Turning method for zirconium-vanadium-iron target material

Abstract

The invention relates to a turning method of a zirconium-vanadium-iron target material, which comprises the following steps: (1) the end face of the zirconium-vanadium-iron target material is turned, the end face turning comprises first rough turning and first finish turning which are carried out in sequence, and cutting fluid is adopted for continuous cooling in the end face turning process to obtain a primarily-machined target material; and (2) cylindrical turning is conducted on the primarily-machined target obtained in the step (1), the cylindrical turning comprises second rough turning and second finish turning which are conducted in sequence, cutting fluid is adopted for continuous cooling in the cylindrical turning process, and the machined zirconium-vanadium-iron target is obtained. According to the turning machining method, the risk of spark generation in the turning process can be reduced, and the machining precision and the machining efficiency of the zirconium-vanadium-iron target material are improved.

Description

Technical Field

[0001] This invention relates to the field of target processing technology, and specifically to a turning method for zirconium vanadium iron targets. Background Technology

[0002] Zirconium is a chemically reactive metallic element with high flammability. During machining, zirconium and its alloys exhibit unique physical and chemical properties, posing certain challenges: for example, zirconium produces sparks when rubbed against a file, and bright sparks are generated when the cutting tool contacts the zirconium material during turning, resulting in a high risk factor for machining zirconium. Improper operation can easily lead to fires and other safety accidents, posing risks to production.

[0003] Currently, zirconium vanadium iron sputtering targets are high-performance alloy sputtering targets with high purity, high density, excellent corrosion resistance, and high-temperature resistance, and are widely used in semiconductors, electronic devices, vacuum systems, and other fields. However, zirconium vanadium iron sputtering targets have high hardness and a certain degree of brittleness, which can easily lead to tool wear during turning, resulting in uneven cutting forces and affecting the flatness and dimensional accuracy of the machined surface. Furthermore, the thermal expansion of the material due to cutting heat during machining can also cause dimensional changes.

[0004] For example, CN114986106A discloses a method for processing a sealing groove on the end face of a tantalum sputtering target. The processing method includes the following steps: (1) using a grooving cutter to perform a first cut and then retract the cutter, the depth of the first cut being 1 / 3 to 1 / 2 of the required depth of the sealing groove; (2) moving the grooving cutter to the required width of the sealing groove to perform a second cut and then retract the cutter, the depth of the second cut being the required depth of the sealing groove; (3) moving the grooving cutter to the position of the first cut and then performing a third cut, the total depth of the third cut and the first cut being the required depth of the sealing groove.

[0005] CN114147243A discloses a method for machining diffusion threads on the end face of a nickel-vanadium target for welding. The machining method includes the following steps: performing finishing turning and thread turning sequentially on the end face of the nickel-vanadium target blank for welding; in the finishing turning, the cutting tool is fed towards the center of the end face of the nickel-vanadium target blank along the diameter direction; in the thread turning, the cutting tool is fed towards the edge of the end face of the nickel-vanadium target blank for welding along the diameter direction.

[0006] However, the above methods are not applicable to the processing of zirconium vanadium iron targets. Therefore, controlling the processing technology and processing parameters based on the properties of zirconium vanadium iron targets, so as to avoid safety hazards in the processing process and improve the processing accuracy of the targets, is a technical problem that needs to be solved in this field. Summary of the Invention

[0007] To address the above problems, the present invention aims to provide a turning method for zirconium vanadium iron targets. Compared with the prior art, the turning method provided by the present invention can reduce the risk of sparks generated during the turning process and improve the machining accuracy and efficiency of zirconium vanadium iron targets.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This invention provides a turning method for zirconium vanadium iron sputtering targets, the turning method comprising the following steps:

[0010] (1) The zirconium vanadium iron target material is face-turned, the face-turning includes a first rough turning and a first finish turning in sequence, and the cutting fluid is used for continuous cooling during the face-turning process to obtain the target material after initial processing.

[0011] (2) The target material obtained in step (1) is subjected to external turning, which includes a second rough turning and a second finish turning in sequence. During the external turning process, cutting fluid is used for continuous cooling to obtain the processed zirconium vanadium iron target material.

[0012] The turning process provided by this invention is divided into two stages: rough turning and finish turning, which can effectively improve machining accuracy. During the turning process, cutting fluid is used for continuous cooling, which can effectively reduce the temperature of the tool and the workpiece, avoid spark generation, and improve machining safety.

[0013] Preferably, the end face turning process in step (1) includes: controlling the target to rotate around the central axis, and feeding the cutter head from the outer circle of the target along the diameter direction toward the center.

[0014] Preferably, the cutting tool used for the end face turning in step (1) includes a detachable cutting tool.

[0015] Preferably, the cutting tool used for the end face turning includes a diamond cutting tool.

[0016] Preferably, during the end face turning, the cutting tool is replaced every 1 mm along the thickness direction of the end face.

[0017] In this invention, the cutting tool is replaced every 1 mm along the thickness direction of the end face during the end face turning process, which can avoid the decline in machining quality due to excessive wear of the cutting tool.

[0018] Preferably, the feed rate of the first roughing car in step (1) is 0.05-0.1 mm / r, for example, it can be 0.05 mm / r, 0.06 mm / r, 0.07 mm / r, 0.08 mm / r, 0.09 mm / r or 0.1 mm / r, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the turning amount of the first roughing turn is 0.2-0.35mm, for example, it can be 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm or 0.35mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the rotational speed of the first roughing machine is 100-120 r / min, for example, it can be 100 r / min, 102 r / min, 104 r / min, 106 r / min, 108 r / min, 110 r / min, 112 r / min, 114 r / min, 116 r / min, 118 r / min or 120 r / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0021] Preferably, the feed rate of the first finishing turn in step (1) is 0.05-0.1 mm / r, for example, it can be 0.05 mm / r, 0.06 mm / r, 0.07 mm / r, 0.08 mm / r, 0.09 mm / r or 0.1 mm / r, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] In this invention, by preferably controlling the feed amounts of the first roughing and first finishing machining within a specific range, the product size and appearance can be effectively guaranteed, and the surface roughness can be reduced.

[0023] Preferably, the turning amount of the first finishing turn is 0.1-0.2 mm, for example, it can be 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm or 0.2 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] In this invention, by preferably controlling the turning amount of the first roughing and the first finishing turning within a specific range, the product size and appearance can be effectively guaranteed, and the surface roughness can be reduced.

[0025] Preferably, the rotational speed of the first precision car is 120-140 r / min, for example, it can be 120 r / min, 122 r / min, 124 r / min, 126 r / min, 128 r / min, 130 r / min, 132 r / min, 134 r / min, 136 r / min, 138 r / min or 140 r / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0026] In this invention, by optimally controlling the rotation speeds of the first roughing and first finishing machining, the product dimensions and appearance can be effectively guaranteed, while reducing surface roughness.

[0027] Preferably, the external turning process in step (2) includes: controlling the target to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target to the outer circle of the other end face along the thickness direction of the end face.

[0028] Preferably, the tool used for external turning in step (2) includes a detachable tool.

[0029] Preferably, the cutting tool used for the external turning includes a diamond cutting tool.

[0030] Preferably, the cutting tool is replaced every 5mm along the radial direction during the external turning process.

[0031] Preferably, the feed rate of the second roughing car in step (2) is 0.05-0.1 mm / r, for example, it can be 0.05 mm / r, 0.06 mm / r, 0.07 mm / r, 0.08 mm / r, 0.09 mm / r or 0.1 mm / r, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the turning amount of the second roughing turn is 0.2-0.35mm, for example, it can be 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm or 0.35mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the rotational speed of the second roughing machine is 100-120 r / min, for example, it can be 100 r / min, 102 r / min, 104 r / min, 106 r / min, 108 r / min, 110 r / min, 112 r / min, 114 r / min, 116 r / min, 118 r / min or 120 r / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0034] Preferably, the feed rate of the second finishing turn in step (2) is 0.05-0.1 mm / r, for example, it can be 0.05 mm / r, 0.06 mm / r, 0.07 mm / r, 0.08 mm / r, 0.09 mm / r or 0.1 mm / r, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] In this invention, by preferably controlling the feed rates of the second roughing machine and the second finishing machine within a specific range, the product size and appearance can be effectively guaranteed, and the surface roughness can be reduced.

[0036] Preferably, the turning amount of the second finishing turn is 0.1-0.2 mm, for example, it can be 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm or 0.2 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] In this invention, by preferably controlling the turning amount of the second roughing turn and the second finishing turn within a specific range, the product size and appearance can be effectively guaranteed, and the surface roughness can be reduced.

[0038] Preferably, the rotational speed of the second precision car is 120-140 r / min, for example, it can be 120 r / min, 122 r / min, 124 r / min, 126 r / min, 128 r / min, 130 r / min, 132 r / min, 134 r / min, 136 r / min, 138 r / min or 140 r / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0039] In this invention, by optimally controlling the rotational speeds of the second roughing machine and the second finishing machine, the product dimensions and appearance can be effectively guaranteed, and surface roughness can be reduced.

[0040] Preferably, the machining fluid comprises an aqueous solution of an emulsion.

[0041] Preferably, the volume concentration of the emulsion is 10-20%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the emulsion is Caltex Amex 3380 water-soluble machining fluid.

[0043] As a preferred embodiment of the present invention, the turning method includes the following steps:

[0044] (1) The end face turning of the zirconium vanadium iron target material includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of the target material along the diameter direction to the center. The cutting tool used for the end face turning includes a detachable cutting tool and a diamond cutting tool. The cutting tool is replaced every 1 mm along the thickness direction of the end face.

[0045] The end face turning includes a first rough turning with a feed rate of 0.05-0.1 mm / r, a turning amount of 0.2-0.35 mm, and a rotation speed of 100-120 r / min, followed by a first finish turning with a feed rate of 0.05-0.1 mm / r, a turning amount of 0.1-0.2 mm, and a rotation speed of 120-140 r / min. During the end face turning process, cutting fluid is used for continuous cooling to obtain the target material after initial machining.

[0046] (2) Perform external turning on the target material obtained in step (1) after initial machining. The external turning process includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target material along the thickness direction of the end face to the outer circle of the other end face. The cutter used in the external turning includes a detachable cutter. The insert used in the external turning includes a diamond insert. The insert is replaced every 5mm along the radial direction during the external turning.

[0047] The external cylindrical turning includes a second rough turning with a feed rate of 0.05-0.1 mm / r, a turning amount of 0.2-0.35 mm, and a rotation speed of 100-120 r / min, followed by a second finish turning with a feed rate of 0.05-0.1 mm / r, a turning amount of 0.1-0.2 mm, and a rotation speed of 120-140 r / min. During the external cylindrical turning process, cutting fluid is used for continuous cooling to obtain the machined zirconium vanadium iron target material.

[0048] The machining fluid includes an aqueous solution of an emulsion, the emulsion having a volume concentration of 10-20%, and the emulsion being Caltex Anquad 3380 water-soluble machining fluid.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) In the turning process provided by the present invention, the turning process is divided into two stages: rough turning and finish turning. By controlling the feed rate, turning amount and rotation speed during the turning process, the machining accuracy can be effectively improved. Under optimal conditions, the surface flatness of the zirconium vanadium iron target material reaches below 0.04 mm, and the machining accuracy is below 0.04 mm.

[0051] (2) In the turning process provided by the present invention, the cutting fluid is used for continuous cooling during the turning process, which can effectively reduce the temperature of the tool and the workpiece, avoid the generation of sparks, and improve the safety of the machining. Detailed Implementation

[0052] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0053] Example 1

[0054] This embodiment provides a turning method for zirconium vanadium iron sputtering targets, the turning method comprising the following steps:

[0055] (1) The end face turning of the zirconium vanadium iron target material includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of the target material along the diameter direction to the center. The cutting tool used for the end face turning includes a detachable cutting tool and a diamond cutting tool. The cutting tool is replaced every 1 mm along the thickness direction of the end face.

[0056] The end face turning includes a first rough turning with a feed rate of 0.06 mm / r, a turning amount of 0.3 mm, and a rotation speed of 110 r / min, followed by a first finish turning with a feed rate of 0.06 mm / r, a turning amount of 0.15 mm, and a rotation speed of 130 r / min. During the end face turning process, cutting fluid is used for continuous cooling to obtain the target material after initial machining.

[0057] (2) Perform external turning on the target material obtained in step (1) after initial machining. The external turning process includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target material along the thickness direction of the end face to the outer circle of the other end face. The cutter used in the external turning includes a detachable cutter. The insert used in the external turning includes a diamond insert. The insert is replaced every 5mm along the radial direction during the external turning.

[0058] The external cylindrical turning includes a second rough turning with a feed rate of 0.06 mm / r, a turning depth of 0.3 mm, and a rotation speed of 110 r / min, followed by a second finish turning with a feed rate of 0.06 mm / r, a turning depth of 0.15 mm, and a rotation speed of 130 r / min. During the external cylindrical turning process, cutting fluid is used for continuous cooling to obtain the machined zirconium vanadium iron target material.

[0059] The machining fluid includes an aqueous solution of an emulsion, the emulsion having a volume concentration of 15%, and the emulsion being Caltex Anquad 3380 water-soluble machining fluid.

[0060] Example 2

[0061] This embodiment provides a turning method for zirconium vanadium iron sputtering targets, the turning method comprising the following steps:

[0062] (1) The end face turning of the zirconium vanadium iron target material includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of the target material along the diameter direction to the center. The cutting tool used for the end face turning includes a detachable cutting tool and a diamond cutting tool. The cutting tool is replaced every 1 mm along the thickness direction of the end face.

[0063] The end face turning includes a first rough turning with a feed rate of 0.05 mm / r, a turning amount of 0.35 mm, and a rotation speed of 120 r / min, followed by a first finish turning with a feed rate of 0.05 mm / r, a turning amount of 0.2 mm, and a rotation speed of 140 r / min. During the end face turning process, cutting fluid is used for continuous cooling to obtain the target material after initial machining.

[0064] (2) Perform external turning on the target material obtained in step (1) after initial machining. The external turning process includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target material along the thickness direction of the end face to the outer circle of the other end face. The cutter used in the external turning includes a detachable cutter. The insert used in the external turning includes a diamond insert. The insert is replaced every 5mm along the radial direction during the external turning.

[0065] The external cylindrical turning includes a second rough turning with a feed rate of 0.1 mm / r, a turning depth of 0.2 mm, and a rotation speed of 120 r / min, followed by a second finish turning with a feed rate of 0.05 mm / r, a turning depth of 0.2 mm, and a rotation speed of 120 r / min. During the external cylindrical turning process, cutting fluid is used for continuous cooling to obtain the machined zirconium vanadium iron target material.

[0066] The machining fluid includes an aqueous solution of an emulsion, the emulsion having a volume concentration of 20%, and the emulsion being Caltex Anquad 3380 water-soluble machining fluid.

[0067] Example 3

[0068] This embodiment provides a turning method for zirconium vanadium iron sputtering targets, the turning method comprising the following steps:

[0069] (1) The end face turning of the zirconium vanadium iron target material includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of the target material along the diameter direction to the center. The cutting tool used for the end face turning includes a detachable cutting tool and a diamond cutting tool. The cutting tool is replaced every 1 mm along the thickness direction of the end face.

[0070] The end face turning includes a first rough turning with a feed rate of 0.1 mm / r, a turning amount of 0.2 mm, and a rotation speed of 100 r / min, followed by a first finish turning with a feed rate of 0.1 mm / r, a turning amount of 0.1 mm, and a rotation speed of 120 r / min. During the end face turning process, cutting fluid is used for continuous cooling to obtain the target material after initial machining.

[0071] (2) Perform external turning on the target material obtained in step (1) after initial machining. The external turning process includes: controlling the target material to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target material along the thickness direction of the end face to the outer circle of the other end face. The cutter used in the external turning includes a detachable cutter. The insert used in the external turning includes a diamond insert. The insert is replaced every 5mm along the radial direction during the external turning.

[0072] The external cylindrical turning includes a second rough turning with a feed rate of 0.05 mm / r, a turning amount of 0.35 mm, and a rotation speed of 100 r / min, followed by a second finish turning with a feed rate of 0.1 mm / r, a turning amount of 0.1 mm, and a rotation speed of 140 r / min. During the external cylindrical turning process, cutting fluid is used for continuous cooling to obtain the machined zirconium vanadium iron target material.

[0073] The machining fluid includes an aqueous solution of an emulsion, the emulsion having a volume concentration of 10%, and the emulsion being Caltex Anquad 3380 water-soluble machining fluid.

[0074] Example 4

[0075] This embodiment provides a turning method for zirconium vanadium iron target material. The only difference from Embodiment 1 is that the feed rate of the first roughing turn is 0.04 mm / r.

[0076] Example 5

[0077] This embodiment provides a turning method for zirconium vanadium iron target material. The only difference from Embodiment 1 is that the feed rate of the first roughing turn is 0.12 mm / r.

[0078] Example 6

[0079] This embodiment provides a turning method for zirconium vanadium iron target material, which differs from that of Embodiment 1 only in that the turning amount of the second rough turning is 0.1 mm.

[0080] Example 7

[0081] This embodiment provides a turning method for zirconium vanadium iron target material, which differs from that of Embodiment 1 only in that the turning amount of the second rough turning is 0.5 mm.

[0082] Example 8

[0083] This embodiment provides a turning method for zirconium vanadium iron target material. The only difference from Embodiment 1 is that the rotational speed of the second finishing turn is 90 r / min.

[0084] Example 9

[0085] This embodiment provides a turning method for zirconium vanadium iron target material. The only difference from Embodiment 1 is that the rotational speed of the second finishing turn is 130 r / min.

[0086] The surface quality of the zirconium vanadium iron targets obtained in Examples 1-9 was tested using a surface roughness tester, and the results are shown in Table 1.

[0087] The machining accuracy (absolute value of the difference between the actual size and the design size) of the zirconium vanadium iron targets obtained in Examples 1-9 was tested using a coordinate measuring machine. The results are shown in Table 1. Generally, the maximum tolerance range is required to be ±0.05mm.

[0088] Table 1

[0089] Surface flatness / mm Machining accuracy / mm Example 1 0.04 0.02 Example 2 0.03 0.03 Example 3 0.04 0.04 Example 4 0.06 0.04 Example 5 0.06 0.06 Example 6 0.07 0.03 Example 7 0.08 0.07 Example 8 0.06 0.05 Example 9 0.07 0.08

[0090] The following can be observed from the data in Table 1:

[0091] (1) As can be seen from the data of Examples 1-3, under better conditions, the surface flatness of the zirconium vanadium iron target material reaches less than 0.04 mm and the processing accuracy is less than 0.04 mm.

[0092] (2) As can be seen from the data of Examples 1 and 4-9, the present invention can further reduce the flatness of the product and make the dimensional accuracy higher by optimizing the control of parameters such as feed rate, turning amount and rotation speed.

[0093] In summary, the turning method provided by this invention can reduce the risk of sparks during the turning process and improve the machining accuracy and efficiency of zirconium vanadium iron sputtering targets.

[0094] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for turning zirconium vanadium iron sputtering targets, characterized in that, The turning process includes the following steps: (1) The zirconium vanadium iron target material is face-turned, the face-turning includes a first rough turning and a first finish turning in sequence, and the cutting fluid is used for continuous cooling during the face-turning process to obtain the target material after initial processing. (2) The target material obtained in step (1) is subjected to external turning, which includes a second rough turning and a second finish turning in sequence. During the external turning process, cutting fluid is used for continuous cooling to obtain the processed zirconium vanadium iron target material.

2. The turning method according to claim 1, characterized in that, The end face turning process described in step (1) includes: controlling the target to rotate around the central axis, and feeding the cutter head from the outer circle of the target along the diameter direction towards the center.

3. The turning method according to claim 1 or 2, characterized in that, The cutting tools used in the end face turning in step (1) include detachable cutting tools; Preferably, the cutting tool used for the end face turning includes a diamond cutting tool; Preferably, during the end face turning, the cutting tool is replaced every 1 mm along the thickness direction of the end face.

4. The turning method according to any one of claims 1-3, characterized in that, Step (1) The feed rate of the first roughing car is 0.05-0.1 mm / r; Preferably, the turning amount of the first roughing turn is 0.2-0.35 mm; Preferably, the rotational speed of the first roughing machine is 100-120 r / min.

5. The turning method according to any one of claims 1-4, characterized in that, Step (1) The feed rate of the first precision turning is 0.05-0.1 mm / r; Preferably, the turning amount of the first precision turning is 0.1-0.2 mm; Preferably, the rotational speed of the first precision car is 120-140 r / min.

6. The turning method according to any one of claims 1-5, characterized in that, The external turning process described in step (2) includes: controlling the target to rotate around the central axis, and feeding the cutter head from the outer circle of one end face of the target to the outer circle of the other end face along the thickness direction of the end face.

7. The turning method according to any one of claims 1-6, characterized in that, The cutting tools used in the external turning in step (2) include detachable cutting tools; Preferably, the cutting tool used for the external turning includes a diamond cutting tool; Preferably, the cutting tool is replaced every 5mm along the radial direction during the external turning process.

8. The turning method according to any one of claims 1-7, characterized in that, In step (2), the feed rate of the second roughing car is 0.05-0.1 mm / r; Preferably, the turning amount of the second roughing turn is 0.2-0.35 mm; Preferably, the rotational speed of the second roughing machine is 100-120 r / min.

9. The turning method according to any one of claims 1-8, characterized in that, In step (2), the feed rate of the second precision turning is 0.05-0.1 mm / r; Preferably, the turning amount of the second finishing turn is 0.1-0.2 mm; Preferably, the rotational speed of the second precision car is 120-140 r / min.

10. The turning method according to any one of claims 1-9, characterized in that, The turning fluid includes an aqueous solution of an emulsion; Preferably, the volume concentration of the emulsion is 10-20%; Preferably, the emulsion is Caltex Amex 3380 water-soluble machining fluid.