Seamless steel tube inner-cooling plug

Abstract

The seamless steel pipe inner cooling plug comprises a main body, the diameter of the front end of the main body is gradually reduced to form a jacking-in section, a connecting part is arranged at the rear end of the main body, and an inner cooling water channel which is spirally formed from back to front is formed in the main body; when the inner cold water channel is close to the front end of the jacking section, the spiral radius is gradually reduced along with the outline of the jacking section; the section of the inner cooling water channel is kidney-shaped or oval, the length-diameter ratio of the inner cooling water channel is 2-4: 1, and the long diameter of the section of the inner cooling water channel points to the radial direction of the body. The screw pitch of the adjacent side faces of the inner cooling water channel is larger than the short diameter of the section of the inner cooling water channel and smaller than the long diameter of the section of the inner cooling water channel, and the spacing distance between the outer side cavity wall of the inner cooling water channel and the outer wall of the body and the jacking-in section is larger than or equal to the screw pitch of the inner cooling water channel. The bearing has the advantages of being good in radial supporting effect, good in cooling effect and long in service life.

Description

Technical Field

[0001] The invention relates to the field of seamless steel pipe production equipment, in particular to an internally cooled plug for a seamless steel pipe. Background Art

[0002] In the production of existing seamless steel pipes, a puncher is used to punch holes in the heated steel rod. During the punching process, the plug is often subjected to high temperature and high pressure, so the working environment is harsh, which accelerates the wear of the plug. Therefore, some plugs are hollowed out to form a cavity for passing a cooling medium to cool the plug in order to extend the service life. However, the plug will bear a large radial load during operation, so it needs to have sufficient wall thickness for support. Thickening the wall thickness will reduce the cooling effect, while thinning the wall thickness will easily cause problems such as plug deformation during processing. Summary of the invention

[0003] Based on the above problems, the object of the present invention is to provide a seamless steel pipe internal cooling plug with good radial support effect, good cooling effect and long service life.

[0004] In view of the above problems, the following technical solutions are provided: a seamless steel pipe internal cooling head, comprising a main body, the diameter of the front end of the main body gradually decreases to form a top-in section, the rear end of the main body is provided with a connecting portion, the main body is provided with an internal cooling water channel opened in a spiral shape from back to front, when the internal cooling water channel is close to the front end of the top-in section, its spiral radius gradually decreases following the contour of the top-in section; the cross-section of the internal cooling water channel is waist-shaped or elliptical, and its length-to-short diameter ratio is 2-4:1, and the long diameter of the cross-section of the internal cooling water channel points to the radial direction of the main body; the internal cooling water channel is relatively The pitch of the adjacent side surface is greater than the short diameter dimension of the cross-section of the inner cooling water channel and smaller than the long diameter dimension of the cross-section of the inner cooling water channel. The spacing distance between the outer cavity wall of the inner cooling water channel and the outer walls of the main body and the top entry section is greater than or equal to the pitch of the inner cooling water channel. The top entry section is provided with a water outlet opened in a radial direction near the end position and connected to the front end of the inner cooling water channel. The connecting portion is provided with a connecting thread and a water inlet connected to the rear end of the inner cooling water channel. The main body is formed by metal powder 3D printing and the inner cooling water channel, the water outlet and the water inlet are constructed during the printing process.

[0005] The present invention is further configured such that there are two inner cooling water channels, which are arranged 180 degrees apart from each other along the circumferential direction of the main body, and the two water outlets are 180 degrees apart from each other; the rear ends of the two inner cooling water channels are connected to the water inlet through a transition water channel.

[0006] The present invention is further configured such that the connecting thread is an external thread and is located on the outer wall at the rear end of the connecting part; the connecting part also includes a connecting seat connected to the main body, and a positioning surface is formed on a side of the connecting seat facing the connecting thread; and the water inlet is located at the center of the connecting part.

[0007] The present invention is further configured such that the outer diameter of the connecting seat is smaller than the outer diameter of the main body.

[0008] The present invention is further configured such that the cross-section of the water outlet is waist-shaped or elliptical, with its short diameter facing the axial direction of the main body and its long diameter facing the circumferential direction of the main body or the spiral direction of the internal cooling water channel; the short diameter of the end of the water outlet away from the center of the main body remains unchanged while its long diameter gradually lengthens.

[0009] The present invention is further configured such that a chamfer is provided at the junction of the water outlet and the outer wall of the top entry section.

[0010] The present invention is further configured such that a base head is provided at the front end of the ejection section, and the base head is made of TZM alloy or TZC alloy; during metal powder 3D printing, additive printing is performed using the base head as an attachment basis to form the ejection section and the main body, and the additive powder selected for metal powder 3D printing is of the same material as the base head.

[0011] The present invention is further configured such that the connection portion is printed using martensitic stainless steel.

[0012] The present invention is further configured such that the martensitic stainless steel grade is 17-4PH.

[0013] Beneficial effects of the present invention: 1. The spirally opened inner cooling water channel cooperates with its waist-shaped or elliptical cross-section to form a strong radial support structure between the inner cooling water channels, while also increasing the heat exchange area; 2. The cooling medium is ejected from the water outlet in the form of liquid or gas after heat exchange through the water inlet and the internal cooling water channel, blowing away the oxide layer between the working surfaces and protecting and reducing the external temperature of the main body; 3. The main body is formed by metal powder 3D printing, which is conducive to the construction of complex water channels that cannot be formed by traditional mechanical processing, and provides necessary technical support for the opening of internal cooling water channels; 4. When the two-roller oblique rolling piercing machine is piercing, a cavity is easy to appear in the center of the tube billet in front of the plug, while the three-roller oblique rolling piercing machine can effectively avoid the appearance of cavity; this plug is suitable for the three-roller oblique rolling piercing machine. The roller detection of the three-roller oblique rolling piercing machine is arranged at 120 degrees, and the two water outlets are arranged at 180 degrees apart from each other. During the piercing process, the water outlet can be prevented from being blocked due to the extrusion and deformation of the billet; 5. The base head is connected to the connecting piece by welding, and then the connecting piece is clamped on the fixture of the printing equipment. After printing is completed, the main body, the top section and the connecting part are fine-processed by using the connecting piece as the clamping reference. After the fine processing is completed, the connecting piece can be removed, which has the advantage of small material loss; 6. The connection part is made of martensitic stainless steel, which can effectively reduce the use of TZM alloy or TZC alloy to reduce material costs, and also facilitate the finishing of the connection part and its connecting thread; 7. The martensitic stainless steel grade is 17-4PH, which still has high strength and toughness at up to 315°C, and has super corrosion resistance, effectively ensuring the rigidity and connection strength between the mandrel and the mandrel. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0015] Figure 2 It is a schematic diagram of the first cutaway three-dimensional structure of the present invention.

[0016] Figure 3 It is a schematic diagram of a second cutaway three-dimensional structure of the present invention.

[0017] Figure 4 It is a schematic diagram of a third cutaway three-dimensional structure of the present invention.

[0018] Figure 5 This is a schematic structural diagram of the inner cooling water channel of the present invention from a first perspective (the inner cooling water channel, the water outlet and the water inlet are materialized for easy observation).

[0019] Figure 6 This is a structural schematic diagram of the inner cooling water channel of the present invention from a second viewing angle (the inner cooling water channel, the water outlet and the water inlet are materialized for easy observation).

[0020] Figure 7 This is a schematic structural diagram of the inner cooling water channel of the present invention from a third viewing angle (the inner cooling water channel, the water outlet and the water inlet are materialized for easy observation).

[0021] The meaning of the numbers in the figure are as follows: 10-main body; 101-internal cooling water channel; 102-water outlet; 1021-rounded; 11-top entry section; 12-connecting part; 121-connecting thread; 122-water inlet; 123-transition water channel; 124-connecting seat; 1241-positioning surface; 13-base head. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] refer to Figures 1 to 7 ,like Figures 1 to 7The seamless steel pipe internal cooling head shown in the figure comprises a main body 10, the front end diameter of the main body 10 gradually decreases to form a top section 11, the rear end of the main body 10 is provided with a connecting portion 12, and the main body 10 is provided with an internal cooling water channel 101 which is opened in a spiral shape from back to front. When the internal cooling water channel 101 is close to the front end of the top section 11, its spiral radius gradually decreases following the contour of the top section 11; the cross section of the internal cooling water channel 101 is waist-shaped or elliptical, and its length-to-short diameter ratio is 2-4:1, and the cross section of the internal cooling water channel 101 points to the radial direction of the main body 10; the pitch P of the adjacent side surfaces of the internal cooling water channel 101 is greater than the internal cooling water channel 101. The short diameter dimension S of the cross section is smaller than the long diameter dimension L of the cross section of the inner cooling water channel 101, and the spacing distance H between the outer cavity wall of the inner cooling water channel 101 and the outer walls of the main body 10 and the top section 11 is greater than or equal to the pitch P of the inner cooling water channel 101; the top section 11 is provided with a water outlet 102 opened in a radial direction near the end position and connected to the front end of the inner cooling water channel 101, and the connecting portion 12 is provided with a connecting thread 121 and a water inlet 122 connected to the rear end of the inner cooling water channel 101; the main body 10 is formed by metal powder 3D printing and the inner cooling water channel 101, the water outlet 102 and the water inlet 122 are constructed during the printing process.

[0024] In the above structure, the spirally opened internal cooling water channel 101 cooperates with its waist-shaped or elliptical cross-section, so that a strong radial supporting organization is formed between the internal cooling water channels 101, and the heat exchange area is also increased. The cooling medium is ejected from the water outlet 102 in the form of liquid or gas after heat exchange through the water inlet 122 and the internal cooling water channel 101, blowing away the oxide layer between the working surfaces, while protecting and reducing the external temperature of the main body 10; the main body 10 is formed by metal powder 3D printing, which is conducive to the construction of complex water channels that cannot be formed by traditional mechanical processing, and provides necessary technical support for the opening of the internal cooling water channel 101.

[0025] In this embodiment, there are two inner cooling water channels 101, which are arranged 180 degrees apart from each other along the circumferential direction of the main body 10, and the two water outlets 102 are spaced 180 degrees apart from each other; the rear ends of the two inner cooling water channels 101 are connected to the water inlet 122 through a transition water channel 123.

[0026] In the above structure, a cavity is likely to appear in the center of the tube billet in front of the plug of the two-roller oblique rolling piercing machine when piercing, while the three-roller oblique rolling piercing machine can effectively avoid the appearance of the cavity; this plug is suitable for the three-roller oblique rolling piercing machine, the roll detection of the three-roller oblique rolling piercing machine is arranged at 120 degrees, and the two water outlets 102 are arranged at 180 degrees apart from each other, which can avoid the water outlet 102 from being blocked during the extrusion and deformation of the steel billet during the piercing process.

[0027] In this embodiment, the connecting thread 121 is an external thread and is located on the outer wall of the rear end of the connecting part 12; the connecting part 12 also includes a connecting seat 124 connected to the main body 10, and the connecting seat 124 forms a positioning surface 1241 on a side facing the connecting thread 121; the water inlet 122 is located at the center of the connecting part 12.

[0028] In the above structure, the connecting portion 12 is used to be connected to a top rod (not shown in the figure), and a channel (not shown in the figure) for supplying water to the water inlet 122 is provided in the center of the top rod (not shown in the figure).

[0029] In this embodiment, the outer diameter of the connecting seat 124 is smaller than the outer diameter of the main body 10 .

[0030] In the above structure, the difference in outer diameters prevents the steel pipe from contacting the inner wall of the perforated steel pipe.

[0031] In this embodiment, the cross-section of the water outlet 102 is waist-shaped or elliptical, with its short diameter S1 facing the axial direction of the main body 10 and the long diameter L1 facing the circumferential direction of the main body 10 or the spiral direction of the internal cooling water channel 101; the short diameter S1 of the end of the water outlet 102 away from the center of the main body 10 remains unchanged while its long diameter L1 gradually lengthens.

[0032] In the above structure, the size of the water outlet 102 in the circumferential direction is lengthened to reduce the impact of the extrusion deformation of the billet during the punching process on the water outlet 102.

[0033] In this embodiment, a chamfer 1021 is provided at the junction between the water outlet 102 and the outer wall of the top entry section 11 .

[0034] In the above structure, the strength of the junction is enhanced and stress concentration is reduced.

[0035] In this embodiment, a base head 13 is provided at the front end of the ejection section 11, and the base head 13 is TZM alloy or TZC alloy. When metal powder 3D printing is performed, the base head 13 is used as an attachment basis for additive printing to form the ejection section 11 and the main body 10. The additive powder selected for metal powder 3D printing is of the same material as the base head 13.

[0036] In the above structure, the base head 13 is connected to the connecting piece (not shown in the figure) by welding, and then the connecting piece (not shown in the figure) is clamped on the fixture of the printing device. After printing is completed, the main body 10, the ejection section 11, and the connecting part 12 are fine-processed by using the connecting piece (not shown in the figure) as a clamping reference. After the fine processing is completed, the connecting piece (not shown in the figure) can be removed.

[0037] In this embodiment, the connection portion 12 is printed using martensitic stainless steel.

[0038] In the above structure, the usage of TZM alloy or TZC alloy can be effectively reduced to reduce material cost, and it is also convenient to perform fine processing on the connection part 12 and the connection thread 121 thereof.

[0039] In this embodiment, the martensitic stainless steel grade is 17-4PH.

[0040] The above structure has high strength and toughness at a temperature as high as 315°C, and has super corrosion resistance, which effectively ensures the rigidity and connection strength between the mandrel and the mandrel (not shown in the figure).

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications of the above assumptions should also be regarded as the scope of protection of the present invention.

Claims

1. A seamless steel pipe internal cold plug, comprising a main body, the front end of the main body gradually reduces in diameter to form a plug-in section, and the rear end of the main body is provided with a connecting portion, characterized in that: The main body is provided with an inner cooling water channel which is opened in a spiral shape from back to front, and when the inner cooling water channel is close to the front end of the top entry section, its spiral radius gradually decreases following the contour of the top entry section; the cross-section of the inner cooling water channel is waist-shaped or elliptical, and its length-to-short diameter ratio is 2-4:1, and the long diameter of the cross-section of the inner cooling water channel points to the radial direction of the main body; the pitch of the adjacent side surfaces of the inner cooling water channel is greater than the short diameter dimension of the cross-section of the inner cooling water channel and smaller than the long diameter dimension of the cross-section of the inner cooling water channel, and the spacing distance between the outer cavity wall of the inner cooling water channel and the outer walls of the main body and the top entry section is greater than or equal to the pitch of the inner cooling water channel; the top entry section is provided with a water outlet opened in the radial direction near the end position and connected to the front end of the inner cooling water channel, and the connecting portion is provided with a connecting thread and a water inlet connected to the rear end of the inner cooling water channel; the main body is formed by metal powder 3D printing and the inner cooling water channel, the water outlet and the water inlet are constructed during the printing process.

2. The seamless steel pipe internal cold plug according to claim 1, characterized in that: There are two inner cooling water channels, which are arranged 180 degrees apart from each other along the circumferential direction of the main body, and the two water outlets are 180 degrees apart from each other; the rear ends of the two inner cooling water channels are connected to the water inlet through a transition water channel.

3. The seamless steel pipe internal cold plug according to claim 1, characterized in that: The connecting thread is an external thread, which is located on the outer wall at the rear end of the connecting part; the connecting part also includes a connecting seat connected to the main body, and a positioning surface is formed on a side of the connecting seat facing the connecting thread; the water inlet is located at the center of the connecting part.

4. The seamless steel pipe internal cold plug according to claim 3, characterized in that: The outer diameter of the connecting seat is smaller than the outer diameter of the main body.

5. The seamless steel pipe internal cold plug according to claim 1, characterized in that: The cross section of the water outlet is waist-shaped or elliptical, with its short diameter facing the axial direction of the main body and its long diameter facing the circumferential direction of the main body or the spiral direction of the internal cooling water channel; the short diameter of the end of the water outlet away from the center of the main body remains unchanged while its long diameter gradually lengthens.

6. The seamless steel pipe internal cold plug according to claim 5, characterized in that: A chamfer is provided at the junction of the water outlet and the outer wall of the top entry section.

7. A seamless steel pipe internal cold plug according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that: A base head is provided at the front end of the ejection section, and the base head is made of TZM alloy or TZC alloy. When metal powder is 3D printed, the base head is used as an attachment basis for additive printing to form the ejection section and the main body. The additive powder selected for metal powder 3D printing is the same material as the base head.

8. The seamless steel pipe internal cold plug according to claim 7, characterized in that: The connection portion is printed using martensitic stainless steel.

9. The seamless steel pipe internal cold plug according to claim 8, characterized in that: The martensitic stainless steel grade is 17-4PH.

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