JPH10139446A - Shear blade for cutting molten glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of a shear blade for cutting molten glass thereby increasing the productivity. SOLUTION: The shear blade for cutting molten glass is formed by laminating the surface of the steel tool blade with the first layer mainly made of titanium nitride 0.1-0.5μm thick, the second layer mainly made of titanium nitride 1.0-5.0μm thick and the third layer mainly made of titanium nitride 1.0-5.0μm thick in turn. In addition, the radius of curvature of the blade edge is adjusted to 0.2-0.25mm to further prolong the blade life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shear blade for cutting molten glass at high speed and accurately in an automatic bottle making line or the like.

[0002]

2. Description of the Related Art At present, automatic bottle making machines with high productivity are introduced for the production of glass containers and the like. Is being formed. A shear blade is used to cut the molten glass supplied to each mold, and the cutting interval is as short as about 0.5 seconds for a small drink bottle or the like having a high molding speed.

A conventional shear blade is a commercially available high-speed tool steel, such as SKH2, which is a JIS symbol, processed into a shape as shown in FIG. 1 and then subjected to a heat treatment. The cutting is performed by sandwiching the molten glass with a blade combined vertically.

[0004] The life of the shear blade varies depending on the composition of the glass, the diameter of the molten glass, and the temperature, but the cutting edge gradually becomes round due to friction with the glass at the time of cutting, and when the limit is exceeded, "burrs" appear on the cut surface of the molten glass. As a result, a defect called a shear mark occurs at the bottom of the molded container. In the production line, the supply of molten glass must be stopped and the shear blade must be replaced before the defect becomes large and the product becomes defective. The mounting position of the shear blade is directly below the glass melting furnace, where the working conditions are poor, and requires fine adjustment such as the contact pressure between the upper blade and the lower blade,
In addition to the adjustment time, the startup adjustment time after replacement is also required. As described above, the replacement of the shear blade has a large effect on the operation rate and production yield,
It has been desired to extend the life of the shear blade.

One of the attempts to extend the life so far is a ceramic shear blade. However, although ceramics have high strength at high temperatures and excellent wear resistance,
Due to low toughness, cracks occur during use, causing blade spills. That is, during the production of non-defective products, defective products suddenly begin to appear, and unlike the high-speed tool steel shear blade, the replacement time cannot be predicted.

The present inventors have already disclosed in JP-A-5-21451.
No. 2 proposes a ceramic-coated member having excellent wear resistance and corrosion resistance using tool steel or the like as a base material and a method of manufacturing the same. Peeled off, and the life was not improved.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a blade for cutting molten glass discharged from a melting furnace in an automatic bin line or the like, and a long-life shear blade excellent in wear resistance at high temperatures. It is intended to provide.

[0008]

According to the present invention, a blade of a shear glass blade for cutting a molten glass is coated with a ceramic film to achieve a long life. In applying the coating to the blade of the shear blade, the present inventors have conducted various studies, and found that there is no abrasion resistance in a high temperature environment, peel resistance under a heat cycle, and no reaction with molten glass, and a long life. And a cutting edge shape having both of the above.

The present invention has the following features. (1) On the surface of the tool steel blade, a first layer mainly composed of Ti nitride and having a thickness of 0.1 to 0.3 μm, and a first layer mainly composed of Ti carbide having a thickness of 1.0 μm. A second layer of ~ 5.0 μm;
Thickness mainly composed of Ti nitride is 1.0 to 5.0 μm
A shearing blade for cutting molten glass, comprising a ceramic film formed by sequentially laminating a third layer with a third layer. (2) The radius of curvature of the cutting edge should be 0.2 to 0.25 in advance.
mm, and then subjected to the film forming process described in (1) above.

Hereinafter, the present invention will be described in detail. Although the life of the shear blade is determined by the wear of the cutting edge, if the hardness is increased to improve the wear resistance, the toughness is sacrificed, and the blade is easily spilled as in the case of the ceramics described in the related art. Therefore, in the present invention, the toughness is maintained by the tool steel as a base material, and the wear resistance is to improve the life by applying a ceramic coating to the surface.

The properties required for the ceramic coating film of the shear blade include that the film does not peel off even under a rapidly quenched use environment, that it has excellent oxidation resistance, and that it does not react with molten glass. Can be The problem of peeling of the film when the adhesion between the ceramic film and the tool steel is poor was solved by selecting a film composition with high adhesion to the tool steel and adjusting the film thickness.

First, in order to ensure sufficient adhesion between the film and the substrate, it is effective to treat the interface between them with a Ti nitride film. This is because if the film contains carbon,
A Ti nitride film was formed on the first layer because of poor adhesion to a steel-based substrate. However, the adhesion in an environment subjected to a rapid thermal quenching thermal cycle is Ti
The thickness of the nitride film is important, and in our tests, it was found that the thickness of the nitride film was 0.1.
If the thickness exceeds 3 μm, the coating is peeled off. If the thickness is less than 0.1 μm, a uniform coating cannot be obtained.
The range was limited to 0.3 μm.

Next, in order to increase the hardness of the entire laminated film, a second layer made of Ti carbide is formed. In this case, if the film thickness is less than 1.0 μm, the life is not improved,
If it exceeds 5.0 μm, the crystal grains become coarse and the impact resistance decreases, so the range is limited to 1.0 to 5.0 μm.

When cutting the molten glass, the cutting edge of the shear blade is exposed to a high temperature for a short time. And T
Since the carbide of i is inferior in high-temperature oxidation resistance and the film is easily worn out, in order to prevent this, as a third layer, a nitride of Ti having excellent oxidation resistance and being chemically stable to molten glass is used. A film was formed. When the film thickness is less than 1.0 μm, the effect is small, and when the film thickness is more than 5.0 μm, the effect is saturated.
The range was limited to 5.0 μm.

Both ceramic films made of Ti carbides and nitrides can be obtained by ion plating using a plasma as a medium and ionizing metal vapor or metal vapor and gas. That is, Ti as a metal evaporation source is melted by an electron gun under a high vacuum of 1 × 10 −3 Torr or less, and this is applied by applying a positive DC bias to an ionization electrode installed above the electron gun evaporation source. It is obtained by being activated in the generated DC plasma. During coating, a negative DC bias is applied to the substrate, and a nitrogen gas or an acetylene gas is introduced as a reactive gas near the substrate.

As a film forming method, other than the above, thermal spraying, CV
Although there are D method and sputtering method, it is difficult to obtain a high-purity dense coating of nitride and carbide by thermal spraying.
In the case of the method D, the crystal grains are coarsened due to the high-temperature film formation, or the shear blade is deformed by heat. In the case of the sputtering method, it is difficult to obtain a thick film with adhesiveness, which is not suitable.

The temperature of the shear blade at the time of film formation must be lower than the normal ion plating processing temperature of 500 ° C. in order to avoid deformation due to thermal strain.
However, in low-temperature film formation, the film adhesion is inferior, so improvement is necessary, and the film can be formed by the following method.

First, the temperature of the tool steel is set to 100 ° C. or more and 400 ° C.
The ion density on the substrate surface is set to 3 A / m ² or more and 5 A or more for 10 seconds or more and 15 minutes or less in the initial stage of film formation.
/ M ² or less, and then adjusted to 1 A / m ² to form a film. Set the temperature of the shear blade to 100 ° C
The reason why the temperature is set to not less than 400 ° C. is that if the temperature is not less than 400 ° C., the hardness of the alloy tool steel as the base material may decrease,
If the temperature is lower than 0 ° C., a hard film having adhesiveness cannot be formed.

The shear blade is, as shown in FIG.
Although the molten glass is cut by sandwiching the upper and lower blades, a sharp blade having an angle of about 30 to 40 degrees is usually attached using a grinder or the like. At this time, the radius of curvature of the cutting edge is less than 0.05 mm, and if this cutting edge is coated with ceramics, it will be as shown in FIG. 3. As can be seen from this figure, the cutting edge which is important when cutting molten glass has rigidity. Since the base portion to be provided is thin, it is easily deformed and the film comes off. Further, the radius of curvature of the cutting edge at which a defect starts to appear on the product due to wear of the cutting edge, that is, the critical radius of curvature for producing a good product was about 0.3 mm.

Therefore, as shown in FIG. 4, the radius of curvature of the cutting edge of the shear blade is previously set to less than 0.3 mm.
The life was further extended by forming a film thereon. Practically, the longest life was obtained when the radius of curvature of the cutting edge was 0.2 to 0.25 mm.

[0021]

EXAMPLES The present invention will be further described below with reference to examples. A 2.3 mm thick JIS standard SKH2 plate was punched out of an alloy tool steel into a predetermined shape by a press, subjected to an oil quenching treatment at 1270 ° C, and a tempering treatment at 550 ° C. The Vickers hardness at this time was 780. Using a grinder, a shear blade provided with a blade in a state normally used was coated with three layers of Ti nitride and carbide from the substrate side using an ion plating apparatus.

The conditions for film formation by ion plating were as follows: Ti was used as a metal evaporation source, which was melted with an electron gun and activated in a DC plasma. The reaction gas used was nitrogen and acetylene. 300V during coating
Was ignited and the pressure was 4 × 10 ⁻⁴ Torr. The surface hardness of the cutting edge was 2400 to 2800 in Hv.

The life comparison between the material of the present invention and the comparative material was performed by attaching the shear blade to an automatic bottle production line at a molten glass temperature of 1180 ° C., a molten glass nozzle diameter of 35 mm, and a cutting speed of 90 times / min. Table 1 shows the life test results.

[0024]

[Table 1]

As can be seen from the results of the life test shown in Table 1, Sample Nos. 1 and 2 within the scope of the present invention show that the number of cuts is 500,000 or more and the life as a shear blade is long. In addition, when the radius of curvature of the blade edge is about 0.22 mm as in sample No. 2, the life is further extended by about 10% than that in sample No. 1.

Sample No. 3 (the first layer thickness is out of the range of the present invention), Sample No. 4 (there is no third layer) and Sample No. 5 (the first to third layers have no coating), which are comparative materials, Also, the number of cuts is about 270,000 to 300,000, and the life as a shear blade is shorter than that of the material of the present invention.

[0027]

According to the present invention, the life of the shear blade for cutting molten glass is remarkably improved, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the appearance of a shear blade.

FIG. 2 is a conceptual diagram of a molten glass cutting operation by a shear blade.

FIG. 3 is a sectional view of a cutting edge portion showing a state where a film is formed on a conventional cutting edge.

FIG. 4 is a cross-sectional view of a cutting edge portion showing a state where a film is formed on the cutting edge of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cutting edge part 2 Upper shear blade 3 Lower shear blade 4 Molten glass 5 Tool steel 6 Coating 7 Cutting edge angle

Claims (2)

[Claims] A first layer having a thickness of 0.1 to 0.3 μm mainly composed of Ti nitride and a thickness of 1.0 μm mainly containing Ti carbide on a tool steel cutting edge surface; A second layer having a thickness of 1.0 to 5.0 μm and a thickness of 1.0 to 5.0 containing a nitride of Ti as a main component.
A shear blade for cutting molten glass, comprising a ceramic film formed by sequentially laminating a third layer having a thickness of μm. 2. The radius of curvature of the cutting edge is set to 0.2 to 0.1 in advance.
A shear blade for cutting molten glass, which is formed by performing the film forming process according to claim 1 after reducing the thickness to 25 mm.