A seamless steel pipe internal cooling plug

Abstract

The present invention proposes an internal cooling piercing head for a seamless steel pipe, comprising a main body, wherein the diameter of the front end of the main body gradually decreases to form an insertion section, the rear end of the main body is provided with a connecting portion, and the main body is provided with an internal cooling water channel spirally opened from back to front. When the internal cooling water channel approaches the front end of the insertion section, the spiral radius of the internal cooling water channel gradually decreases following the outline of the insertion 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 internal cooling water channel cross-section points in the radial direction of the main body; the pitch of the adjacent side surfaces of the internal cooling water channel is greater than the short diameter dimension of the internal cooling water channel cross-section and smaller than the long diameter dimension of the internal cooling water channel cross-section, and the spacing between the outer cavity wall of the internal cooling water channel and the outer walls of the main body and the insertion section is greater than or equal to the pitch of the internal cooling water channel. The present invention has the advantages of good radial support effect, good cooling effect, and long service life.

Description

Technical Field

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

[0002] During the production of existing seamless steel pipes, a piercing machine is used to pierce heated steel rods. During the piercing process, the plug is often subjected to high temperature and high pressure, resulting in a harsh working environment and accelerated wear of the plug. Therefore, some plugs are hollowed out to form a cavity inside for passing a cooling medium to cool the plug and extend its service life. However, the plug will bear a large radial load during operation, so it needs to have sufficient wall thickness for support. Increasing the wall thickness will reduce the cooling effect, while reducing the wall thickness will easily cause problems such as plug deformation during processing. Summary of the Invention

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

[0004] In response to the above problems, the following technical solutions are provided: a seamless steel pipe internal cooling plug, comprising a main body, wherein 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, and an internal cooling water channel is provided in the main body in a spiral shape from back to front, and the spiral radius of the internal cooling water channel gradually decreases following the outline of the top-in section when the internal cooling water channel is close to the front end of the top-in section; the cross section of the internal cooling water channel is waist-shaped or elliptical, and its aspect 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 wall 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, and the connecting part 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, water outlet and 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 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 side of the connecting seat facing the connecting thread forms a positioning surface; 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 made 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:

[0014] 1. The spirally opened inner cooling water channel is matched with its waist-shaped or elliptical cross-section, so that a strong radial support structure is formed between the inner cooling water channels, and the heat exchange area is also increased;

[0015] 2. The cooling medium is ejected from the water outlet in liquid or gaseous form after heat exchange through the water inlet and internal cooling water channel, blowing away the oxide layer between the working surfaces while protecting and reducing the external temperature of the main body;

[0016] 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, providing necessary technical support for the opening of internal cooling water channels;

[0017] 4. When a two-roller cross-rolling piercing machine is used for piercing, a cavity is easily formed in the center of the tube billet in front of the plug. However, a three-roller cross-rolling piercing machine can effectively avoid the formation of cavities. This plug is suitable for a three-roller cross-rolling piercing machine. The rolls of the three-roller cross-rolling piercing machine are arranged at 120 degrees, and the two water outlets are arranged at 180 degrees apart from each other. This can prevent the water outlets from being blocked during the extrusion and deformation of the billet during the piercing process.

[0018] 5. The base head is connected to the connector by welding, and then the connector is clamped on the fixture of the printing equipment. After printing is completed, the main body, the ejection section, and the connection part are fine-machined using the connector as a clamping reference. After the fine-machining is completed, the connector can be removed, which has the advantage of small material loss.

[0019] 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;

[0020] 7. The martensitic stainless steel grade is 17-4PH, which has high strength and toughness at up to 315℃ and excellent corrosion resistance, effectively ensuring the rigidity and connection strength between the plug and the ejector rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the first cutaway three-dimensional structure of the present invention.

[0023] Figure 3 It is a schematic diagram of a second cutaway three-dimensional structure of the present invention.

[0024] Figure 4 It is a schematic diagram of the third cutaway three-dimensional structure of the present invention.

[0025] Figure 5 This is a schematic structural diagram of the internal cooling water channel of the present invention from a first perspective (the internal cooling water channel, water outlet and water inlet are materialized for ease of observation).

[0026] Figure 6 This is a structural schematic diagram of the inner cooling water channel of the present invention from a second perspective (the inner cooling water channel, water outlet and water inlet are materialized for easier observation).

[0027] Figure 7 This is a structural schematic diagram of the inner cooling water channel of the present invention from a third perspective (the inner cooling water channel, water outlet and water inlet are materialized for easier observation).

[0028] The meaning of the numbers in the figure are: 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

[0029] The following embodiments of the present invention are described in further detail with reference to 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.

[0030] refer to Figures 1 to 7 ,like Figures 1 to 7The seamless steel pipe internal cooling plug shown in the figure includes 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 spirally opened 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 outline of the top section 11; the cross section of the internal cooling water channel 101 is waist-shaped or elliptical, and its aspect ratio is 2-4:1. The long diameter of the cross section of the internal cooling water channel 101 points in 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 pitch of 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 entry section 11 is greater than or equal to the pitch P of the inner cooling water channel 101; the top entry 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.

[0031] In the above structure, the spirally opened internal cooling water channel 101 is combined with its waist-shaped or elliptical cross-section to form a strong radial support organization between the internal cooling water channels 101, while also increasing the heat exchange area. The cooling medium passes through the water inlet 122 and the internal cooling water channel 101 and is ejected from the water outlet 102 in the form of liquid or gas after heat exchange, 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.

[0032] In this embodiment, there are two internal 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 180 degrees apart from each other; the rear ends of the two internal cooling water channels 101 are connected to the water inlet 122 through a transition water channel 123.

[0033] In the above structure, when the two-roller oblique rolling piercing machine pierces, a cavity is likely to appear in the center of the tube billet in front of its plug, 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 roller 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.

[0034] 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 side of the connecting seat 124 facing the connecting thread 121 forms a positioning surface 1241; the water inlet 122 is located in the center of the connecting part 12.

[0035] 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).

[0036] In this embodiment, the outer diameter of the connecting seat 124 is smaller than the outer diameter of the main body 10 .

[0037] In the above structure, the outer diameter difference is used to avoid contact with the inner wall of the perforated steel pipe.

[0038] 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.

[0039] 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 steel billet during the punching process on the water outlet 102.

[0040] In this embodiment, a chamfer 1021 is provided at the junction of the water outlet 102 and the outer wall of the top entry section 11 .

[0041] In the above structure, the strength of the junction is enhanced and stress concentration is reduced.

[0042] 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; during metal powder 3D printing, the base head 13 is used as an attachment basis for additive printing to form the ejection section 11 and the main body 10, and the additive powder selected for metal powder 3D printing is the same material as the base head 13.

[0043] 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 portion 12 are fine-machined using the connecting piece (not shown in the figure) as a clamping reference. After the fine-machined, the connecting piece (not shown in the figure) can be removed.

[0044] In this embodiment, the connection portion 12 is printed using martensitic stainless steel.

[0045] 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 connecting portion 12 and the connecting thread 121 thereof.

[0046] In this embodiment, the martensitic stainless steel grade is 17-4PH.

[0047] The above structure has high strength and toughness at temperatures as high as 315°C, and is highly corrosion-resistant, effectively ensuring the rigidity and connection strength between the mandrel and the mandrel (not shown in the figure).

[0048] 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 which gradually decreases in diameter to form a plugging section, and the rear end of which is provided with a connecting portion, characterized in that: The main body is provided with an internal cooling water channel which is opened in a spiral shape from back to front, and the spiral radius of the internal cooling water channel gradually decreases following the outline of the top entry section when the internal cooling water channel approaches the front end position of the top entry 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 pitch of the adjacent side surfaces of the internal cooling water channel is greater than the short diameter dimension of the cross section of the internal cooling water channel and smaller than the long diameter dimension of the cross section of the internal cooling water channel, and the spacing distance between the outer cavity wall of the internal cooling water channel and the outer wall of the main body and the top entry section is greater than or equal to the pitch of the internal 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 internal cooling water channel, and the connecting portion is provided with a connecting thread and a water inlet connected to the rear end of the internal cooling water channel; the main body is formed by metal powder 3D printing and the internal cooling water channel, water outlet and water inlet are constructed during the printing process; The connecting thread is an external thread and is located on the outer wall of the rear end of the connecting part; the connecting part also includes a connecting seat connected to the main body, and the side of the connecting seat facing the connecting thread forms a positioning surface; the water inlet is located in the center of the connecting part; 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.

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 2, characterized in that: The outer diameter of the connecting seat is smaller than the outer diameter of the main body.

4. The seamless steel pipe internal cold plug according to claim 3, characterized in that: A chamfer is provided at the junction of the water outlet and the outer wall of the top entry section.

5. A seamless steel pipe internal cold plug according to claim 1, 2, 3 or 4, 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. During metal powder 3D printing, the base head is used as an attachment foundation for additive printing to form the ejection section and the main body. The additive powder used in metal powder 3D printing is the same material as the base head.

6. The seamless steel pipe internal cold plug according to claim 5, characterized in that: The connection portion is printed using martensitic stainless steel.

7. The seamless steel pipe internal cold plug according to claim 6, characterized in that: The martensitic stainless steel grade is 17-4PH.

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