk 1 made of E glass (outer diameter 175 mm, inner diameter 6
0 mm, maximum thickness 35 mm) was used solely as a lubricating disk to manufacture pipes. FIG. 6 is a diagram showing the results of examining the extruded tube for "stripe flaws,""elephantskin," and "spear tip." From FIG. 6, it can be seen that according to the method of the present invention, the surface of the extruded pipe becomes smooth, and the occurrence of "stripe marks,""elephantskin," and "spear tips" is suppressed.

Next, as shown in FIG. 1, glass paper (thickness 0.5 mm) made of E glass fiber (outer diameter 9 μm)
) auxiliary disk 10 (outer diameter 175 mm)
, inner diameter 60 mm, thickness 15 mm) and a glass disk 1 made of E glass as well.
Billet 8 consisting of 304 (outer diameter 174 mm, inner diameter 4 m)
m) was inserted into the container 6 and hot extrusion pipe production was carried out. The heating temperature of the billet 8 is 1220° C., the dimensions of the extruded tube are 45 mm in outer diameter, 3 mm in thickness, and the extrusion ratio is 57.6. Figures 7 and 8 show the "streaks" on the extruded tube,
It is a figure showing the result of examining "elephant skin" and "spear tip." From FIGS. 7 and 8, when the inner diameter of the auxiliary disk 10 is larger than the inner diameter of the glass disk 1, "streaks", "elephant skin" and "
If the inner diameter of the glass disk 1 is larger than the inner diameter of the auxiliary disk 10, the occurrence of "streaks,""elephantskin," and "spear tips" will be suppressed, and if the difference in inner diameter is 30 mm rather than 10 mm. It can be seen that the suppressing effect is greater. It is also understood that the glass disk 1 and the auxiliary disk 10 may be attached in any order.

[0019]

As described above, in the present invention, since a front lubricating disk for hot extruded pipes made of glass fiber paper, woven fabric, or stacked material is used, it is possible to prevent "streaks,""elephantskin," and "spears." The present invention has excellent effects, such as being able to produce hot extrusion pipes that do not produce tips.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an implementation state of hot extrusion pipe manufacturing according to the present invention.

FIG. 2 is a longitudinal sectional view showing another implementation state of hot extrusion pipe manufacturing according to the present invention.

FIG. 3 is a longitudinal sectional view showing another implementation state of hot extrusion pipe manufacturing according to the present invention.

FIG. 4 is a longitudinal cross-sectional view showing another implementation state of hot extrusion pipe manufacturing according to the present invention.

FIG. 5 is a longitudinal sectional view showing another implementation state of hot extrusion pipe manufacturing according to the present invention.

FIG. 6 is a diagram showing the results of examining "stripe flaws,""elephantskin," and "spear tips" in tubes extruded by the method of the present invention and the conventional method.

FIG. 7 is a diagram showing the results of examining "stripe flaws,""elephantskin," and "spear tips" in tubes extruded by another method of the present invention and a conventional method.

FIG. 8 is a diagram showing the results of examining "stripe flaws,""elephantskin," and "spear tips" in tubes extruded by another method of the present invention and a conventional method.

FIG. 9 is a longitudinal cross-sectional view showing the state of implementation of conventional hot extrusion pipe manufacturing.

[Explanation of symbols]

1 Glass disk 2 Dice 3 Mandrel 4 Die holder 6 Container 8 Billet 10 Auxiliary disk

Claims (2)

[Claims] 1. A front lubrication disk for hot extrusion pipe making made of glass fiber paper, fabric or stack. 2. In a hot extrusion pipe manufacturing method in which a billet is inserted into a container and extruded from a die provided at one end opening of the container to form a pipe, a glass fiber paper product, a woven product, or a stacked product is used. 1. A hot extrusion pipe making method, characterized in that a front lubricating disk for hot extrusion pipe making made of a material is interposed between the die and the end face of the billet.