Extrusion needle and extrusion method for large-specification thin-walled pipe or hollow profile

Abstract

The invention discloses an extrusion needle and an extrusion method for a large-specification thin-walled pipe or a hollow profile. The extrusion needle comprises a perforation sizing section and an expansion section. The extrusion needle is characterized in that the diameter of the perforation sizing section is less than that of the expansion section; and a transition section is arranged outside the perforation sizing section; the extrusion method comprises the steps of hole drilling and boring, hole expanding and extrusion forming, in particular comprises the following steps of hole drilling and boring, hole expanding, blank heating, extrusion needle perforation sizing and automatic hole expanding, wherein the extrusion forming is finished through an extrusion action; and the needed thin-walled pipe or the hollow profile is obtained. Through adjusting the structure of the extrusion needle, the method shortens the extrusion procedure of the thin-walled pipe or the hollow profile; and the extrusion needle finishes two action processes of hole expanding and sizing, so that the production range of an extruder is widened, the loss of hole drilling / boring metals and drillers is reduced, the number of drilling / boring machine equipment is decreased, the equipment power is reduced, the tonnage of a hole expander is reduced, the hole expanding travel is shortened, the production cost is reduced, the production efficiency is improved, and the energy consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of metal thermal processing, and further belongs to the technical field of metal extrusion, in particular to an extrusion needle and an extrusion method for large-scale thin-walled pipes or hollow profiles. Background technique [0002] When hot-extruding some large-scale thin-walled pipes or hollow profiles, it is generally necessary to expand larger holes. If it is produced with a larger-sized extrusion barrel, it will be easier to expand the hole, but the extrusion force will be very large, which often exceeds the capacity of the equipment; if it is produced with a smaller-sized extrusion barrel, it will be more difficult to expand the hole. In the prior art, this kind of problem is generally solved by reaming the hole twice, that is, reaming the hole on the reaming machine twice. For example, on a 50MN steel extrusion machine, use a Ф400mm extrusion barrel to extrude a Ф273mm×10mm 304 stainless steel tu...

AI Technical Summary

Problems solved by technology

For example, on a 50MN steel extrusion machine, use a Ф400mm extrusion barrel to extrude a Ф273mm×10mm 304 stainless steel tube, and the outer diameter of the billet is 383mm. If the hole is reamed in place at one time, even if the Ф160mm hole is drilled, the expansion coefficient of the hole is as high as 1.53. The hole reaming process is not easy, the reaming force will be very large, and even if the hole can be reamed, the upper end surface is inclined seriously, and the inner surface is prone to defects, and the cutting amount of drilling and boring accounts for 17.5% of the blank mass. The cost is very high, and a large number of high-power drilling and boring machines are required, and the production is very uneconomical. If the secondary reaming process is used, the investment in the reaming machine needs to be increased, and the above problems will also occur, which will also lead to high cost and low efficiency.

At the same time, in the prior art, it is necessary to penetrate the extrusion needle into the inner hole of the blank after reaming, but in order to avoid scraping the glass lubricant in the inner hole of the blank when the extrusion needle penetrates, the inner diameter of the blank should be 12 larger than the diameter of the extrusion needle. ~15mm, which increases the loss of blank and the cost of reaming

In summary, there are many procedures, high cost and low efficiency in the process of extruding large-scale thin-walled pipes or hollow profiles in the prior art. Therefore, a kind of process can be shortened, costs can be reduced, and efficiency can be improved. The extrusion method of large-scale thin-walled pipe or hollow profile and its extrusion needle are the key to solving the existing technical problems

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