JP2006192541A - Cutting method for pure iron material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting method for a pure iron material capable of extending the lifetime of a tool without impairing the magnetic characteristic. <P>SOLUTION: The cutting tool whose parent material consists of a hard substance such as sintered hard alloy or cermet etc. equipped with a rake angle ranging between 7-42 degrees is provided for cutting the pure iron material having a carbon content no more than 0.01 wt.%, and therewith the cutting is conducted at a cutting speed of 150 m/min or more. These cutting conditions halve the tool wearing amount when pure iron material of hard-to-cut property is to cut and prolong the lifetime of the tool. This allows lessening the tool replacing frequency and leads to a large improving effect in terms of productivity, manufacturing cost, and quality control of the material to be cut. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cutting method of a pure iron material, and specifically, a cutting method capable of improving the tool life when cutting a pure iron material having a carbon content of 0.01% or less. About.

  Pure iron-based materials are excellent in magnetic properties, but have a high load during cutting. Therefore, improvements in productivity, quality control, etc. for parts with complex shapes in recent years are desired. . Conventionally, in pure iron-based materials such as electromagnetic steel sheets, the electromagnetic characteristics are somewhat lowered, but machinability is often improved by containing a very small amount of carbon. However, there has been an increasing demand for improvement in magnetic properties, and as a result, there has been a growing demand for pure iron-based materials that contain almost no carbon and have excellent magnetic properties. For this reason, this pure iron material is also required to satisfy both machinability and magnetic properties.

For pure iron materials, especially electrical steel sheets, machinability can be achieved without impairing magnetic properties by defining components that affect machinability and magnetic properties, or by controlling the form of non-metallic inclusions. An improved electrical steel sheet is disclosed (for example, see Patent Documents 1 and 2).
JP-A-5-331602 ([0005] to [0012]) JP 2000-30992 A ([0011] to [0016])

  Since the pure iron-based material is a kind of difficult-to-cut material, the cutting tool is usually made of a hard material such as cemented carbide, cermet or CBN sintered body. Even when cutting ferrous materials, the tool life is important from the viewpoint of manufacturing cost and quality control. When the tool life is short, the frequency of tool change is high, and the processing cost is inevitably high. In order to obtain a practically satisfactory tool life without degrading magnetic properties when cutting pure iron-based materials, it is not sufficient to improve the properties of the work material itself as disclosed in Patent Documents 1 and 2. Therefore, it is necessary to appropriately select the processing conditions for performing the cutting process.

  Accordingly, an object of the present invention is to provide a cutting method capable of improving the tool life with a pure iron-based material without impairing magnetic properties.

  In order to solve the above problems, the present invention employs the following configuration.

  That is, the pure iron-based material cutting method according to claim 1 is a pure iron-based material that cuts a pure iron-based material having a carbon content of 0.01 wt% or less with a cutting tool using a hard material as a base material. A cutting method is characterized in that the cutting tool has a rake angle in a range of 7 to 42 degrees and a cutting speed of 150 m / min or more.

  The present inventors examined the influence of the tool shape (rake angle) and the cutting speed on the amount of tool wear from the viewpoint of improving the tool life during cutting of pure iron-based materials. The present inventors have found that the amount of tool wear is halved when all the machining conditions are in the above range. The cutting speed is more preferably 200 m / min or more from the viewpoint of further reducing the amount of tool wear.

In the method for cutting pure iron-based material according to claim 2, the hard material is cemented carbide or cermet, and any one of Al ₂ O ₃ , TiN, TiAlN, and TiCN-based coatings on the surface of the hard material. These coatings are characterized by being applied in a single layer or multiple layers.

  For example, by applying the ceramic coating as described above to the tool surface using a hard material as a base material by PVD, in addition to improving wear resistance, the adhesion and retention of chips on the rake face can be suppressed. Since the welding resistance is improved, a good sharpness is maintained for a longer time, and the amount of tool wear is reduced. The thickness of the coating is preferably about 1 to 20 μm.

  According to the present invention, when cutting pure iron-based material, which has a high ductility and is a kind of difficult-to-cut material, the tool rake angle and cutting speed, which are the main cutting conditions, are reduced from the viewpoint of reducing tool wear by half. Since it can be selected appropriately, machinability is improved without impairing other characteristics such as magnetic characteristics, and the tool life is improved. Moreover, it can contribute to reduction of a tool wear amount by cutting on the said appropriate cutting process conditions using the tool which gave the ceramic coating to the surface which used hard materials, such as a cemented carbide alloy and a cermet, as a base material. The tool life is improved by reducing the amount of tool wear by selecting appropriate cutting conditions and cutting tools, so that the frequency of tool replacement is reduced, and in terms of productivity, manufacturing costs, and quality control of work materials. The improvement effect is great.

  Embodiments of the present invention will be described below with reference to the accompanying FIGS.

FIG. 1 schematically shows a tool shape used for turning of a pure iron-based material. The tool 1 is made of a hard material such as cemented carbide or cermet by Al ₂ O by PVD, for example. _3. TiN, TiAlN, TiCN ceramic coating is applied to a single layer or multiple layers, the rake angle α is formed at any angle in the range of 7 degrees to 42 degrees, and the tool holder has a holder inclination angle β. 2 is attached. And the tool holder 2 equipped with the tool 1 is set on a lathe and is a magnetic steel sheet having a carbon content of 0.01 wt% or less at a cutting speed of 150 m / min or more, more preferably 200 m / min or more. Or the like is cut at a normal feed rate, for example, 0.1 mm / rev. Examples will be described below.

  Table 1 shows a round bar with a diameter of 80 mm of a pure iron-based material with C ≦ 0.01%, Si ≦ 0.03%, 0.2% ≦ Mn ≦ 0.3%, with a cutting speed of 200 m / min. In this way, the tools 1 having different rake angles α are mounted on the tool holder 2 and turned respectively, the wear width of the rake face 1a of the tool 1 is measured, and the value obtained by dividing the measured value by the cutting length is the tool wear. The amount was W. The tool 1 is a cemented carbide base material with a single layer of TiN coated at a thickness of 10 μm, the cutting depth is 0.2 mm, the feed rate is 0.1 mm / rev, and the holder inclination angle β is 15 degrees. It was.

  FIG. 2 is a plot of the tool wear amount W by the turning process described above with respect to the rake angle α of the tool 1. The tool wear amount W on the vertical axis is shown as a ratio to the tool wear amount Wmax, where the tool wear amount Wmax is 1 when the rake angle α is 50 degrees and the wear amount is maximum. From FIG. 2, the tool wear amount W is less than half (indicated by b) of the difference (indicated by a) between the tool wear amount Wmax and the tool wear amount Wmin when the rake angle α having the smallest wear amount is 32 degrees. The rake angle α is in the range of 7 to 42 degrees. It can be seen that if the rake angle α is appropriately selected within this range, the amount of tool wear can be halved.

  From Example 1 (FIG. 2), the amount of tool wear W is minimized when the rake angle α is approximately 32 degrees. Therefore, the tool 1 is made of the same material as in Example 1 and has a rake angle α of 32 degrees. Was mounted on the tool holder 2 and the cutting speed was changed as shown in Table 2, the same pure iron material as in Example 1 was turned, and the amount of tool wear was measured as described above. The cutting amount, feed, and holder inclination angle β are the same as in the first embodiment.

  FIG. 3 is a plot of the amount of tool wear W by the above-mentioned turning process against the cutting speed. The tool wear amount W on the vertical axis is shown as a ratio to the tool wear amount Wmax, where 1 is the tool wear amount Wmax when the wear amount is the maximum and the cutting speed is 80 m / min. FIG. 2 shows that the tool wear amount Wmax is less than half of the difference (indicated by a) and indicated by b (b = a / 2) between the tool wear amount Wmin and the cutting speed of 1000 m / min with the smallest wear amount. The cutting speed at which the wear amount is W is in the range of 150 m / min or more. It can be seen that if the cutting speed is appropriately selected within this range, the amount of tool wear can be halved. From FIG. 3, as the cutting speed increases, the tool wear amount W starts to gradually decrease, and the tool wear amount is remarkably reduced at a cutting speed in the range of about 200 mm / min or more, that is, the tool wear amount. It can be seen that the difference between Wmax and Wmin is ¼ (a / 4) or less. In addition, when the cutting speed is around 1000 m / min, there is almost no decrease in the amount of tool wear. When the cutting speed is increased, the tool temperature increases due to an increase in the frictional resistance of the cutting surface or the finish surface decreases. Therefore, the upper limit of the cutting speed is preferably about 2000 m / min.

  The cutting method according to the present invention is not necessarily limited to turning as shown in the first and second embodiments, and can be applied to general cutting.

The present invention can be used in a cutting process in the process of manufacturing various electromagnetic components from a pure iron-based magnetic material.

It is explanatory drawing which showed typically the tool shape used by embodiment of this invention. It is explanatory drawing which shows the relationship between the rake angle and tool wear amount at the time of cutting a pure iron type material. It is explanatory drawing which shows the relationship between the cutting speed at the time of cutting a pure iron type material, and a tool wear amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tool 1a ... Rake face 2 ... Tool holder

Claims (2)

  A pure iron-based material cutting method for cutting a pure iron-based material having a carbon content of 0.01 wt% or less with a cutting tool using a hard material as a base material, wherein the rake angle of the cutting tool is from 7 degrees A method for cutting a pure iron-based material, which is in a range of 42 degrees and has a cutting speed of 150 m / min or more. The hard material is a cemented carbide or cermet, and any one of Al ₂ O ₃ , TiN, TiAlN, and TiCN coatings is applied to the surface of the hard material in a single layer or multiple layers. The cutting method of the pure iron-type material of Claim 1 characterized by these.

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