Internal thread core head with strengthened surface

Abstract

The utility model discloses a surface-strengthened internal thread core head, which is characterized in that a hardened layer is arranged on the surface of a thread tooth of the internal thread core head, the hardened layer consists of a first hardened layer or a second hardened layer, and the thickness of the first hardened layer on the tooth surface of the thread tooth is larger than that on a tooth groove, so that the hardened layer on the tooth surface is thicker. The tooth surfaces of the thread teeth are abraded faster than the tooth grooves, the thick hardened layers can protect the tooth surfaces against friction damage, the hardened layers are not prone to falling off and are reliable in structure, and meanwhile the thickness of the second hardened layer on the tooth surfaces of the thread teeth is larger than or equal to the thickness of the tooth grooves, so that the overall hardness of the internal thread core head is improved, and the abrasion resistance of the thread teeth is enhanced; and the phenomena of copper adhesion and tooth missing prematurely occurring in the use process of the internal thread core head are prevented, the problems of tooth residue, inner wall scratching and the like in the use process of the internal thread core head are reduced, and the service life of the internal thread core head is greatly prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of metal processing, in particular to an internal thread core head of an aluminum tube. Background Art

[0002] The internal thread core head is mainly used to generate threads inside aluminum tubes. The existing internal thread core head is usually made of cemented carbide material as a whole, and thread teeth are formed on the outer surface. During use, the wear resistance of the existing internal thread core head is insufficient, so that the tooth surface of the internal thread core head is easily worn out and scrapped, resulting in a short service life. At the same time, the tooth surface hardness of the existing internal thread core head is low. After a period of use, it is easy to have copper sticking and incomplete tooth shape, resulting in problems such as broken teeth and scratches on the inner wall of the seamless aluminum tube internal thread product.

[0003] A Chinese patent with publication number CN 104481997 A discloses an internal thread core head based on PVD surface strengthening, including an internal thread core head substrate, a surface of the internal thread core head substrate is provided with a plurality of thread teeth, and a surface of the thread teeth is provided with a PVD strengthening coating; the PVD strengthening coating is super hard, highly wear-resistant, and has a low friction coefficient, so that the surface hardness of the spiral teeth of the internal thread core head is increased to more than twice that of the substrate, thereby increasing the surface hardness of the spiral teeth of the internal thread core head and increasing the service life of the internal thread core head.

[0004] However, the PVD coating provided by the above scheme is prone to local wear and fall off during use. The tooth surface of the thread teeth, especially the R angle, will be subjected to higher pressure during use and there is high-speed metal flow, resulting in the fastest wear rate, while the wear rate of the inner surface of the tooth groove of the thread teeth is the slowest, resulting in reduced overall wear resistance of the internal thread core head, incomplete tooth shape, and friction with the pipe to scratch the inside of the pipe.

[0005] Therefore, how to effectively improve the surface hardness of the internal thread core head and enhance the surface wear resistance while ensuring that the structure is reliable and not easy to fall off has become an urgent problem to be solved in this field. Utility Model Content

[0006] In view of the defects of the prior art, the purpose of the utility model is to provide a surface-reinforced internal thread core head which has a reliable structure and effectively enhances the surface hardness and wear resistance.

[0007] In order to achieve the above-mentioned purpose, the utility model provides a surface-strengthened internal thread core head, wherein thread teeth are formed on the base of the internal thread core head, and the surface of the thread teeth is provided with a hardened layer, and the hardened layer is composed of a first hardened layer or a second hardened layer, and the thickness of the first hardened layer arranged on the tooth surface of the thread teeth is greater than the thickness arranged on the tooth groove of the thread teeth, and the thickness of the second hardened layer arranged on the tooth surface of the thread teeth is greater than or equal to the thickness arranged on the tooth groove of the thread teeth.

[0008] Furthermore, the first hardened layer is composed of a PVD coating, and the second hardened layer is composed of a wear-resistant hardened layer and a PVD coating.

[0009] Further, in the second hardened layer, the wear-resistant hardened layer is arranged between the thread teeth and the PVD coating.

[0010] Further, when the thickness of the second hardened layer disposed on the tooth surface of the thread tooth is equal to the thickness disposed on the tooth groove of the thread tooth, the thickness of the PVD coating in the second hardened layer is configured to be 3 to 5 microns.

[0011] Furthermore, the wear-resistant hardened layer is composed of a nickel-based alloy coating.

[0012] Furthermore, the thickness of the first hardened layer disposed on the thread tooth groove is 3 to 5 microns, and the thickness of the first hardened layer disposed on the thread tooth surface is 5 to 10 microns.

[0013] Furthermore, the base of the internal thread core head is made of cemented carbide.

[0014] The surface-reinforced internal thread core head provided by the present invention has a hardened layer on the surface of the thread teeth of the internal thread core head, and the hardened layer is composed of a first hardened layer or a second hardened layer, and is configured so that the thickness of the first hardened layer on the tooth surface of the thread teeth is greater than the thickness on the tooth groove, so that the hardened layer on the tooth surface is thicker. During use, the tooth surface of the thread teeth wears faster than the tooth groove. The thicker hardened layer can protect the tooth surface from friction damage, and the hardened layer is not easy to fall off, and the structure is reliable. At the same time, the thickness of the second hardened layer on the tooth surface of the thread teeth is greater than or equal to the thickness on the tooth groove, thereby improving the overall hardness of the internal thread core head, enhancing the wear resistance of the thread teeth, preventing the internal thread core head from prematurely sticking to copper and missing teeth during use, reducing the occurrence of problems such as residual teeth and inner wall scratches during use of the internal thread core head, and greatly improving the service life of the internal thread core head. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and specific implementations.

[0016] Attached Figure 1 and Figure 2 This is a structural schematic diagram of a first embodiment of the internal thread core head provided by the utility model.

[0017] Attached Figure 3 and Figure 4 This is a schematic structural diagram of a second embodiment of the internal thread core head provided by the utility model.

[0018] Attached Figure 5 This is a schematic structural diagram of a third embodiment of the internal thread core head provided by the utility model.

[0019] Reference numerals:

[0020] 1. Base; 2. Threaded teeth; 21. Tooth surface; 22. Tooth groove; 3. First hardened layer; 4. Second hardened layer; 41. Wear-resistant hardened layer; 411. Connecting groove; 42. PVD coating; 421. Connecting convex teeth. DETAILED DESCRIPTION

[0021] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0022] The surface-strengthened internal thread core head provided by the utility model is composed of a substrate 1, on which thread teeth 2 are formed, and a hardened layer is provided on the thread teeth 2, the hardened layer being composed of a first hardened layer 3 or a second hardened layer 4, the thickness of the first hardened layer 3 arranged on the tooth surface 21 of the thread teeth 2 being greater than the thickness arranged on the tooth groove 22 of the thread teeth 2, the thickness of the second hardened layer 4 arranged on the tooth surface 21 of the thread teeth 2 being greater than or equal to the thickness arranged on the tooth groove 22 of the thread teeth 2, so that the internal thread core head cooperates with the hardened layer to improve the overall hardness and wear resistance of the thread teeth 2, and the hardened layer is not easy to fall off, and the structure is reliable.

[0023] In order to illustrate the specific structure of the surface-strengthened internal thread core head provided by the present invention, an example is given below.

[0024] Embodiment 1

[0025] See also Figure 1 , which is a structural schematic diagram of a first embodiment of the internal thread core head provided by the utility model.

[0026] As can be seen from the figure, in this example, the surface of the thread teeth 2 on the substrate 1 is provided with a first hardened layer 3 to improve the hardness and wear resistance of the thread teeth 2 .

[0027] Specifically, the substrate 1 is preferably made of cemented carbide so that the substrate 1 has high strength and is suitable for precision machining, thereby forming thread teeth 2 on the outer surface of the substrate 1 .

[0028] Furthermore, the base 1 is used in conjunction with the aluminum tube, and the thread teeth 2 are rotationally cut on the aluminum tube. During the process of forming the internal thread of the aluminum tube, the thread teeth 2 will generate friction with the aluminum tube, so that the copper powder generated by the wear on the surface of the thread teeth 2 is sintered on the tooth surface 21 side of the thread teeth 2 and the bottom of the tooth groove 22, resulting in copper sticking, which leads to a decrease in the performance of the thread teeth 2, thereby resulting in low tooth height, smaller tooth top angle or missing teeth, etc., making the internal thread core head unable to be used normally.

[0029] In order to increase the service life of the internal thread core head and improve the hardness and wear resistance of the thread teeth 2 , a first hardened layer 3 is provided on the outer surface of the thread teeth 2 .

[0030] Furthermore, since the thread teeth 2 are rotationally cut on the aluminum tube to form the internal thread of the aluminum tube, the tooth surface 21 of the thread teeth 2 will be subjected to higher pressure during use and there is high-speed metal flow, resulting in the fastest wear rate of the tooth surface 21, causing the first hardened layer 3 on the tooth surface 21 to fall off, while the wear rate of the inner surface of the tooth groove 21 of the thread teeth 2 is the slowest, resulting in a decrease in the overall wear resistance of the substrate 1, resulting in incomplete tooth shape, and friction with the tube to scratch the inside of the tube.

[0031] Therefore, in Embodiment 1, the first hardened layer 3 is preferably composed of a PVD coating, and is configured such that the thickness on the tooth surface 21 of the threaded tooth 2 is greater than the thickness on the tooth groove 22. Since the PVD coating has high wear resistance and scratch resistance, it can effectively improve the hardness and wear resistance of the tooth surface 21, and the tooth surface 21 is not easily damaged by friction during use, resulting in incomplete tooth shape.

[0032] Furthermore, since a thicker first hardened layer 3 is disposed on the tooth surface 21 , the friction between the tooth surface 21 and the pipe is not likely to cause the first hardened layer 3 to fall off, thereby ensuring that the structure of the first hardened layer 3 is reliable.

[0033] As an example, when setting the first hardened layer 3, a PVD coating with a thickness of preferably 3-5 microns is firstly set on the entire thread tooth 2, so that the tooth groove 22 and the tooth surface 21 of the thread tooth 2 are provided with a PVD coating of uniform thickness. Then, another layer of PVD coating is set on the tooth surface 21, so that a PVD coating with a thickness of preferably 5-10 microns is formed on the tooth surface 21. As a result, the thickness of the first hardened layer 3 set on the tooth surface 21 of the thread tooth 2 is greater than the thickness set on the tooth groove 22, so as to improve the hardness and wear resistance of the tooth surface 21, prevent the tooth surface 21 from wear, and thus ensure the overall service life of the thread tooth 21.

[0034] Furthermore, compared with the uniform PVD coating with a thickness of 2-6 microns commonly used in the prior art, in this example, the thickness of the PVD coating provided on the tooth surface 21 is 5-10 microns, so as to effectively improve the hardness and wear resistance of the thread teeth 2, thereby improving the service life of the internal thread core head.

[0035] In the first embodiment, the internal thread core head is configured so that the cross section of the tooth surface 21 is approximately trapezoidal and the cross section of the tooth groove 22 is approximately triangular, so that the tooth surface 21 has a larger contact area than the tooth groove 22 and can withstand larger tensile and shear forces, thereby improving the wear resistance of the tooth surface 21.

[0036] In some embodiments, the internal thread core head can also be configured so that the cross-sections of the tooth surface 21 and the tooth groove 22 are both trapezoidal, such as Figure 2As shown, the tooth surface 21 and the tooth groove 22 can provide precise guidance and support for the pipe when friction cutting is performed on the pipe, thereby improving the accuracy of pipe cutting, while reducing friction with the pipe and increasing the service life of the internal thread core head.

[0037] Embodiment 2

[0038] In order to improve the overall hardness and wear resistance of the tooth surface 21 and the tooth groove 22 of the thread tooth 2 , on the basis of the first embodiment, in the second embodiment, a second hardened layer 4 is provided on the surface of the thread tooth 2 .

[0039] Further, see Figure 3 The second hardened layer 4 is preferably composed of a wear-resistant hardened layer 41 and a PVD coating 42, wherein the wear-resistant hardened layer 41 is arranged between the thread tooth 2 and the PVD coating 42, the wear-resistant hardened layer 41 is evenly arranged on the tooth surface 21 and the tooth groove 22, the PVD coating 42 is evenly arranged on the wear-resistant hardened layer 41, and the thickness is preferably 3 to 5 microns, so that the thickness of the second hardened layer 4 arranged on the tooth surface 21 of the thread tooth 2 is uniformly the same as the thickness arranged on the tooth groove 22, thereby forming two hardened layers on the surface of the thread tooth 2.

[0040] Here, the wear-resistant hardened layer 41 is preferably composed of a nickel-based alloy coating. Since the nickel-based alloy coating has good wear resistance and impact resistance, the nickel-based alloy coating can cooperate with the PVD coating 42 to improve the hardness and wear resistance of the surface of the thread teeth 2, so as to improve the wear resistance and impact resistance of the second hardened layer 4. Compared with the thread teeth 2 with only one layer of PVD coating, the nickel-based alloy coating can cooperate with the PVD coating 42 to improve the wear resistance by 50%.

[0041] Further, see Figure 4 In order to ensure the connection stability between the wear-resistant hardened layer 41 and the PVD coating 42 in the second hardened layer 4, the second hardened layer 4 can also be configured to have a connecting groove 411 formed on the top surface of the wear-resistant hardened layer 41, and a connecting convex tooth 421 matched with the connecting groove 411 formed on the bottom surface of the PVD coating 42, so that when the wear-resistant hardened layer 41 and the PVD coating 42 abut against each other, the connecting convex tooth 421 and the connecting groove 411 are meshed with each other, thereby improving the connection tightness between the wear-resistant hardened layer 41 and the PVD coating 42, so that the second hardened layer 4 has a stable structure and is not easy to fall off.

[0042] In some embodiments, the connecting grooves 411 are continuously and evenly distributed on the top surface of the wear-resistant hardened layer 41, and the connecting protrusions 421 are continuously and evenly distributed on the bottom surface of the PVD coating 42 and matched with the connecting grooves 411 to increase the connection area between the wear-resistant hardened layer 41 and the PVD coating 42 and improve the connection stability.

[0043] In some embodiments, the connecting grooves 411 are distributed at intervals on the top surface of the wear-resistant hardened layer 41, and the connecting protrusions 421 are distributed at intervals on the bottom surface of the PVD coating 42 and are adapted to the connecting grooves 411, so as to reduce the manufacturing cost of the wear-resistant hardened layer 41 and the PVD coating 42, while improving the connection stability.

[0044] Therefore, the tooth surface 21 and the tooth groove 22 of the thread tooth 2 are both provided with a second hardened layer 4 consisting of two hardened layers, which further improves the surface hardness and wear resistance of the thread tooth 2 and increases the service life.

[0045] Embodiment 3

[0046] See also Figure 5 On the basis of the second embodiment, the second hardened layer 4 can also be configured to have a thickness greater than that on the tooth groove 22 on the tooth surface 21 of the threaded tooth 2, thereby forming two hardened layers on the surface of the tooth surface 21 of the threaded tooth 2, and also having a second hardened layer 4 with a higher thickness on the tooth surface 21.

[0047] Specifically, the wear-resistant hardened layer 41 in the second hardened layer 4 is uniformly arranged on the tooth surface 21 and the tooth groove 22, the PVD coating 42 is arranged on the wear-resistant hardened layer 41, and the thickness of the PVD coating 42 arranged on the wear-resistant hardened layer 41 corresponding to the tooth surface 21 is greater than the thickness of the wear-resistant hardened layer 41 arranged on the tooth groove 22, so that the thickness of the second hardened layer 4 arranged on the tooth surface 21 of the threaded tooth 2 is greater than the thickness arranged on the tooth groove 22, so that the tooth surface 21 is protected by the wear-resistant hardened layer 41 of the thicker PVD coating 42, further improving the hardness and wear resistance, reducing the phenomenon of copper sticking and tooth missing, and preventing the occurrence of problems such as scratches on the inner wall of the pipe due to residual teeth during use.

[0048] The surface-strengthened internal thread core head provided by the utility model is provided with a first hardened layer 3 or a second hardened layer 4 on the surface of the thread teeth 2, and is configured so that the thickness of the first hardened layer 3 arranged on the tooth surface 21 is greater than the thickness on the tooth groove 22, and the thickness of the second hardened layer 4 arranged on the tooth surface 21 is greater than or equal to the thickness on the tooth groove 22, so that the surface hardness and wear resistance of the thread teeth 2 are improved, and the internal thread core head is prevented from prematurely sticking copper and missing teeth during use, and the generation of problems such as residual teeth and inner wall scratches during use of the internal thread core head is reduced, thereby greatly improving the service life of the internal thread core head.

[0049] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A surface-strengthened internal thread core head, wherein thread teeth are formed on the base of the internal thread core head, characterized in that: The surface of the thread tooth is provided with a hardened layer, and the hardened layer is composed of a first hardened layer or a second hardened layer. The thickness of the first hardened layer arranged on the tooth surface of the thread tooth is greater than the thickness arranged on the tooth groove of the thread tooth, and the thickness of the second hardened layer arranged on the tooth surface of the thread tooth is greater than or equal to the thickness arranged on the tooth groove of the thread tooth.

2. The surface-strengthened internal thread core head according to claim 1, characterized in that: The first hardened layer is composed of a PVD coating, and the second hardened layer is composed of a wear-resistant hardened layer and a PVD coating.

3. The surface-strengthened internal thread core head according to claim 2, characterized in that: In the second hardened layer, the wear-resistant hardened layer is arranged between the thread teeth and the PVD coating.

4. The surface-strengthened internal thread core head according to claim 3, characterized in that: When the thickness of the second hardened layer disposed on the tooth surface of the thread tooth is equal to the thickness disposed on the tooth groove of the thread tooth, the thickness of the PVD coating in the second hardened layer is configured to be 3 to 5 microns.

5. The surface-strengthened internal thread core head according to claim 3, characterized in that: The wear-resistant hardened layer is composed of a nickel-based alloy coating.

6. The surface-strengthened internal thread core head according to claim 1, characterized in that: The thickness of the first hardened layer disposed on the tooth groove of the thread tooth is 3 to 5 microns, and the thickness of the first hardened layer disposed on the tooth surface of the thread tooth is 5 to 10 microns.

7. The surface-strengthened internal thread core head according to claim 1, characterized in that: The matrix of the internal thread core head is made of cemented carbide.

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