JPS5964165A - Underwater plasma cutting method - Google Patents

Abstract

PURPOSE:To facilitate proper cutting and increase capacity by jetting high pressure water near the arc end of plasma arc and scattering molten dross from the cut end of a cut object. CONSTITUTION:A plasma torch 2 is moved relatively to an object 1 to be cut immersed in water, and high pressure water 3a is jetted from a high pressure water jetting nozzle 3 near the arc end 4a of plasma arc 4 while cutting the object 1 by the plasma arc 4. Molten dross generated when the object 1 is molten is scattered from the cut end of the object 1. Accordingly the dross does not solidify in bridgelike form under the cut end 1a of the object 1 to be cut as the case formerly used to.

Description

[Detailed description of the invention] This invention relates to an underwater plasma cutting method.

Conventionally, as shown in FIG. 3, while a plasma torch 11 is moved relative to an underwater object 1o (for example, in the direction of arrow B), a plasma arc 12 is used to move an object 1o to be cut.
In the underwater plasma cutting method for cutting 0, molten dross 13 generated when the object to be cut 10 is melted is rapidly cooled by surrounding water, and a fourth
It solidifies in a bridge shape as clearly shown in the figure. Therefore, even if such a plasma arc is used for cutting, it is not possible to separate 1° of the object to be cut, and the cutting ability is inferior to that in the atmosphere.

The present invention has been made in view of the above-mentioned conventional drawbacks, and provides an underwater plasma cutting method that improves cutting ability by preventing dross from solidifying in the shape of a bridge on the underside of the cutting edge of a workpiece. The purpose is to

Embodiments of the invention will be described below with reference to the drawings.

In FIG. 1, l represents an object to be cut, which is located in water.

Reference numeral 2 denotes a plasma torch, which is held by a holding tool (not shown) so as to be movable relative to the object to be cut (for example, in the direction of arrow A). Reference numeral 3 designates a high-pressure water injection nozzle, which is provided so as to inject high-pressure water 3a toward the vicinity of an arc end 4a of a plasma arc 4 for cutting an object 1 to be cut. Also Noz/I
/3 can be inserted into the cutting groove depending on the case.

Therefore, the defsuma torch 2 is moved relative to the submerged object UIJ, and while cutting the object 1 with the plasma arc 4, high-pressure water is injected from the arc end 4B of the plasma arc 4 and the vicinity. High pressure water 3F3.
By spraying the molten dross generated when the object to be cut l is melted, it is possible to scatter the molten dross from the cutting edge 1illa of the object to be cut l, unlike in the conventional method.
1ia Do not harden in a bridge shape on the bottom surface.

In the above embodiment, high pressure water is injected from the high pressure water injection nozzle /L/3 disposed near the plasma torch 2, but as shown in FIG.
High pressure water 5B from the high pressure waterway 5 formed in the plasma torch 2
Even if a high FE water flow FJ5b is formed around the outer periphery of the plasma arc 4 by irradiating Qp', the dross can be blown away by this high pressure water flow layer R'b.
” - Spring has the same effect as the written example.

As explained above, according to the present invention, high-pressure water is splashed from the cut end of the object to be cut near the arc end of the plasma arc during the cutting operation. 7. Since the base does not solidify to form a bridge, proper cutting can be easily performed and the cutting ability can be improved.

[Brief explanation of the drawing]

It is an explanatory diagram of a conventional example. ■...l! ! Cutting object, la...Lvya r-1,2.
...Puonumatozu, 3R1...High pressure water, 4...Plasma arc, 4a,...Arc end.

Claims (1)

[Claims] (1) In an underwater plasma cutting method in which the object to be cut is cut by a plasma arc while moving the plasma relative to the object under water, high-pressure water is injected near the arc end of the plasma arc during the cutting operation. An underwater plasma cutting method characterized in that the molten dross generated when the object to be cut is melted is scattered from the cutting jar of the object to be cut.