Combined petroleum pipe thread cutter

Abstract

The utility model relates to the technical field of petroleum pipe thread machining, and discloses a combined petroleum pipe thread tool which comprises a finish turning tool and a rough turning tool. The finish turning tool and the rough turning tool are both butterfly-shaped structure main bodies; mounting holes are formed in the middles of the cutter bodies; at most two cutting edges are arranged in the circumferential direction of the cutter body; each cutting edge is provided with at most four cutting teeth; compared with corresponding parameter sizes of a finish turning tool, a finish turning tooth arc in cutting teeth of the rough turning tool is increased by a first proportion, a rough turning tooth arc is increased by a second proportion, tooth height of a tooth profile is reduced by a third proportion, a rake face angle is reduced by a fourth proportion, and a cutting edge passivation arc is increased; and the rough turning tool adopts a coating different from the finish turning tool in type. According to the combined tool, the rough turning tool is mainly used for removing most of allowance and bearing more impact, the finish turning tool is used for finish trimming to guarantee the tool precision and the machining quality, rough turning is stable, finish turning is durable, the stability of the machining process is improved, and the relative machining efficiency and the service life of the tool are guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil pipe thread processing technical field, concretely relates to a combined oil pipe thread cutter. BACKGROUND

[0002] Traditional oil pipe thread processing pays attention to the balance of efficiency, quality and tool life, and emphasizes using fewer tools to process the same product, does not advocate too many stations to save conversion time, and usually uses one cutter to solve one process, such as using one cutter to walk 5-15 times to complete thread processing.

[0003] However, with the continuous rise of the steel grade of the workpiece, from J55 to P110, and from P110 to 125ksi, 140ksi high-strength steel, the material hardness and strength increase significantly, resulting in a significant increase in cutting difficulty and cutting force, thereby accelerating the wear of the cutter, making it increasingly difficult to maintain the balance between processing efficiency and tool life while ensuring processing efficiency and prolonging tool life at low cost, making it very difficult to complete thread processing with one cutter at high speed, and random collapse and tool breakage make it difficult to maintain the balance between processing efficiency and tool life, and the processing quality cannot be guaranteed. SUMMARY

[0004] The utility model intends to provide a combined oil pipe thread cutter to solve the technical problem that the steel grade of the workpiece is continuously rising, the balance between processing efficiency and tool life is difficult to maintain, and it is difficult to complete oil pipe thread processing with one cutter at high speed.

[0005] The basic scheme provided by the utility model is: a combined oil pipe thread cutter, comprising at least one finish cutter and at least one roughing cutter; the main body structure of the finish cutter and the roughing cutter is the same, and the parameter size and the coating layer are different;

[0006] The main body structure comprises a cutter body with a butterfly structure; an installation hole is arranged in the middle of the cutter body; at most two cutting edges are arranged along the circumference of the cutter body; and at most four cutting teeth are arranged on each cutting edge;

[0007] The parameter size difference comprises that, compared with the corresponding parameter size of the finish cutter, the finish tooth arc in the cutting tooth of the roughing cutter increases by a first proportion, the rough tooth arc increases by a second proportion, the tooth height of the tooth shape decreases by a third proportion, the rake angle decreases by a fourth proportion, and the blade edge blunt arc is increased;

[0008] The coating layer difference comprises that the hardness and wear resistance of the coating layer used by the roughing cutter are higher than the hardness and wear resistance of the coating layer used by the finish cutter.

[0009] The utility model discloses a working principle and the advantage lies in: the combined tool of the scheme is used in the specific, and the roughing tool and the finishing tool are installed at the adjacent different stations respectively, and each tool occupies a tool bar, and the rotational speed and other specific processing parameters remain unchanged, the roughing tool is used for more times, and the finishing tool is used for less times.

[0010] Compared with the prior art, the scheme changes the traditional idea of one tool with multiple functions, adopts the mode of converting and using combined tools, removes most of the excess amount with the roughing tool under relatively high spindle speed, bears more impact, and finishes and refines with the finishing tool to ensure accuracy and processing quality, so that the combined tool system achieves the effect of "stable roughing and durable finishing", and can greatly reduce the probability of tool collapse and tool breaking. Although the switching time is increased in the combined use of the roughing tool and the finishing tool compared with the one tool with multiple functions, the scheme optimizes the structure of the roughing tool to bear most of the excess amount, reduces the risk of the finishing tool, and improves the stability and service life of the combined tool. In the long term, the effective use of a set of tools is ensured, the number of tool replacement is reduced, the switching time of the roughing tool and the finishing tool is effectively made up, the processing efficiency is ensured, and the beneficial effects of improving process stability and ensuring relative processing efficiency and tool service life are realized as a whole, and the effective balance of efficiency and service life is realized.

[0011] The combined petroleum pipe thread tool in the scheme keeps the finishing tool unchanged, adds the roughing tool mainly used for removing most of the excess amount and bearing more impact, the roughing tool and the finishing tool have the same main structure, the number of cutting edges and teeth is unchanged, the roughing tool parameters are optimized on the basis of the finishing tool, 1) the tooth profile is optimized, the arc in the roughing tool finishing tooth and roughing tooth profile is increased to improve the impact resistance, so that it can bear strong impact, the tooth height in the tooth profile is reduced to reduce the risk of tool breaking, and the rake angle is reduced, so that the negative rake angle is processed under the condition that the tool body is unchanged, and the tool tip strength is improved, 2) the micro passivation zone is increased to enhance the tool tip strength, the blade edge passivation arc is increased to reduce the probability of tool edge collapse, and 3) the roughing tool changes the CVD coating, the thicker coating greatly improves the wear resistance, and can also protect the tool tip, the roughing tool no longer uses the same coating (such as physical vapor deposition PVD coating) as the finishing tool, but uses a coating (such as chemical vapor deposition CVD coating) with higher hardness and wear resistance, and the tool service life is further improved.

[0012] Different from the simultaneous cutting of pipe body external threads by multiple tools in traditional thread processing, the new, simple and efficient combined petroleum pipe thread tool is used to remove most of the excess amount by the roughing tool first, and then the finishing tool is used for finishing, the requirement for the machine tool is low, the machine tool does not need to be up and down or multi-axis linkage, is suitable for ordinary tool holder type and tool disc type machine tools, the roughing tool and the finishing tool run respectively, the accuracy requirement is general, and the application range is wide. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structure schematic view of a typical cutter with 2 blades and 3 teeth;

[0014] Figure 2 is a parameter schematic view of API standard 8 teeth per inch round thread tooth profile;

[0015] Figure 3 is a size difference schematic view of the finishing cutter teeth and the roughing cutter teeth provided by the utility model embodiment;

[0016] Figure 4 is a single cutter structure schematic view of a combined petroleum pipe thread cutter provided by the utility model embodiment Figure 1 ;

[0017] Figure 5 is a single cutter structure schematic view of a combined petroleum pipe thread cutter provided by the utility model embodiment Figure 2 ;

[0018] Figure 6 is a cutting distribution schematic view of a combined petroleum pipe thread cutter provided by the utility model embodiment in use;

[0019] The marks in the description drawing include: cutting edge one 1, cutting edge two 2, cutting tooth 3, finishing cutter tooth 4, roughing cutter tooth 5. DETAILED DESCRIPTION

[0020] The following is further explained in detail through specific embodiments:

[0021] The embodiment is basically as shown in the accompanying Figure 3 , Figure 4 and Figure 5 : a combined petroleum pipe thread cutter, including at least one finishing cutter and at least one roughing cutter, wherein the finishing cutter and the roughing cutter are independent blades, and are respectively installed in adjacent different stations in use, and each cutter is installed on a cutter bar, so as to be used in conversion with multiple independent blades.

[0022] The main body structure of the finishing cutter and the roughing cutter is the same, and the parameter size and the coating layer are different.

[0023] As shown in Figure 1 and Figure 3 , the main body structure includes a butterfly-shaped cutter body; an installation hole is arranged in the middle of the cutter body; at most two cutting edges are arranged along the circumferential direction of the cutter body, such as 1-2; at most four cutting teeth 3 are arranged on each cutting edge, such as 2-4, and the cutting teeth 3 include finishing teeth and roughing teeth.

[0024] In the embodiment, the finishing cutter adopts a round thread cutter under the API standard, and the inside cutting circle diameter is 8.8 inches, and the outside cutting circle diameter is 9.375 inches. The butterfly structure is the core, the thread is the standard round thread of 8 teeth per inch, two cutting edges are provided, i.e., cutting edge one 1 and cutting edge two 2, and the cutting teeth 3 are arranged in three, which are composed of one fine cutting tooth and two rough cutting teeth, and are arranged in turn as a first rough cutting tooth, a second rough cutting tooth and a fine cutting tooth.

[0025] The parameter size of the rough turning tool is optimized on the basis of the parameter size of the fine turning tool to form a parameter size difference according to the functional positioning, and the corresponding optimization includes that, compared with the corresponding parameter size of the fine turning tool, the fine tooth circular arc in the rough turning tooth is increased by a first proportion, the rough tooth circular arc is increased by a second proportion, the tooth height of the tooth profile is reduced by a third proportion, the rake angle is reduced by a fourth proportion, and the blade edge rounding arc is increased.

[0026] In the combined tool, the rough turning tool is used for removing most of the excess amount and bearing more impact, and the fine turning tool is used for finishing to ensure accuracy and machining quality. Therefore, compared with the fine turning tool, the rough turning tool is optimized under the condition that the cutting edge and the number of teeth are unchanged, the circular arc in the tooth profile is increased to improve the impact resistance, the tooth height in the tooth profile is reduced to reduce the risk of tool breaking, the negative rake angle is processed under the condition that the tool body is unchanged, the tool tip strength is improved, the blade edge rounding arc is increased to reduce the probability of tool breakage, and the coating is changed to further improve the tool life, so as to realize the application effect of the rough turning tool in the combined tool.

[0027] In the embodiment, the first proportion is 18% to 30%, the second proportion is 50% to 70%, the third proportion is 15% to 25%, the fourth proportion is 20% to 30%, and the blade edge rounding arc is increased from the commonly used R0.35-0.45mm to R0.6-0.7mm. Since the rough turning tool faces a higher machine tool speed and the number of tool walking is twice that of the fine turning tool, most of the excess amount is removed, so a smaller tooth height, a larger tooth profile circular arc and a rounding arc are required than the fine turning tool. The increased and decreased proportion range is adjusted and summarized according to actual application, the range is reasonable, and the beneficial effects of the combined conversion use of the scheme can be realized. If it is out of the range, the tool life may be affected.

[0028] As shown in Figure 2 , it is an API standard 8 teeth per inch round thread tooth profile parameter diagram, and the tooth profile parameter value comparison examples of the rough turning tool and the fine turning tool are shown in Tables 1, 2 and 3, as shown in Figure 3 , it is a size difference between the fine turning tooth 4 and the rough turning tooth 5.

[0029] Table 1: Rough turning tool and fine turning tool tooth profile parameter value comparison example one

[0030] A1 A2 A3 A4 A5 P1 P2 Roughing tool 1.47 1.233 0.947 0.097 0.268 3.175 6.35 Finishing tool 1.753 1.419 1.086 0.098 0.36 3.175 6.35

[0031] Table 2: Rough turning tool and fine turning tool tooth profile parameter value comparison example two

[0032] R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 Roughing tool 0.6 0.57 0.6 0.43 0.33 0.35 0.72 0.64 0.3 0.33 Finishing tool 0.498 0.422 0.498 0.7 0.2 0.2 0.54 0.54 0.2 0.2

[0033] Table 3. Comparison of Tooth Profile Parameters for Roughing and Finishing Tools (Example 3)

[0034] β1 B2 B3 B4 B5 B6 Roughing tool 30° 30° 30° 30° 30° 30° Finishing tool 30° 30° 30° 30° 30° 30°

[0035] like Figure 4 and Figure 5 The image shows the appearance of the main structure of the roughing and finishing cutting tools in this combined tool system. The main structure parameters of the roughing and finishing tools are all the same except for the rake face angle. The dimensions shown in Tables 4 and 5 can be selected.

[0036] Table 4. Rake Face Angle

[0037] β β1 β2 Finishing tool 5°±20′ 10°±20′ Roughing tool 5°±20′ 7°±20′

[0038] Table 5 Main Structure Appearance Parameters and Dimensions

[0039]

[0040]

[0041] The coating differences include that the coating used on roughing tools has higher hardness and wear resistance than the coating used on finishing tools.

[0042] In this embodiment, the finishing tool uses a physical vapor deposition (PVD) TiAlN coating, while the roughing tool uses a chemical vapor deposition (CVD) coating with a film thickness of 8–15 μm. It should be noted that the CVD coating thickness of the roughing tool is reasonable. If the finishing tool used the same coating thickness, it would affect its original dimensions, requiring a margin for adjustment, increasing processing difficulty and cost. However, since the functional positioning dimensions of the roughing tool are relatively unimportant, this factor does not affect it. This coating and thickness design significantly improves the wear resistance of the roughing tool, meeting its functional positioning requirements in combined applications.

[0043] In specific use, the machining environment is set to process 2 7 / 8 inch EU oil pipeline couplings on a Mori Seiki NLX 2500 700 machine tool, using L80-13Cr steel, with a maximum speed of 750 r / min. In the original machining process, the thread was completed in 6 passes with a 2-flute + 3-tooth roughing tool, achieving a depth of 2.8 mm. The new process uses this combined tooling solution, with the roughing and finishing tools installed in two adjacent stations, each occupying a tool holder. The specific machining parameters, such as speed, remain unchanged. The roughing tool completes 90% of the allowance in 4 passes, and the finishing tool completes the final shape in 2 passes. The cutting distribution is as follows: Figure 6 As shown.

[0044] The machining method of this combination tool solution is directly compared with the original single-tool machining method. When machining API EU oil pipes, the average life of roughing and finishing tools can reach more than 300 pieces, while that of a single tool can only reach 200 pieces, which is a significant advantage.

[0045] The combined oil pipe threading tool provided in this embodiment changes the traditional approach of machining with a single tool. By using a combination of tools, at a relatively high spindle speed, the roughing tool bears more impact, while the finishing tool ensures precision and machining quality. The entire combined tool system achieves the effect of "stable roughing and durable finishing," significantly reducing the probability of tool breakage. Although compared to multi-tool machining, the combination of roughing and finishing tools seems to increase the switching time, this solution optimizes the structure of the roughing tool, allowing it to bear most of the allowance, reducing the risk of finishing tool failure, and improving the overall stability and lifespan of the combined tool system. In the long run, it ensures the effective use of a set of tools for an extended period, reducing the number of downtime tool changes, effectively compensating for the time spent switching between roughing and finishing tools, ensuring machining efficiency, and achieving the beneficial effects of improving process stability while ensuring relative machining efficiency and tool life, thus achieving an effective balance between efficiency and lifespan.

[0046] The above descriptions are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are knowledgeable of all existing technologies in that field, and possess the ability to apply conventional experimental methods prior to that date. Therefore, those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in conjunction with their own capabilities. Typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent.

Claims

1. A combined oil pipe threading tool, characterized in that, It includes at least one finishing turning tool and at least one roughing turning tool; the finishing turning tool and the roughing turning tool have the same main structure, but their parameter dimensions and coatings are different; The main structure includes a butterfly-shaped cutter body; a mounting hole is provided in the middle of the cutter body; a maximum of two cutting edges are arranged along the circumference of the cutter body; each cutting edge is provided with a maximum of four cutting teeth; The differences in parameter dimensions include, compared to the corresponding parameter dimensions of the finishing tool, the radius of curvature of the finishing tooth in the cutting teeth of the roughing tool is increased by a first proportion, the radius of curvature of the roughing tooth is increased by a second proportion, the tooth height of the tooth profile is decreased by a third proportion, the rake face angle is decreased by a fourth proportion, and the radius of curvature of the cutting edge is increased. The coating differences include that the coating used on roughing tools has higher hardness and wear resistance than the coating used on finishing tools.

2. The combined oil pipe threading tool according to claim 1, characterized in that, One finishing turning tool and one roughing turning tool are provided.

3. The combined oil pipe threading tool according to claim 1, characterized in that, Two cutting edges and three cutting teeth are provided.

4. A combined oil pipe threading tool according to claim 1, characterized in that, The first proportion is 18% to 30%.

5. A combined oil pipe threading tool according to claim 1, characterized in that, The second proportion is 50% to 70%.

6. A combined oil pipe threading tool according to claim 1, characterized in that, The third proportion is 15% to 25%.

7. A combined oil pipe threading tool according to claim 1, characterized in that, The fourth proportion is 20% to 30%.

8. A combined oil pipe threading tool according to claim 1, characterized in that, The blunting radius of the cutting edge is increased to R0.6~0.7mm.

9. A combined oil pipe threading tool according to claim 1, characterized in that, The finishing turning tool uses a physical vapor deposition (PVD) TiAlN coating; the roughing turning tool uses a chemical vapor deposition (CVD) coating.

10. A combined oil pipe threading tool according to claim 9, characterized in that, The chemical vapor deposition coating used for the roughing tool has a film thickness of 8–15 μm.

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