JPS6228071A - Welding method for narrow gap member - Google Patents

Abstract

PURPOSE:To eliminate the welding defect of a narrow gap member and to form a penetration bead having the leg length in a fixed size by performing the welding by making a groove larger than the leg length of the penetration bead and by filling a heat resistant flux between the groove and rib. CONSTITUTION:The water soluble deformation inhibitor 5 having a groove 5 is provided near a rib 1 on the recessed part (equivalent to narrow gas part) of the lower plate 2 having the rib 1. This groove 4 is sufficiently made larger than the leg length of the penetration bead at welding time. A heat resistant flux 7 is in succession filled between the groove 4 and rib 1 so as to become slightly lower than the upper face of the rib 1. A welding bead 6 is then formed by performing a TIG arc welding after placing the upper plate 3 having a groove 8 near the rib 1 on the rib 1 of the lower plate 2. Thereafter by spraying a water onto the narrow gap part the flux 7 together with the deformation inhibitor 5 are removed and the narrow gap member of high accuracy whose deformation is prevented can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for welding narrow gap members such as compressors and impellers.

[Prior art]

The present applicant has already proposed a method for welding a narrow gap member consisting of a ribbed lower plate and an upper plate as shown in FIG. That is, in this method, an upper plate 3 having a groove near the top of the rib 1 is placed on a lower plate 2 having ribs 1, and the lower plate 2. Upper plate 3
A water-soluble (water-disintegrating) deformation prevention material 5 such as plaster, which has a groove 4 near the side surface of the rib 1, is provided in the gap, and the groove of the upper plate 3 and the rib 1 are welded. According to this method, it is possible to prevent welding deformation with the preventive material 5 and to weld and manufacture a precise narrow gap member.

[Problem that the invention seeks to solve]

However, in the welding method shown in FIG.
If the groove 4 of the welding bead 6 is made to have the same dimension as the leg length of the uranami bead 6', the uranami bead 6I will directly contact the deformation prevention material 5 and a part of the deformation prevention material 5 will melt or deform. Prevention material 5
There is a possibility that welding defects such as cracks and blowholes may occur in the Uranami bead 6' due to the gas generated from the weld.

On the other hand, if the opening width of the groove 4 of the deformation prevention material 5 is made sufficiently larger than the leg length of the uranami bead 6', the welding defect described above will not occur because the uranami bead 6' will not come into direct contact with the deformation prevention material 5. However, due to variations in welding conditions, etc., it becomes difficult to form a uranami bead with a constant leg length.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for welding narrow-gap members that is free from welding defects and can form an uranami bead with a constant leg length.

[Failure to solve the problem]

In welding a narrow-gap member consisting of ribbed plates and plates, the present invention provides a water-soluble deformation prevention material gold film having grooves near the ribs in the narrow gap part, and also makes the line grooves larger than the leg length of the uranami bead. The present invention is characterized in that heat-resistant flux is filled between the groove and the rib to perform welding.

[For production]

In the present invention, by enlarging the grooves of the deformation prevention material, it is possible to avoid direct contact of the Uranami bead with the deformation prevention material.

Furthermore, by making the fluff filled between the groove and the ribs excellent in heat resistance, it hardly melts even when it comes into contact with the Uranami bead, and does not have any adverse effect on the Uranami bead.

Furthermore, the height of the heat-resistant flux controls the Uranami peak r, resulting in a constant leg length.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

First, a deformation preventing material 5 made of disintegrated gypsum and having grooves 4 near the ribs 1 is provided in a recess (corresponding to the narrow gap) of a lower plate 2 made of Cr--Mo steel and having ribs 1 . Note that the groove 4 was made sufficiently larger than the leg length of the uranami bead during welding 1, and then heat-resistant flux 7 was filled between the groove 4 and the rib 1 so that it was 2 m lower than the upper surface of the rib 1. . This flux 7 has a melting point of 1500°C and Mg050.

CaF' 15%, l'-120,10%, C
It consists of a composition of 20% aO and 5in25%. Then,
An upper plate 3 made of Cr-Mo steel having a groove 8 near the rib 1 was placed on the rib 1 of the lower plate 2, and then TIG welding was performed to form a weld bead 6. Incidentally, by spraying water into the narrow gap after welding, the flux 7 was also removed together with the deformation prevention material 5.

When the leg length of the uranami bead 6' after welding was examined, the results shown in the table below were obtained. In addition, in the table, melting point 1
The leg lengths of the Uranami bead when normal welding flux at 050° C. was used and when no slack was used are also shown as Comparative Examples 1 and 2, respectively.

In addition, when the condition of the Uranami bead after welding was examined, no welding defects such as cracks or blowholes were observed.

〔Effect of the invention〕

As described in detail above, according to the welding method of the present invention, welding deformation is prevented by providing a water-soluble deformation preventing material in the narrow gap part, a highly accurate narrow gap member can be manufactured, and the groove of the preventing material is By filling heat-resistant flux between the weld and the rib, it does not adversely affect the welding and has the advantageous effect of forming a smooth Uranami bead with a constant size without welding defects.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing the welding process in an embodiment of the present invention, Fig. 2 is a sectional view of the main part of Fig. 1, and Fig. 3 is a sectional view showing a welding method already proposed by the applicant. be. 1...Rib, 2...Lower plate, 3...Upper plate, 4...
Groove, 5... Deformation prevention material, 6... Welding bead, 6'.
・・Uranami bead, 7・−・Heat resistant flux, 8・・
Bevel.

Claims (1)

[Claims] In welding a narrow gap member consisting of a ribbed plate and a plate, a water-soluble deformation prevention material having a groove near the rib is provided in the narrow gap, and the groove is made larger than the leg length of the uranami bead, and A method for welding narrow gap members, characterized in that welding is performed by filling heat-resistant flux between the ribs.