JP2010000519A - Method of inserting internal glass in hot extruded steel pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insertion method for uniformly forming internal glass of a hot extruded steel pipe. <P>SOLUTION: In a method for inserting the internal glass into the hot extruded steel pipe, rotation is imparted to a billet after the internal glass is inserted into the inside of the billet and also, by stipulating rotation holding time after inserting the glass, the glass of the inside of the billet is made into a molten state which is optimum to the extrusion and a glass film which is uniform in the circumferential direction is formed. Further, in the method of inserting the internal glass in the hot extruded steel pipe, the time is set by the size of the billet as the stipulation of the holding time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insertion method for uniformly forming an inner glass surface in a hot extruded steel pipe.

  In general, as shown in FIG. 1, the hot extrusion pipe manufacturing method is such that a die holder 3 is attached to one end of a holder having a container liner 2 in a liner holder 1, and a packing ring 4 and a die 5 are placed in the die holder 3. The hollow billet 6 as the material to be extruded heated from the other end to a predetermined extrusion temperature is inserted, and this is extruded through the pressing disk 7 by the hollow stem 8 with the mandrel adapter 9 installed therein, and the die 5 The billet 6 is extruded into a predetermined shape through the bolster liner 10 to obtain an extruded material. Reference numeral 11 denotes a mandrel.

  When manufacturing a steel pipe by hot extrusion as described above, the inner glass 12 for lubricating the tool is inserted into the inner surface of the billet which is a material to be extruded. That is, as the put glass 13 interposed between the end face of the die 5 on the container liner 2 side and the end face of the hollow billet 6, glass powder or glass powder and glass fiber are formed into a ring shape using a binder such as water glass. The put glass 13 is used, and the put glass 13 is gradually melted during the extrusion process and flows into the holes of the die 5 to lubricate the work material and the die 5.

  Further, the lubrication between the work material, the mandrel 11 and the container liner 2 assumes a molten film of glass powder applied to the inner and outer surfaces of the heated hollow billet 6 before the container liner 2 is charged. That is, a molten film of glass powder applied by rolling on a table covered with glass powder is applied to the outer surface of the hollow billet 6, and a glass powder charged with a spoon is applied to the inner surface of the hollow billet. Each of the molten films is responsible.

However, in the past, there was no provision for rotation holding time and there was excess or shortage of melting of the glass, part of the lubricating glass film in the processed part was extremely thin during processing, and seizure flaws occurred at this part, The actual condition is that the outer surface of the mandrel 11 is worn and damaged to cause deterioration of the inner diameter of the extruded tube, thereby shortening the mandrel life. As one of the improvements for that purpose, for example, as disclosed in Japanese Patent Application Laid-Open No. 10-263682 (Patent Document 1), in the processing method of the size dumblet for removing the surface flaws of the hollow billet used for hot extrusion, There has been proposed a method of processing a size dumblet that leaves the outer periphery of both end portions where the influence of surface wrinkles is less likely to occur on the product, and removes only the central portion.
JP-A-10-263683

  Patent Document 1 mentioned above is a processing method of a size dumblet that removes surface flaws of a hollow billet used for hot extrusion, and is a countermeasure after surface flaws are generated on a product. It is not a measure to prevent.

  As a result of diligent development to solve the problems as described above, the inventors managed a billet rotation method after insertion of the inner surface glass and a time after the insertion, thereby forming a uniform glass film on the inner surface of the billet. An object of the present invention is to provide a method for inserting an inner glass surface of a hot-extruded steel pipe that is formed and prevents wrinkling of a mandrel, which is a tool that comes into contact with the inner surface of a billet.

The gist of the invention is that
(1) In the method of inserting the inner glass into the hot-extruded steel pipe, the inner glass is inserted into the billet inner surface and then the billet is rotated. A method for inserting glass on the inner surface of a hot-extruded steel pipe, characterized in that the glass is made into a molten state optimum for extrusion and a uniform glass film is formed in the billet circumferential direction.
(2) The method for inserting an inner glass surface of a hot-extruded steel pipe is characterized in that the time is set for each billet size as the prescription for the rotation holding time described in (1) above.

  As described above, by controlling the billet rotation method after inserting glass into the billet inner surface and the time after insertion according to the present invention, a uniform glass film is formed on the billet inner surface, and the tool is in contact with the billet inner surface. The present invention has an extremely excellent effect that it is possible to improve the life by preventing the occurrence of surface flaws on a certain mandrel, reduce the manufacturing cost, and improve the quality of the inner surface of the extruded steel pipe.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 2 is a process diagram for inserting the inner glass according to the present invention. FIG. 2 (a) shows a state where the extrusion billet 15 is taken out from the conveyance line from the previous step and placed on the rotating roller 16 from the billet conveyance line 14. FIG. 2B shows a state in which the inner glass 12 on the inner surface of the extrusion billet 15 is inserted using a glass supply spoon while being placed on the rotating roller 16. FIG. 2 (c) shows a state in which the inner glass 12 on the inner surface of the billet 15 for extrusion is inserted and rotates for a specified time 18 to form a uniform glass film 17 in the circumferential direction to form an optimum molten state for extrusion. .

  After the specified rotation holding time of the extrusion billet 15 has elapsed, the extrusion billet 15 is taken out from the rotating roller 16 with a kicker, and the outer glass and inner glass are applied or attached, and extruded with a press using a predetermined die and mandrel. I do. In this case, the time is set for each billet size so that the glass can be extruded when it is in an optimum molten state.

  FIG. 3 is a view showing a method of inserting glass powder into the billet inner surface according to the present invention. As shown in this figure, after inserting a spoon 19 filled with glass whose upper surface has an opening in the extrusion billet 15, the spoon 19 is turned upside down to drop the glass powder 20 on the inner surface of the extrusion billet 15. . Thereafter, after the glass powder 20 drops on the inner surface of the billet 15 for extrusion, the spoon 19 is retracted. In this way, the glass powder 20 is inserted into the billet 15 for extrusion by the forward and backward operations of the spoon 19.

Hereinafter, the present invention will be specifically described with reference to examples.
As shown in FIG. 2, the extrusion billet 15 taken out from the conveyance line is placed on the inner surface of the extrusion billet 15 using a glass supply spoon in a state of being placed on the rotating roller 16 from the billet conveyance line 14. In a state where the inner glass 12 on the inner surface of the extrusion billet 15 is inserted, the rotation 18 is performed for a specified time. Table 1 shows the billet rotation holding time after glass insertion in this case. Note that the number of seconds of each size is displayed when the billet outer diameter 149 is set to the time a seconds at the time of implementation.

表１に示すように、ビレット外径１４９を基準として、小さい径のビレットは回転保持時間を短く、大きい径のものは回転保持時間を長く調整した。

As shown in Table 1, on the basis of the billet outer diameter 149, the rotation holding time was adjusted to be shorter for the billet having the smaller diameter, and the rotation holding time was adjusted to be longer for the larger diameter.

  As shown in Table 1 above, the billet is taken out after being rotated based on the control of the rotation holding time set for each billet size so that it can be extruded when the glass as the lubricant is in an optimal molten state. After applying or attaching the outer glass and the inner glass, the outer surface tool (die) and the inner surface tool (mandrel) were used to extrude with a press machine. As a result, it becomes possible to form a uniform glass film in the circumferential direction of the billet, prevent scratches on the mandrel, which is a tool that contacts the billet inner surface, improve the life of the extrusion tool, and manufacturing costs And improved the quality of the inner surface of the extruded steel pipe.

  Evaluation of scratches on the mandrel surface after use is performed by shot blasting to remove scale and glass on the mandrel surface after use, and then visually inspecting the surface for scratches. Moreover, although the rotational speed of the outer surface of the billet applied to the present invention is 260 mm / s in the embodiment, the range in which the present invention can be applied is 100 to 500 mm / s.

It is a figure which shows the extrusion method and die | dye of the steel pipe by a hot extrusion method. It is process drawing which inserts the inner surface glass which concerns on this invention. It is a figure which shows the method of inserting glass powder into the billet inner surface which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liner holder 2 Container liner 3 Die holder 4 Packing ring 5 Dies 6 Hollow billet 7 Pressing disk 8 Hollow stem 9 Mandrel adapter 10 Bolster liner 11 Mandrel 12 Inner surface glass 13 Pat glass 14 Billet conveyance line 15 Extrusion billet 16 Rotating roller 17 Glass film 18 Rotation for specified time 19 Spoon 20 Glass powder


Patent Applicant Sanyo Special Steel Co., Ltd.
Attorney: Attorney Shiina

Claims (2)

In the method of inserting inner glass into a hot-extruded steel pipe, the inner glass is inserted into the billet inner surface and then the billet is rotated, and the rotation holding time after glass insertion is specified, making it ideal for extruding the billet inner glass. A method for inserting glass on the inner surface of a hot-extruded steel pipe, characterized in that the molten glass is formed in a molten state and a uniform glass film is formed in the billet circumferential direction. The method for inserting an inner surface glass of a hot-extruded steel pipe, characterized in that the time is set for each billet size as the regulation of the rotation holding time according to claim 1.

Images