JPS5918475B2 - coated high speed steel - Google Patents

Description

[Detailed description of the invention] The present invention relates to coated high speed steel.

The base material is high-speed steel and WC-based cemented carbide, and the IV
- Group A metals (titanium, zirconium, fernium)
So-called coated chips coated with carbides, nitrides, or carbonitrides (which may contain oxygen) to a thickness of several microns have both the toughness of the base material and the wear resistance of the film. It is widely known that it exhibits better properties as a cutting tool than conventional uncoated high-speed steel and WC-based cemented carbide. An object of the present invention is to provide such a coated high-speed steel with further improved properties.

X-ray diffraction is generally used to analyze the crystal structure of substances, but there is some controversy as to what the half-width of an X-ray diffraction curve means. According to one theory, it is said that it depends on the dislocation density in the sample, and it is said that the wider the width at half maximum, the higher the dislocation density. Therefore, the inventors believe that if the dislocation density in the coating of coated high-speed steel is high, peeling of the coating and damage to the base material due to wear and crack progression that occur in the coating of the cutting edge of the tool during cutting can be suppressed. Thought. It was found that the coated high-speed steel formed according to this idea, which exhibits a half-value width above a certain level, exhibits extremely superior toughness and wear resistance when compared with ordinary coated high-speed steel. . FIG. 1 schematically shows an ion brating apparatus used to produce the coated high-speed steel of the present invention.

In the figure, reference numeral 1 denotes a vacuum chamber, which is evacuated through an exhaust pipe 2. Inside the vacuum chamber 1, there are a substrate 4 to which a negative voltage is applied by a substrate power source 3, an ionization electrode 6 to which a positive voltage is applied by an ionization power source 5, and a reaction gas introduction pipe 7.
and an evaporation source 8 heated by an electron beam. Now, when the electron beam is irradiated to the evaporation source 8 to melt and evaporate it, the metal vapor will be ionized between the ionization electrode 6 and become positive ions, which will head toward the substrate to which a high negative voltage is applied, and will be combined with the reaction gas. While reacting, it adheres to the high-speed steel supported by the substrate, forming a coating.

Note that 2θ is 0. The reason for limiting it to C or higher is that 2θ is 0.4
In the following cases, the wear resistance as a tool is insufficient,
This is because it is not practically effective and exhibits excellent cutting performance when 2θ is 0.4° or more, especially 0.5° or more.

Examples are shown below.

Note that the half-width in the examples is determined by measuring the diffraction curve of Cu-Kα rays using a diffractometer using a copper target and a nickel filter, and determining the height of 1/2 between the background and the peak of this diffraction curve. The width of the diffraction curve in the part of . Figure 2 shows an example of the diffraction curve from the Ti (200) plane of the product of the present invention, and Figure 3 shows a typical diffraction curve of the product of the present invention.
This is an example of a diffraction curve of a C film.

In both Figures 2 and 3, the horizontal axis is the diffraction angle (2θ),
One scale is 0.2.

The vertical axis shows the diffraction intensity and is dimensionless. The half-width of the product of the present invention shown in FIG. 2 is 0.8°, and the half-width of the product manufactured by the general CVD method shown in FIG. 3 is 0.25°.

Example 1 High-speed steel (material SKH4) was processed into model number SNu432, and titanium was heated and evaporated with an electron beam using an ion plating apparatus shown in Fig. 1 at an ionization voltage of +6.
Ionization was carried out at 0 V, a substrate voltage of -1 KV was applied, and the sample was maintained for 2 hours at 4×10 −4 T 0 rr in an acetylene gas atmosphere.

When the resulting chip was cut and examined, it was found that it was coated with 5 μm titanium carbide, and the hardness of the base material was HRC = 65.2, which was almost unchanged. The coating film of this chip (20
0) The diffraction curve of the Cu-Ka line from the plane has a half-width of 2θ
It was 0.6u. As a comparative example, a blank piece of high-speed steel (material SKH4) was processed into model number SNu432, coated with titanium carbide by the usual chemical vapor deposition method, and heat-treated.

When the obtained chips were cut and examined, the hardness of the base material was H.
C=65.5, and the thickness of the titanium carbide film was 5 μm. Further, the diffraction curve of the Cu--Ka line from the (200) plane of the film had a half-width 2θ of 0.2°. Using both the tip of the present invention and the above-mentioned ordinary coated high-speed steel tip, a workpiece (SCM3) with an outer diameter of 20011 was cut at a cutting speed of 4.
When cutting 0m/Minl depth of cut 21 for 40 minutes at a feed rate of 0.3611/Rev, the flank wear of the chip of the present invention was 0.22111, and the crater wear was 0.051! It was hot.

On the other hand, ordinary coated high-speed steel chips have flank wear of 0.401
! 11 crater wear was 0.15 dragons, indicating that the chip of the present invention had even better wear resistance. Example 2 High-speed steel (material SKH9) was processed into model number SNu432, and titanium was heated and evaporated with an electron beam using the ion plating apparatus shown in Fig. 1 at an ionization voltage of +5
Ionize at 0V, apply a substrate voltage of -0.9KV,
It was held for 3 hours at 6×10 −4 T0rr in a nitrogen gas atmosphere.

When the resulting chip was cut and examined, it was found that it was coated with 8μ titanium nitride, and the hardness of the base metal was HBC-64.2, which was almost the same. The coating film of this chip ((2
The diffraction curve of Cu-Kα rays from the 00) plane has a half width of 2
The angle θ was 0.6°. As a comparative example, high-speed steel (
The raw material SKH4) is processed into model number SNu432,
Titanium nitride was coated by conventional chemical vapor deposition and heat treated.

When the obtained chips were cut and examined, the hardness of the base material was H.
B, C=64.6, and the thickness of the titanium nitride film was 8 μm. Further, the diffraction curve of the Cu-Ka line from the (200) plane of the film had a half width 2θ of only 0.2. Using both the chip of the present invention and the conventional coated high-speed steel chip described above, the milling wear resistance of the work material SCM3 was investigated. The cutting conditions were a cutting speed of 30 m/min, a depth of cut of 21'', a feed of 0.169 n/Revl, and a cutting time of 30. As a result, the blank wear of the chip of the present invention was 0.10JE1, whereas the blank wear of the chip of conventional coated high-speed steel was 0.20jE1, indicating that the chip of the present invention has even better wear resistance. Indicated. Example 3 High speed steel SKH4 (hardness HRC65.l) with model number SNU
Table 1 shows the results of the same cutting test as in Example 1. Shown below.

Note that it was impossible to measure the temperature when an accelerating voltage was applied to the substrate due to the mechanism of the measuring device. Sample rot 1, 5, 6 according to the present invention
, 7, 8, 10 are sample rots 2, 3, 4, which do not belong to the present invention.
It can be seen that this shows superior cutting performance compared to No. 9 and No. 11. As shown in the above examples, it was found that the coated high-speed steel of the present invention exhibits excellent wear resistance, but this is not limited to high-speed steel, and is applicable to various types of steel such as carbon steel and alloy steel. The same applies to steel types.

Therefore, the description of the present invention is directed to general steel types. In addition, when coating any material, the coating film (
When the half width of the diffraction curve of the Cu-Ka line from the 200) plane was 0.4° or less at 2θ, no improvement in toughness and wear resistance was observed compared to conventional products. In the above examples, the ion plating method was used, but it is not necessary to use this method as long as the vapor deposition can be performed using high energy particles at a low temperature. It can be implemented even if

It goes without saying that the present invention can also be applied to a device having a coating film having a composition different from that of the embodiments, or to a case where the coating film is multilayered.

According to the present invention, as described above, it is possible to form a coated high-speed steel in which the half-width of the diffraction curve of Cu-Kα rays from the coating film (200) surface is 0.4° or more at 2θ. As a result, we were able to obtain coated high-speed steel that exhibits superior toughness to conventional steels.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an ion brating device, and FIGS. 2 and 3 are graphs showing diffraction curves based on Cu-Ka diagrams. 1... Vacuum chamber, 3... Board power supply, 4.
... Substrate, 5 ... Ionization power supply, 6 ...
... Ionization electrode, 7 ... Reaction gas introduction pipe, 8 ... Evaporation source.

Claims (1)

[Claims] 1. In a high-speed steel whose surface is coated by an ion plating method, the ion plating method is a reactive ion plating method, and the metal element components in the vapor deposited material are Ionization is mainly done by the discharge of the metal element itself, and the partial pressure of the reaction gas is 1 x 10^-^.
It was generated within the range of 4 to 9 × 10^-^4 Torr, and the composition of the coating film was mainly M (Cu, Nv, O
W) z (However, M is a group IV-a metal (titanium, zirconium, hafnium), C, N, and O represent carbon, nitrogen, and oxygen, respectively, and u, v, and w are C, N, and O atoms, respectively. shows the ratio,
and u+v+w=1, u, v, w≧0, and z represents the stoichiometric ratio of the non-metal component to the metal component, and z≦1. ) from the (200) plane of the coating film of B I type solid solution
A coated steel characterized in that the half width of the diffraction curve by u-Kα rays is 0.4° or more at 2θ.