JPS61126970A - Cutting method of steel plate coated with primer rich in zinc - Google Patents

Abstract

PURPOSE:To obtain a fine cut face of a steel plate coated with zinc-rich primer and improve the efficiency of the cutting work, by blowing compressed air to the vicinity of a cutting nozzle from the back of the cutting nozzle in its advancing direction. CONSTITUTION:A pipeline 6 connected with a compressed air source and supported by a bracket 5 fixed to a cutting torch 2 is put behind the torch. Two air blowing nozzle 8 are fitted to a holding member 7 provided at the lower end of the pipe line 6. The nozzles 8 are oriented toward the vicinity of the cutting location of a steel plate 1 and they are arranged in such a way that the blown air flows 9 from the nozzles 8 can be directed to both sides of cutting oxygen. When gas cutting is performed by advancing the gas-cutting torch 2, the compressed air of the nozzles are blown to the vicinity of the cutting torch 2 from the back of the torch 2. When such a method is applied, the cutting location and tip of a cutting nozzle 3 are cooled and no cutting slag adheres to the cut section. At the same time, the cutting nozzle 3 is prevented from clogging. Therefore, fine cut faces are obtained and, at the same time, the efficiency of the cutting work is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cutting method for gas cutting a steel plate coated with a zinc-rich primer.

(Conventional technology) When a zinc-rich primer-coated steel plate is gas-cut using the conventional method, molten zinc scatters on the surface of the pipe, resulting in a crater. Cutting was often interrupted by sitting.

Therefore, as a countermeasure against this problem, the following methods have been used in the past.

(Remove the primer at the lift cutting line.

tb) Move the crater away from the steel plate to be cut and reduce the cutting speed.

Apply tc+potassium hydrogen fluoride solution.

(Problem to be Solved by the Invention 1) However, all of the above-mentioned conventional methods have the following problems. Namely, (aJ's method has the disadvantage that it takes a lot of effort to remove the primer. If method (b) is carried out, an abacus bead-shaped cutting slag will adhere to the upper edge of the cutting line, which will require extra finishing work to remove it in the subsequent process.Also, method +C) There is a problem in that it takes time and effort to apply the potassium hydrogen fluoride solution, and if the steel plate to be cut is a thick plate, the cut surface becomes rough.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, when gas cutting a zinc-rich primer coated steel plate, compressed air is injected from behind in the advancing direction of the cutting crater. Make sure to spray near the cutting crater.

(Function) As described above, in the present invention, compressed air is injected from behind in the direction of advance of the cutting crater and is blown near the cutting crater, so that the cut portion of the steel plate and the tip of the crater are cooled. As a result, the cutting slag does not adhere to the cut part, and the distance between the crater and the steel plate? There is no need to increase the size, and there is no need to reduce the cutting speed. Further, there is no need to perform additional operations such as removing the primer at the cutting line or applying potassium hydrogen fluoride solution.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In the figure, 1 is the steel plate coated with zinc-rich primer to be cut, 2 is the cutting torch, 8 is the cutting tip at the lower end of the cutting torch 2, and 4 shown in FIG. 2(b) is the cutting point.
The arrow A indicates the direction of movement of the cutting edge 3.

In this embodiment, the first B! 3, a pipe 6 connected to a compressed air supply source (not shown) is placed behind the cutting torch 2 via a bracket 5 fixed to the cutting torch 2, and connected to the lower end of the pipe 6. Two air injection nozzles 8 are protruded from the nozzle holding member 7, and when these /A/8 are directed near the cutting area of the steel plate 1 as shown in FIG. As shown in Figure 2tbl, the air jet 9 from each nozzle 8 is arranged to sandwich the cutting oxygen 4.

Note that 10 is a pressure regulating pulp installed in the middle of the pipe 6.The pressure of the compressed air used is 5 to 7 cm.
It is appropriate that the diameter of the injection hole of the nozzle 8 is approximately 1 mm, and the other specifications for gas cutting may be the same as those for gas cutting of ordinary steel plates.

The construction method of the present invention uses the above-mentioned equipment.
, 3, 5, 6, 7, 8, and 101 are placed on the steel plate 1, gas cutting is carried out by moving them in the direction of the arrow A in Fig. 2 (b), and compressed air is applied from the rear from /z A/8. P is sprayed to the vicinity of the large cutting opening 2.

In this way, the cut part of the steel plate 1 and the tip of the crater 8 are cooled, so that cutting slag does not adhere to the cut part, and there is no need to increase the distance between the crater 3 and the steel plate 1, and the cutting part is not cut. There's no need to slow down.

Also, remove the primer at the cutting line like in the past, or use potassium hydrogen fluoride solution? There is no need to perform extra coating work.

(Effects of the Invention) Since the construction method of the present invention is as described above, the following effects can be obtained.

b) This can be prevented simply by using a simple device to block the crater and compressed air.

(b) Since the crater is cut close to the steel plate (approximately 20 to 30 degrees), it is cut at an appropriate cutting speed.

For this reason, no notches occur on the cut surface, and a high-quality cut surface that is rough or small can be obtained.

The work of removing the slag that adheres to the upper cutting edge can be completely omitted.

2) There is less chance of misfire caused by a single burner, especially when cutting simultaneously with several torches using a planer, the burden on the operator is reduced, allowing him to perform other tasks, and reducing the risk of misfire caused by a misfire. As a result of completely eliminating work (re-cutting, finishing, etc.), the quality of gas cutting is improved and
Work efficiency is significantly improved.

[Brief explanation of drawings]

Figure 1 is a partial elevation view of the gas cutting device used in the method of the present invention, Figure 2 ((1) is a front view of its nozzle holding member,
b) is a plan view thereof.

Claims (1)

[Claims] 1. A method for cutting a steel plate coated with a zinc-rich primer, which is characterized in that when gas cutting a steel plate coated with a zinc-rich primer, compressed air is injected from behind in the advancing direction of the cutting crater and blows it near the cutting crater.