JPH04159003A - Highly efficient cutting method for austenitic high manganese steel - Google Patents

Abstract

PURPOSE:To cut a high Mn steel with high efficiency, by including the carbide, nitride, and carbonitride of Si3N4 whisker, special metal in the specific quantity respectively in a throw away tip, and also forming the whisker from an Al2O3 group ceramics that the whisker is orientated about parallel to the cutting face of the tip. CONSTITUTION:In the case of cutting a high Mn steel, a throw-away tip composed of an Al2O3 group ceramics which includes at 0.5-40wt.% one or two kinds of the carbide, nitride, carbonitride of Si, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W and includes 3-40wt.% Si3N4 whisker, and also with the whisker being orientated about parallel to the cutting face 1 of the tip, used. The tip thus becomes to have a strong resistance force against the cutting main component of force at cutting time. The austenitic high Mn steel can thus be cut with high efficiency with high notch quantity and high sped without causing the tip defect.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a high efficiency cutting method for high manganese steel, and more specifically, a method for cutting high manganese steel and high manganese cast steel, which are difficult-to-cut materials, at high speed and with a large depth of cut. The present invention relates to a method of cutting with an indexable insert (that is, with high efficiency).

(Prior art) High Mn steel and high Mn cast steel (hereinafter referred to as high Mn steel) are materials that are extremely difficult to cut because they have high strength, poor thermal conductivity, and harden during cutting. In other words, it is a difficult-to-cut material.

When performing cutting such as turning or milling on such high Mn steel, in order to cut with relatively high efficiency, it is necessary to use an indexable tip (hereinafter referred to as a tip) that has as high temperature as possible, high hardness, and high strength. required to use.

Although no chips have hitherto been available that can meet these requirements, carbide chips have the highest hardness and strength at high temperatures. Therefore, cutting of high Mn steel is performed using carbide tips. However, even with the method using carbide tips (hereinafter referred to as the conventional carbide tip method), high Mn steel can only be cut at extremely low cutting speeds (less than approximately 30 m/min), resulting in extremely low cutting efficiency. However, there is a problem in that the cutting process takes a long time.

Therefore, in order to solve this problem, various studies have been conducted focusing on ceramics that have high hardness and high strength at high temperatures, and recently a method for cutting high Mn steel using tips made of Al2O3'-T+C ceramics ( Since then, the conventional ceramic chip method) has been developed.

(Problems to be Solved by the Invention) The conventional ceramic chip method described above can cut high Mn steel at a relatively high speed (approximately 30 to 60 m2/m1n). However, there is a problem in that chips often break due to insufficient toughness of the chips. Therefore, there is a problem that cutting is forced with an extremely small depth of cut (less than 1 mm), the cutting efficiency is extremely low, and the cutting process takes a long time.

The present invention has been made with attention to such circumstances, and
The purpose of this method is to solve the above-mentioned problems with the conventional method, and to achieve a higher M than the conventional ceramic chip method.
High Mn that can cut n steel with a high depth of cut without chipping and at an equivalent or higher speed.
The purpose is to provide a highly efficient cutting method for steel. That is, the object of the present invention is to provide a cutting method that can cut high Mn steel with higher efficiency than the conventional carbide tip method and the conventional ceramic tip method.

(Means for Solving the Problems) In order to achieve the above object, the high efficiency cutting method for high manganese steel according to the present invention has the following configuration.

That is, the high-efficiency cutting method according to claim 1 is a method of cutting high-manganese steel with high efficiency at high speed and a high depth of cut using a throw-away tip, wherein the throw-away tip has 5isNi whiskers: 3 to 40 wt. %, and includes Si, Ti, V, Cr, Zr, Nb, M
.

A containing 0.5 to 40 wt% of one or more of carbides, nitrides, and carbonitrides of Hf, Ta, and W, and the whiskers are oriented substantially parallel to the rake surface of the chip.
This is a highly efficient cutting method for high-manganese steel, which is characterized by being made of l2O5-based ceramics.

The high-efficiency cutting method according to claim 2 is characterized in that the whisker is 0.
The high efficiency cutting method for high manganese steel according to claim 1, wherein the amount is 0.3 to 1.5 wt%.

In the highly efficient cutting method according to claim 3, a portion of one or more of the carbides, nitrides, and carbonitrides is A1□0.
3. A highly efficient cutting method for high manganese steel according to claim 1 or 2, wherein the manganese steel is dispersed in nano-order within the crystal grains and exhibits a nanocomposite structure.

The method according to claim 4 is characterized in that the Al2O5-based ceramics or the sintering aids MgO, ZrO2, TiO2,
y2o3, rare earth oxide, Crew, Nip, 5
4. The high-efficiency cutting method for high manganese steel according to claim 1, claim 2, or claim 3, which contains 0.5 to 10.0 wt% of one or more of ift, Cab, Na2O, or chromium carbide. .

(Function) As explained above, the high-efficiency cutting method for high-Mn steel according to the present invention (hereinafter referred to as the present invention method) includes 3 to 40 wt% of S++ J4 whiskers when cutting high-Mn steel. , and si, Ti, V, Cr, Zr, Nb
, Mo, Hf.

Contains 0.5 to 40 wt% of one or more of carbides, nitrides, and carbonitrides of Ta and W (hereinafter referred to as carbides, etc.), and the whiskers are oriented approximately parallel to the rake surface of the chip. An indexable tip (hereinafter referred to as the tip according to the present invention) made of A1.02 ceramics is used.

The chip according to the present invention has <Si3N4> as described above.
It is made of Al2O-based ceramics containing whiskers and carbides. The 513N4 whisker has A1.0. It has the effect of strengthening the matrix and increasing its toughness without causing deterioration of the properties of the base ceramic. Further, carbides etc. have the effect of refining the structure of the matrix, suppressing abnormal grain growth, and increasing the strength. Therefore, the tip according to the present invention is superior in toughness, strength, high-temperature strength, high-temperature hardness, and wear resistance compared to the conventional A120i-TiC ceramic tips and knobs.

Here, the reason why the Si2N4 whisker content is set to 3 to 40 wt% is that if it is less than Swt%, the effect of increasing toughness will be reduced and the fracture resistance will be deteriorated, and if it exceeds 40 wt%, Si3N, which has reactivity with iron. , and the wear resistance deteriorates, and a sufficiently uniform dispersion of whiskers cannot be obtained, resulting in a decrease in strength. Note that the 5lzNt whisker has a needle-like shape.

The reason why the content of carbides, etc. is 0.5 to 40 wt% is that if it is less than 0.5 wt%, the effect of increasing the strength will be reduced, and if it exceeds 40 wt%, the sinterability will decrease, resulting in a dense sintered body. This is because you will not be able to obtain it.

Further, in the chip according to the present invention, the whiskers as described above are oriented substantially parallel to the rake face of the chip. In this way, the axial direction of the acicular 5izN4 whiskers is parallel to the rake face, so the insert has extremely strong resistance to the main cutting force during cutting, and therefore has excellent fracture resistance. It becomes even better. Note that the above-mentioned whisker orientation should be at least within the rake face, that is, in the vicinity of the rake face, which directly affects the cutting performance. Further, as long as such orientation is achieved, the whiskers may be parallel to each other (or perpendicular, radial, or at random).

As described above, the chip according to the present invention has superior toughness, strength, high-temperature strength, high-temperature hardness, wear resistance, and chipping resistance compared to the conventional ceramic chips. If the chip has excellent toughness and chipping resistance, it will be possible to cut high-Mn steel with a high depth of cut, and if the chip has excellent high-temperature hardness, high-temperature strength, and wear resistance, it will be possible to cut high-Mn steel. High-speed cutting is possible. Therefore, compared to the conventional ceramic chip method, the method of the present invention using such chips can cut high Mn steel with a high depth of cut without chipping, and can cut at high speed. Become. That is, quantitatively, cutting speed of high Mn steel: 30m/
Cutting can be performed with a cutting depth of 1 mm or more, and extremely high efficiency cutting is possible.

In order to manufacture a chip according to the present invention, 5isN4 whiskers may be dispersed in a solvent to form a slurry, then mixed with a mixed powder of Al2O3, carbide, etc., sintered, and processed into a chip shape. At this time, if the amount of Sl3N4 whiskers is set to 0.3 to 1.5 wt%, a sufficiently uniform dispersion state of the whiskers can be obtained, and as a result, the strength and toughness of the chip can be further improved, resulting in high strength and high toughness. This is good because it makes it easier to secure. Note that if the amount of 0 is less than 0.3 wt%, the whisker uniform dispersion effect will be small. Compared to the case of 5 wt%, the strength and toughness are lower. Therefore, the amount of ○ of 513N4 whiskers is 0.3~
It is desirable to set it to 1.5 wt%.

When a part of the carbide etc. is nano-dispersed within Al2O and crystal grains to form a nanocomposite structure, S! The combined effect of fiber reinforcement by 3N4 whiskers and nanocomposite reinforcement makes it possible to further improve the strength and fracture resistance of the chip.

Before sintering in the manufacturing process of the chip according to the present invention, MgO, ZrOz, TiO*, Y2(h, rare earth oxide, CrO2, Nip, 5ift, Cab) are used as sintering aids.
, one or more of Na2O or chromium carbide.
．． Addition of 5 to 10.0 wt% improves sinterability, makes the sintered structure finer and more uniform, and makes it easier to ensure high strength and toughness. If the added amount is less than 0.5 wt%, this effect will be extremely small, and if it exceeds 10.0 wt%, the high temperature strength will decrease.

(Example) Example 1 5IJ4 whiskers whose amount was adjusted to 0.6 wt% were added to a solvent, and ultrasonic energy was applied for 30 minutes to uniformly disperse them in the solvent to obtain a slurry. Al2O is added to the slurry.
A mixture containing 2 powders and carbides, or a sintering aid was added, and both were stirred and mixed in a wet mill for 20 hours, and then dried and granulated in a spray dryer. The obtained mixed powder was packed into a graphite mold and heated for 1 hour in an Ar air flow.
Uniaxial pressure sintering was performed using a hot press for 30 minutes under the conditions of 8508C and 200Kg/cm2 to obtain a sintered body (i.e. A
120i-based ceramics) were obtained. In this way, the whiskers in the sintered body can be oriented two-dimensionally parallel to the hot press surface. Furthermore, S1! The amounts of Na whiskers and carbides added, as well as the type and amount of sintering aids, were varied as shown in Table 1. 51iN4 whisker content is 15-30wt
%.

5.2 x 13.5 x 13.5 mm from the above sintered body so that the hot press surface and the rake surface of the chip are parallel.
Cut out a chip and use a chip polisher to grind it into 5NG.
Processed into the shape of N434T-4 (ISO standard).

A front view of this chip is shown in FIG. 1, and a side view is shown in FIG. In these figures, (1) shows the rake face, (2) shows the round corner part, (3) shows the honing part, and (4) shows the honing width. The corner radius of the round corner portion (2) is 1.6 mm, and the honing width (4) is 0.2 mm.

The thus obtained chip is an example of the chip according to the present invention, and satisfies all the conditions for the chip according to the present invention.

The above chips were attached to a cutting tool to make a tool, and the following cutting tests were conducted using these. That is, high Mn steel was used as the work material, the cutting speed was 60 m/min, and the depth of cut was 5 m.
A cutting test was conducted at m, feed amount + 0.25 mm/rev, and the time until breakage was measured. As shown in Table 1, the loss time was 70 to 1)0 minutes.

In addition, for the chip of experiment No. 3 shown in Table 1, depth of cut: 5 mm, cutting time: 30 minutes, cutting speed: 60
We conducted a cutting test on high Mn cast steel under the conditions of m/min or more, feed rate: 0.25 mm/rev or more, and determined the cutting speed limit and feed rate limit that can be cut without chipping. I asked for it. The cutting speed limit value is the feed rate (+, 25
．． 70.50 for 0.355 and 0.5mm/rev
and 35m/min, the limit value of the feed amount is the cutting speed:
60.70 and 0.39 for 100m/min.
0.355 and 0.1 mm/rev.

Example 2 The same tip as in Example 1 was used with a milling cutter (Φ
200.7 teeth) to use as a tool, high Mn steel was used as the work material, and a cutting test was conducted at a cutting speed of 80 m/min, depth of cut: 5 mm, and feed amount: 0.25 mm/1ooth. As shown in Table 1, the missing time is 60~1)0
It was a minute.

Comparative Example 1 By the same method (operation, procedure, conditions) as in Example 1,
A sintered body was obtained. S at this time! Table 2 shows the amounts of J4 whiskers, carbides, etc. added. Note that the amount of 00 in the whisker is 0.6 wt%, which is the same as in Example 1.

Chips with similar dimensions were cut out from the sintered body by the same method as in Example 1. However, in Experiment No. 7, unlike in Example 1, the chips were cut so that the hot press surface and the rake surface of the chip were perpendicular to each other.

The above-mentioned tip was attached to a cutting tool to make a tool, and the same cutting test as in Example 1 was conducted. As shown in Table 2, the loss time was 0.1 to 20 minutes.

Comparative Example 2 Cutting speed similar to Example 1 using a carbide tip: 6
0m/min, depth of cut: 5mm, feed amount: 0.2
5 Table 1 Table 2 (hereinafter referred to as blank space) When a cutting test was conducted on high Mn cast steel under the conditions of mm/rev, crater wear immediately occurred and cutting became impossible.

Also, depth of cut +5mm, cutting time: 30 minutes, cutting speed: 10m/min or more, feed rate: 0.2mm/rev
A cutting test was conducted on high Mn cast steel under the above conditions, and the limit values of cutting speed and feed amount were determined. Cutting speed limit values are 20 and 15 for feed rate, 0.2 and 0.35 mm/rev.
m/min, and the feed rate limit values are 0.355 and 0.350 mm for cutting speeds of 10 and 15 m/min.
/rev.

The results of the above Examples and Comparative Examples show that the method of the present invention can cut high Mn steel at a high depth of cut and at high speed without chipping, compared to the conventional ceramic chip method, and achieves high cutting efficiency. It proves that it is possible.

(Effect of the invention) According to the high-efficiency cutting method for high-Mn steel according to the present invention, compared to the conventional ceramic chip method, high-Mn steel can be cut at a high depth of cut and at a high speed without chipping. Becomes capable of cutting. Therefore, compared to the conventional carbide tip method and the conventional ceramic tip method, high Mn steel can be cut with high efficiency, and as a result, the machining time for high Mn steel can be shortened.

[Brief explanation of drawings]

FIG. 1 is a front view showing the shape of the indexable tip according to the first embodiment, and FIG. 2 is a side view showing the shape of the indexable tip according to the first embodiment. (1) - Rake face (2) - Round corner (3) -
Honing section (4) - Honing width patent applicant Kobe Steel Oriya Co., Ltd. Attorney Akira Kanamaru - Figure 1 Figure 2

Claims (4)

[Claims] (1) A method for cutting high manganese steel at high speed and with high efficiency with a large depth of cut, the indexable tip has Si_3N_4 whiskers: 3 to 4
Contains 0wt% and contains Si, Ti, V, Cr, Zr, N
Containing 0.5 to 40 wt% of one or more of carbides, nitrides, and carbonitrides of b, Mo, Hf, Ta, and W,
A highly efficient cutting method for high manganese steel, characterized in that the whiskers are made of Al_2O_3-based ceramics in which the whiskers are oriented substantially parallel to the rake face of the chip. (2) The high-efficiency cutting method for high manganese steel according to claim 1, wherein the whisker has an O content of 0.3 to 1.5 wt%. (3) A portion of one or more of the carbides, nitrides, and carbonitrides is dispersed in the nano-order within the Al_2O_3 crystal grains to form a nanocomposite structure. High-efficiency cutting method for high-manganese steel. (4) The Al_2O_3-based ceramic contains MgO, ZrO_2, TiO_2, Y_2O_ as a sintering aid.
3, rare earth oxide, CrO_2, NiO, SiO_2,
The high-efficiency cutting method for high manganese steel according to claim 1, claim 2, or claim 3, containing 0.5 to 10.0 wt% of one or more of CaO, Na_2O, or chromium carbide.