JPH0235895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas cutting nozzle for cutting steel plates, especially painted steel plates. This invention relates to a so-called concentric crater in which gas holes are opened continuously or intermittently.

Figure 1 shows the main parts of a well-known concentric crater A. As shown in the figure, the concentric crater A has a cutting oxygen hole 1 in its center and a preheating gas hole 2 around the cutting oxygen hole 1. And preheating gas hole 2
is opened on the circumference of the opening of the cut oxygen hole 1 in the gas ejection surface 3, and the opening method is a ring shape shown in FIG. 2, a star shape shown in FIG. 2, and a star shape shown in FIG. Gear type is known,
They are used depending on the type of preheating gas used. In any case, conventionally, as described above, the opening 2a of the preheating gas hole 2 is connected to the cutting oxygen hole 1.
They are evenly distributed on a circle around the opening 1a. This is to prevent the inflow of air by surrounding the oxygen jet 0 with the preheated gas flow H, thereby maintaining the purity of the cutting oxygen during gas cutting. If the purity of cutting oxygen decreases, the cutting speed will drop significantly or the condition of the cut surface of the steel plate will deteriorate, causing slag to occur at the edges of the cut surface.

By the way, in gas cutting, there are currently two major problems to be solved. One is to reduce the consumption of cutting oxygen and preheating gas from the perspective of energy conservation, and the other is to concentrically gas cut steel sheets whose surfaces are coated with rust-preventing zinc-containing paint called zinc primer. It is to be carried out efficiently in a type crater.

The latter problem can be explained as follows with reference to FIG. That is, the steel plate 4 having the zinc primer 4a on its surface is heated by the heat of the preheating flame 2a of the crater A, the reaction heat of the cutting oxygen 1a, and the Fe of the steel plate 4, and the zinc primer on the surface of the steel plate melts and becomes liquid ( The melting point of zinc is 420°C), and since the cutting oxygen is injected into the molten zinc primer, some of the burnt material (slag) from the zinc primer tends to scatter upward. On the other hand, most of the cutting oxygen flows outward, but since the injected cutting oxygen is entirely surrounded by the preheating gas, a portion of it circulates within the preheating gas wall as shown in the figure. Under such conditions, the slag is pushed upwards and adheres to the gas ejection surface 3 of the crater A, and as a result, the openings of the preheating gas hole and the cutting oxygen hole are immediately clogged, and in practice, the concentric type Craters cannot be used to cut zinc-primed steel sheets. Therefore, conventionally,
In order to cut zinc primer and steel plates, an eccentric type nozzle with a preheating gas nozzle and a cutting oxygen nozzle placed side by side is used, or a torch for zinc primer treatment is provided separately. However, due to the nature of the crater, the eccentric crater has the disadvantage that the opening of the crater must be placed extremely close to the steel plate, making it extremely difficult to adjust the distance between the crater and the steel plate. If used separately, there is naturally a problem that gas consumption will increase significantly.

In order to solve the former problem, the present inventors first considered the mechanism of gas cutting, and found that the preheating gas at the front of the crater (front of the cutting direction) undergoes a combustion reaction with the steel plate (Fe). However, we conducted various experiments based on the idea that the amount of preheated gas at the rear in the direction of fire could be reduced to some extent. It has been found that not only can consumption of cutting oxygen and preheating gas be reduced while maintaining good cutting conditions, but the latter problem can also be solved.

The gist of the present invention is that the preheating gas hole is
Continuously or intermittently open approximately evenly in a symmetrical area extending from the first half in the crater's direction of travel to the left and right parts of the latter half in the crater's travel direction, and open at one place in the center of the latter half in the crater's travel direction, and the area is symmetrical as described above. A concentric type nozzle for gas cutting is characterized in that a non-opening region for slag scattering is formed between the opening of the mold region and the opening of the central portion.

The present invention will be specifically described below with reference to the illustrated embodiments.

FIG. 4 shows the opening of the crater A according to the present invention. Note that the figure shows a gear-shaped crater as an example.

In the figure, 1a is a cut oxygen hole opening in the center of the gas ejection surface 3, and around the opening 1a,
The preheating gas hole opening is in the crater advancing direction X as shown in the figure.
As seen from the figure, there are nine pieces 2a, 2a, . . . in the first half, one piece 2b, 2b' on each side of the second half, and one piece 2c in the center of the latter half, arranged concentrically and symmetrically. In other words, the openings 2b, 2b' and the opening 2c
The area between the two is a non-opening area. As will be described later, this non-opening area functions to allow the scattering of slag, that is, to prevent the generation of slag. Region Y, which includes nine openings 2a, 2a... and a pair of left and right openings 2b, 2b', roughly corresponds to the spread angle of reaction zone B (blacked out area in the figure) where the steel material is melting during gas cutting. are doing. One opening 2c on the other hand
is located opposite to the groove 5 formed in the steel plate during gas cutting. In the figure, C indicates a molten base material, D indicates a re-solidified base material, and E indicates a solidified oxide.

According to the crater having the above configuration, not only the consumption of preheating gas is reduced in response to the reduced number of preheating gas hole openings compared to the conventional crater, but also the consumption of cutting oxygen can be reduced at the same time. and again,
The cutting speed is almost the same as that of the conventional method, and the roughness of the cut surface of the steel plate is very good, and no slag is generated at the edges of the cut surface. Further, even when cutting a steel plate coated with zinc primer, upward scattering of slag is effectively prevented, and the amount of slag adhering to the gas injection surface of the crater is extremely reduced. This is because the preheating gas hole does not open in most of the latter half of the crater in the direction of propagation, that is, a non-opening area for slag scattering is provided between the openings 2b, 2b' and 2c, so the amount of heat input by the preheating gas As a result, the zinc primer is not sufficiently melted, resulting in a so-called steam-baked state, and even if the zinc primer melts, the reflux of cutting oxygen as shown in Figure 3 does not occur, and the cutting oxygen is absorbed into the zinc. The primer and the steel plate are melted, and the molten material, that is, slag, is scattered in the direction of the non-opening area for slag scattering. Therefore,
Slag is less likely to adhere to the gas ejecting surface of the crater, and is less likely to form on the steel plate itself.

One opening 2c of the preheating gas holes has a great influence on the state of the cut surface of the steel plate. This opening 2c
By providing this, air is extremely effectively prevented from being entrained in the cutting oxygen from the rear side in the direction of propagation of the crater, that is, a decrease in the purity of the cutting oxygen is prevented, and a decrease in the energy of the cutting oxygen jet is prevented. In addition, by providing this opening 2c, the top slag N on the steel plate that would otherwise occur if this opening 2c was not provided.
(See FIG. 5) is prevented from rapidly cooling, and the molten slag is blown away by the ejection energy of the preheated gas from the opening 2c. Therefore, the cut steel plate has no upper slag and a good cut surface can be obtained.

In addition, when using the crater according to the present invention,
As with the case shown in Figure 3, it is important to move the crater in a forward tilted position (for example, around 10 degrees).
If the crater is moved in a state perpendicular to the steel plate, the amount of slag deposited on the gas ejection surface of the crater will increase somewhat, and if the crater is moved in a backward tilted position, upper slag will occur on the steel plate.

The above-mentioned effects of the crater according to the present invention were confirmed by the following comparative experimental examples.

In this experiment, as shown in FIGS. 6 to 6, each crater was created by blocking the preheating gas hole opening of a conventional gear type crater in various ways, and the experiment was conducted for each crater.

Figure 6 shows a conventional gear type crater.

Figure 6 shows that three openings each on the left and right in the rear half of the crater in the direction of crater movement in Figure 6 are closed, while two openings on both sides of the center of the latter half and all openings in the front half are left open. It shows the crater.

Figure 6 shows the crater in which four openings on the left and right in the rear half of the crater in the direction of crater movement in Figure 6 are closed, while one opening in the center of the latter half and all openings in the front half are open. It shows.

FIG. 6 shows that one opening on each side on the right and left sides on a line perpendicular to the direction of movement of the crater in FIG. The crater is shown with one opening between the closed openings, two openings corresponding to the center of the rear half, and the other openings in the front half open.

FIG. 6 shows a crater according to the invention.

When a steel plate was actually cut using each of the above craters, the craters shown in Figure 6 and
Compared to the case of the conventional crater shown in the figure, the cutting speed is very slow and it is difficult to put it into practical use.On the other hand, only the crater according to the present invention (FIG. 6) can provide a satisfactory cutting speed.

Comparative measurements of gas consumption between the conventional crater shown in FIG. 6 and the crater of the present invention shown in FIG.
Approximately 25% of preheating gas was saved.

Furthermore, when we observed the state of slag adhesion on the gas ejection surfaces of the conventional crater and the inventive crater, we found that the conventional crater had an extremely large amount of slag deposited and could only cut about 8 m, but with the inventive crater, Even after cutting 25 m, the amount of slag deposited was extremely small.

As is clear from the results of the above experiments, the present invention does not uniformly arrange the preheating gas hole openings on a circle around the cut oxygen hole openings as in the conventional crater, but partially arranges the preheating gas hole openings in the latter half of the crater in the advancing direction. A simple method of closing the pipe, i.e., not opening it, can achieve the desired objectives, such as saving the amount of gas and reducing slag adhesion.

[Brief explanation of drawings]

Figure 1 is a sectional view of the principle circular center type crater, Figure 2 is a plan view of the gas ejection surface showing the types of conventional preheating gas hole openings, and Figure 3 is the state of circulation of cut oxygen in the conventional crater. Explanatory diagram showing 4th
The figure is a plan view of the gas injection surface of the crater according to the present invention, FIG. 6 is a plan view of the gas ejection surface of a modified crater for comparison with the crater of the present invention, and FIG. 6 is a plan view of the gas ejection surface of the crater of the present invention. 1...Cut oxygen hole, 1a...Cut oxygen hole opening, 2...
Preheating gas holes, 2a, 2b, 2b', 2c... Preheating gas hole openings, A... Crater.

Claims (1)

[Scope of Claims] 1. A concentric type crater in which a cutting oxygen hole is opened at the center of the gas ejection surface, and preheating gas holes are opened continuously or intermittently on a circle around the oxygen hole, and the above-mentioned preheating gas The holes are opened continuously or intermittently substantially evenly in a symmetrical area extending from the first half in the crater traveling direction to the left and right parts of the latter half in the crater traveling direction, and open at one place in the center of the latter half in the crater traveling direction, A concentric type crater for gas cutting, characterized in that a non-opening region for slag scattering is formed between the opening of the symmetrical region and the opening of the central portion.