A high-efficiency cooling piercing head connecting lock and a piercing head matched therewith

Abstract

The utility model relates to a kind of efficient cooling's top head connecting lock joint and the perforating top head of its matched use, including lock body, the lock body includes middle part step round seat, front connecting section and rear connecting section, the rear connecting section is internally provided with the cooling water inlet cavity with opening rear, the front connecting section is internally provided with the top head cooling water channel with opening front, the top head cooling water channel is communicated with cooling water inlet cavity, the middle part step round seat is radially provided with cooling water outlet, the cooling water outlet is communicated to between top head cooling water channel and cooling water inlet cavity, and the top head inner cavity of perforating top head's top head base is internally provided with opening rear and top head cooling water channel of the lock body is connected with top head inner cavity, the utility model enables cooling water to enter from lock rear end, directly flows into top head interior and cools down by channel, effectively reduces top head operating temperature, inhibits its high-temperature deformation and surface wrinkled skin, to extend service life and improve the quality of perforated pipe inner wall.

Description

Technical Field

[0001] This utility model relates to the technical field of seamless steel pipe perforation components, and in particular to a high-efficiency cooling mandrel connection locking joint and its matching perforation mandrel. Background Technology

[0002] In the metallurgical industry, especially in the production of stainless steel seamless pipes, hot piercing is one of the key forming processes. Currently, the skew rolling piercing process is commonly used. Its basic principle is to feed a round steel billet heated to 1050–1250℃ into a piercing mill consisting of a pair of high-speed rotating rolls. Under the interlocking action of the rolls, the billet rotates and moves axially forward while being guided by a mandrel at the front end to form an inner hole, thus completing the piercing process.

[0003] As a core component in the piercing process, the mandrel comes into direct contact with the inner wall of the high-temperature tube blank and endures intense friction. During continuous operation, the same mandrel often needs to process 7 tons or more of high-temperature tube blanks, and its working environment is extremely harsh. On the one hand, the high-temperature heat carried by the tube blank itself is continuously conducted to the mandrel; on the other hand, the friction between the mandrel and the tube blank further aggravates the temperature rise. Under prolonged high-temperature conditions, the surface of the mandrel is highly susceptible to thermal damage such as oxidation and wrinkling (commonly known as "skinning").

[0004] In existing technologies, to control the operating temperature of the mandrel, a circulating cooling water channel is typically installed inside the locking joint connected to it, cooling the mandrel through indirect heat conduction. However, this cooling structure has significant shortcomings: the cooling water only flows through the inside of the locking joint and does not directly contact the mandrel body; furthermore, the actual heat conduction contact area between the locking joint and the mandrel is limited, resulting in low overall heat transfer efficiency. Under high-load, long-term continuous production conditions, this indirect cooling method is insufficient to effectively suppress the rapid rise in mandrel temperature and cannot adequately guarantee the thermal stability of the mandrel.

[0005] The resulting problem is that an overheated mandrel not only has a significantly shortened lifespan, but also causes the inner wall roughness of the tube blank to exceed the standard during the piercing process. In severe cases, it can even induce defects such as fine cracks on the inner surface, which in turn affects subsequent rolling processes, causing quality problems such as tube cracking and scrapping, increasing production costs and reducing equipment operating efficiency.

[0006] Therefore, there is an urgent need for a structural improvement scheme that can effectively improve the cooling efficiency of the mandrel, in order to solve the technical problems of insufficient cooling effect, easy damage to the mandrel, and unstable product quality in the existing technology. Utility Model Content

[0007] This invention proposes a highly efficient cooling mandrel connection locking joint and a matching perforated mandrel, which solves the aforementioned problems existing in the prior art.

[0008] The technical solution of this utility model is implemented as follows: a high-efficiency cooling top connection locking joint includes a locking joint body, the locking joint body including a central stepped circular seat, a front connecting section and a rear connecting section, the rear connecting section having a rearward-facing cooling water inlet cavity, the front connecting section having a front-facing top cooling water channel, the top cooling water channel communicating with the cooling water inlet cavity, the central stepped circular seat having a radially penetrating cooling water outlet, the cooling water outlet communicating between the top cooling water channel and the cooling water inlet cavity.

[0009] Preferably, a first annular water groove is provided on the front side of the central stepped circular seat, and two return water ports are symmetrically provided in the first annular water groove, which respectively penetrate to both ends of the cooling water outlet.

[0010] Preferably, both the front connecting section and the rear connecting section have external threads on their outer side walls.

[0011] In addition, this utility model also discloses a perforated mandrel for use with a high-efficiency cooling mandrel connecting locking joint, which is used to be installed on the locking joint body of the high-efficiency cooling mandrel connecting locking joint. It includes a mandrel base and a reinforcing alloy head. The reinforcing alloy head is welded and fixed to the front end of the mandrel base. The mandrel base is connected to the front connecting section of the locking joint body. The mandrel base has a mandrel inner cavity with an opening facing rearward and communicating with the mandrel cooling water channel of the locking joint body.

[0012] Preferably, the top head base has a second annular water groove corresponding to the first annular water groove of the locking body, the second annular water groove is connected to the first annular water groove, and a cooling water channel penetrating into the top head base and connecting to the front end of the top head cavity is formed in the second annular water groove.

[0013] Preferably, the cooling water channels are arranged circumferentially at equal intervals, with at least four channels.

[0014] Preferably, the mandrel base has an internal threaded hole, and the mandrel base is threadedly connected to the front connecting section of the locking body through the internal threaded hole.

[0015] In summary, the beneficial effects of this utility model are as follows: 1. By incorporating interconnected cooling water inlet chambers, mandrel cooling water channels, and radially penetrating the central stepped circular seat within the locking joint body, cooling water can enter from the rear end of the locking joint, flow directly into the mandrel for cooling, and efficiently exit through the radial outlet, achieving direct, through-flow cooling of the mandrel. This structure significantly increases the contact area and heat exchange efficiency between the coolant and the mandrel, effectively reducing the mandrel's operating temperature, suppressing high-temperature deformation and surface wrinkling, thereby extending its service life and improving the quality of the perforated pipe's inner wall.

[0016] 2. This perforated mandrel is used in conjunction with the aforementioned high-efficiency cooling lock joint. Its mandrel base has an internal cavity that communicates with the cooling water channel of the lock joint mandrel, allowing cooling water to directly enter the mandrel for forced cooling. Combined with the reinforced alloy head at the front end, it retains the high-temperature wear resistance of the mandrel's front end while effectively controlling the overall temperature through internal water cooling. This solves the problem of insufficient heat dissipation caused by traditional mandrels relying solely on external indirect cooling, significantly improving the mandrel's thermal stability and service life.

[0017] 3. By setting a second annular water tank in the mandrel base that connects to the first annular water tank of the locking joint, and opening a cooling water channel connecting to the front end of the mandrel's inner cavity, a closed-loop cooling circuit is constructed: cooling water flows from the mandrel's inner cavity through the cooling water channel to the rear annular tank, and then flows back to the locking joint for discharge. This structure achieves full-process, multi-point cooling of the mandrel from the front end to the rear end, especially enhancing the heat dissipation capacity of the front end area, which is most prone to overheating, significantly improving the uniformity of temperature distribution, and effectively preventing local overheating failure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a front view of the locking joint body in this utility model; Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure along the AA direction; Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure along the BB direction; Figure 4 This is a perspective view of the locking joint body in this utility model; Figure 5 This is a perspective view of the perforated top head in this utility model; Figure 6 This is a cross-sectional structural diagram of the perforated mandrel assembled on the locking body in this utility model.

[0020] In the diagram: 1. Locking joint body; 2. Middle stepped circular seat; 21. Cooling water outlet; 22. First annular water tank; 23. Return water inlet; 3. Front connecting section; 31. Cooling water channel of the mandrel; 4. Rear connecting section; 41. Cooling water inlet cavity; 5. External thread; 6. Mandrel base; 61. Mandrel inner cavity; 62. Second annular water tank; 63. Cooling water channel; 64. Internal threaded hole; 7. Reinforcing alloy head; 8. Sealing ring; 9. Sealed return water cavity. Detailed Implementation

[0021] The following will refer to the appendix in the embodiments of this utility model. Figure 1-6 The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] Example: like Figures 1 to 4 As shown, this utility model discloses a high-efficiency cooling mandrel connection locking joint and a matching perforating mandrel, mainly used in the hot piercing process of stainless steel seamless pipes in the metallurgical industry. It aims to solve problems such as surface wrinkling, short lifespan, and poor inner wall quality of traditional mandrels due to high temperatures. This structure achieves efficient, uniform, and direct cooling of the mandrel from front to back end by optimizing the internal cooling water path of the locking joint and coordinating it with the internal cooling channel of the mandrel.

[0023] The locking joint body 1 has an overall axisymmetric structure, consisting of three parts: a central stepped circular seat 2, a front connecting section 3, and a rear connecting section 4, which are integrally formed or precision machined from high-strength alloy materials. The rear connecting section 4 connects to the piercing machine core rod and has a rearward-opening cooling water inlet cavity 41, through which cooling water enters the locking joint. The front connecting section 3 connects to the piercing mandrel and has an axially opening mandrel cooling water channel 31. This channel communicates with the rear cooling water inlet cavity 41 within the locking joint, forming the main flow path for cooling water. A cooling water outlet 21 is provided radially through the central stepped circular seat 2. This outlet is located in the communication area between the cooling water inlet cavity 41 and the mandrel cooling water channel 31, and is used to discharge the cooled water after heat exchange to the outside of the locking joint, achieving cooling circulation.

[0024] To further improve water return efficiency and cooling uniformity, a first annular water groove 22 is machined on the front end face of the central stepped circular base 2. This annular water groove connects with a second annular water groove 62 on the subsequent top head base 6 to form a sealed annular water return cavity 9. Two return water ports 23 are symmetrically opened in the first annular water groove 22, respectively connected to both ends of the cooling water outlet 21, so that the cooling water can flow back evenly from both sides and flow out quickly from both ends of the cooling water outlet 21.

[0025] Both the front connecting section 3 and the rear connecting section 4 have external threads 5 machined on their outer side walls. The external thread 5 of the rear connecting section 4 is used to mate with the internal thread of the piercing machine core rod to achieve quick installation and fixation of the locking joint on the equipment; the external thread 5 of the front connecting section 3 is used to connect with the internal threaded hole 64 of the mandrel base 6 to ensure a firm connection and good sealing between the mandrel and the locking joint, preventing leakage of high-temperature and high-pressure cooling water during operation.

[0026] In addition, such as Figure 5 and Figure 6 As shown, this utility model also discloses a matching perforated mandrel, which is used to install on the locking body 1 of the mandrel connecting locking joint with high-efficiency cooling. It includes a mandrel base 6 and a reinforcing alloy head 7. The mandrel base 6 is typically made of heat-resistant steel or high-temperature alloy, and its front end is welded and fixed with a reinforcing alloy head 7 made of molybdenum or molybdenum alloy to withstand direct friction and thermal shock with the high-temperature tube blank during the perforation process. The rear end of the mandrel base 6 has an internal threaded hole 64 that matches the external thread 5 of the front connecting section 3 of the locking joint, achieving a threaded connection. Inside the mandrel base 6, an axially opening rearward-facing mandrel inner cavity 61 is formed. This inner cavity is directly connected to the mandrel cooling water channel 31 of the locking joint after connection, allowing cooling water to flow from the locking joint into the mandrel interior.

[0027] A second annular water groove 62 is formed on the end face of the mandrel base 6 near the connection with the locking joint. Its position is precisely aligned with the first annular water groove 22 on the locking joint, forming a closed annular return water cavity 9 after assembly. Sealing rings 8 are provided on both sides of the first and second annular water grooves 22 and 62 between the mandrel base 6 and the connecting locking joint. At least four cooling water channels 63 are circumferentially spaced on the inner wall of the second annular water groove 62. These cooling water channels 63 extend axially forward, penetrating into the interior of the mandrel base 6 and ultimately connecting to the front end region of the mandrel inner cavity 61. Cooling water flows in from the cooling water inlet 41 of the locking joint, enters the mandrel inner cavity 61 through the mandrel cooling water channel 31, then flows backward through each cooling water channel 63 from the front end into the second annular water groove 62, then flows into the first annular water groove 22 of the locking joint, and finally flows out through the return water port 23 into the cooling water outlet 21.

[0028] This cooling path enables a "forward-backward" circulation of cooling water within the mandrel: the cooling water first enters the highest-temperature region at the front end of the mandrel for direct cooling, and then flows back evenly to the rear annular groove through multiple circumferentially distributed cooling channels 63, effectively removing heat. This multi-channel, annular backflow cooling method from front to rear significantly improves cooling efficiency and temperature distribution uniformity, effectively suppressing problems such as oxidation, wrinkling, and cracking caused by localized overheating of the mandrel.

[0029] In practical use, the highly efficient cooling mandrel connecting locking joint is assembled with the piercing mandrel and installed at the front end of the hot piercing mill mandrel. Cooling water is introduced by an external water pump through pipelines into the cooling water inlet chamber 41 at the rear end of the locking joint, flowing sequentially through the mandrel cooling water channel 31, the mandrel inner cavity 61, the cooling water channel 63, and the annular water tank, and finally discharged from the cooling water outlet 21, forming a closed or open cooling cycle. The entire system can maintain a stable mandrel temperature even when continuously piercing high-temperature billets weighing over 7 tons, significantly extending the mandrel's service life and significantly improving the surface quality of the inner wall of the pierced billet, reducing defects such as cracking during subsequent rolling processes.

[0030] It should also be noted that the terms used in this utility model, such as "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-efficiency cooling mandrel connector, comprising a connector body, characterized in that: The locking body includes a central stepped circular seat, a front connecting section, and a rear connecting section. The rear connecting section has a rearward-facing cooling water inlet cavity, and the front connecting section has a front-facing top cooling water channel. The top cooling water channel communicates with the cooling water inlet cavity. The central stepped circular seat has a radially penetrating cooling water outlet, which connects to the space between the top cooling water channel and the cooling water inlet cavity.

2. The high-efficiency cooling mandrel connection lock according to claim 1, characterized in that: A first annular water trough is provided on the front side of the central stepped circular seat, and two return water ports are symmetrically arranged in the first annular water trough, which respectively pass through to both ends of the cooling water outlet.

3. The high-efficiency cooling mandrel connection locking joint according to claim 1, characterized in that: External threads are provided on the outer side walls of both the front and rear connecting sections.

4. A perforated mandrel for use with a high-efficiency cooling mandrel connecting locking joint, characterized in that: For use in conjunction with the locking body of the high-efficiency cooling mandrel connecting locking joint as described in claim 3, it includes a mandrel base and a reinforcing alloy head. The reinforcing alloy head is welded and fixed to the front end of the mandrel base. The mandrel base is connected to the front connecting section of the locking joint body. The mandrel base has a mandrel inner cavity with an opening facing rearward and communicating with the mandrel cooling water channel of the locking joint body.

5. A perforated mandrel for use with a high-efficiency cooling mandrel connecting locking joint according to claim 4, characterized in that: The top head base is provided with a second annular water groove corresponding to the first annular water groove of the locking body. The second annular water groove is connected to the first annular water groove. A cooling water channel is provided in the second annular water groove that penetrates into the top head base and connects to the front end of the top head cavity.

6. The perforated mandrel for use with a high-efficiency cooling mandrel connecting locking joint according to claim 5, characterized in that: The cooling water channels are arranged circumferentially at equal intervals, with at least four channels.

7. A perforated mandrel for use with a high-efficiency cooling mandrel connecting locking joint according to claim 4, characterized in that: The mandrel base has an internal threaded hole, and the mandrel base is threadedly connected to the front connecting section of the locking body through the internal threaded hole.

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