JPS6029585B2 - Gas processing method for J-shaped or U-shaped grooves - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas machining method for J-shaped or U-shaped grooves in thick plates.

Conventionally, the general method for processing J-shaped or U-shaped grooves is a combination of gas gouging and straight gas cutting.
(see Fig. 1), its gouging surface is semicircular, and a gas cutting torch is operated diagonally from above to cut the base material in the direction of the cutting line of the semicircle (see Fig. 2a).

However, as the plate thickness increases, it becomes difficult to set the cutting torch, and as shown in Figure 2b, if the cutting line deviates even slightly, the semicircular groove will also be cut off, resulting in a V-shaped groove, making it difficult to overlay by welding. Rework will be required. On the other hand, as shown in FIG. 2c, the cutting line reaches the upper part of the semicircular groove, making it impossible to obtain a J-shaped joint, which tends to cause poor twilling during welding. Furthermore, as shown in Figure 2d, even if the cut is ideally made tangent to the semicircular groove, dross may flow directly into the gouging surface and cause damage, so the cut must be made delicately to prevent this. First, it is extremely difficult to set appropriate cutting conditions no matter how the cutting oxygen jet is adjusted. Furthermore, even though it is a semicircular book, it is not uniform throughout the entire plate, and it is virtually impossible to cut in the tangential direction of the semicircular groove. This invention was made in order to eliminate the above-mentioned drawbacks, and in processing a J-shaped or U-shaped groove using both gas gouging and gas cutting, a part of the bottom curve of a J-shaped or U-shaped joint at the joint end. It is characterized by applying gas gouging in the form of a semi-ellipse with a straight line section. Next, a third embodiment of this invention will be described.
This will be explained based on figures a and b.

A gouging surface 3 is bored at the welding machine mouth of the base material 1 by a gas gouging torch 2.

This gouging surface 3 is semi-elliptical and has a straight portion parallel to the joint end. Thereafter, the gas cutting torch 4 performs gas cutting in an oblique direction toward the straight section. For this reason, the straight part (
The range that can be cut is widened by the shaded area in Fig. 3b, and the permissible cutting accuracy during cutting becomes moderate.
In addition, if the cutting line 5 is placed above the straight part of the gouging surface, dross will not flow directly into the gouging surface 3, and the tip can be easily processed using the same gas cutting conditions as the V-bevel cutting of the secondary joint. (Figure 3a).

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the conventional gas processing method, Figure 2a, b,
Figures c and d are side views showing the conventional processing method, and Figures 3a and 3b are side views showing the processing method of the present invention. 1... Base material, 2... Gouging surface, 5
...... Cutting line. Figure 2 Figure 3

Claims (1)

[Claims] 1 J type or U type that uses gas gouging and gas cutting together
In the processing of a J-shaped or U-shaped groove, a semi-elliptical gas gouging having a straight part is applied to a part of the bottom curve of the J-shaped or U-shaped groove at the joint end.
Gas processing method for shaped grooves.