JP2697092B2 - Corrosion prevention method for grooved flange seal surface - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing corrosion of a grooved flange seal surface.

[Prior art] In order to transport fluid while completely suppressing leakage, a groove-shaped seal is formed on the pipe flange of piping made of stainless steel which is hard to corrode to prevent leakage of internal fluid. Connection has been implemented.

FIG. 2 shows an example of this, in which a ring-shaped seal groove 7 is formed in one of the opposed surfaces 5, 6 of the flanges 1, 2 fixed to the ends of the pipes 3, 4, and A ring-shaped seal protrusion 8 that can fit into the seal groove 7 is formed on the other surface 6, and a sealing material 9 such as a gasket is inserted into the seal groove 7, and the seal protrusion 8 is inserted into the seal groove 7. By tightening the flanges 1 and 2 together with bolts 10 or the like so as to be fitted, the seal material 9 is compressed between the seal groove 7 and the seal projection 8 to perform sealing.

[Problems to be Solved by the Invention] However, in the above-described grooved seal, crevice corrosion of the seal surface is apt to occur, and a problem of fluid leakage due to the corrosion has occurred.

For this purpose, the sealing surface (or the entire flange) formed by the sealing groove 7 and the sealing projection 8 is plated with a corrosion-resistant material. However, since the sealing surface has an uneven shape. Therefore, it is difficult to perform plating with a uniform thickness, and therefore, it is easily peeled off by a tightening force at the time of sealing or the like, so that crevice corrosion also occurs.

Further, a material having excellent corrosion resistance (eg, Ti) cannot be plated.

An object of the present invention is to significantly improve the corrosion resistance of a grooved flange seal surface.

[Means for Solving the Problems] The present invention relates to a method for preventing corrosion of a groove-shaped flange seal surface in which a seal groove formed on an opposite surface of a flange and a seal protrusion are fitted to perform sealing. A ring-shaped powder filling groove is formed at a position facing the seal groove on the other flange provided with the seal groove, and cladding powder is charged into the powder filling groove. Then, the cladding powder is melted by a laser cladding method to form a cladding layer integrally in the powder filling groove, and then the other flange is cut to provide a cladding layer at the end. A method for preventing corrosion of a groove-shaped flange seal surface, characterized by forming a seal projection that can be fitted into the seal groove,
It is related to.

[Operation] In the present invention, a ring-shaped powder filling groove is formed at a position opposite to a seal groove formed on one flange of the other flange, and cladding powder is charged into the powder filling groove. The cladding powder is melted by laser cladding to form a cladding layer, and then the other flange is cut to provide a cladding layer at the end and fit into the seal groove Since the sealing projections are formed, a cladding layer having excellent adhesion can be integrally formed on the end surfaces of the sealing projections, so that crevice corrosion due to the sealing projections can be prevented.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1 (A), 1 (B), and 1 (C) show an example of implementing the method of the present invention, and are opposed to one flange 1 having a seal groove 7 as shown in FIG. The other flange 2 provided as described above, the other flange 2
A ring-shaped powder filling groove 16 having a required depth as shown in FIG. 1 (A) is formed at a position facing the seal groove 7 formed on the one flange 1 on the opposing surface 6 of the powder. The cladding powder 11 having excellent corrosion resistance, such as Ti or Al, is charged into the filling groove 16.

Subsequently, as shown in FIG. 1 (B), the cladding powder 11 is melted by irradiating a laser beam 12 by a laser cladding method to form a cladding layer 14 integrally in the powder filling groove 16.

In the laser cladding method, while rotating the laser beam 12 in the width direction of the powder filling groove 16 by the oscilane mirror 13, the other flange 2 is rotated around the center of the flange 2 continuously. Do.

Thereafter, as shown in FIG. 1 (C), a sealing projection 8 having a cladding layer 14 at an end thereof is fitted to a sealing groove 7 formed in the one flange 1 so as to fit into the other. It is formed on the facing surface 6 of the flange 2 by cutting. In FIGS. 1 (A), 1 (B) and 1 (C), the portions indicated by broken lines indicate the portions to be removed by cutting.

According to the above, by covering the end face of the seal projection 8 with the cladding layer 14 having good corrosion resistance, the seal projection 8 is formed.
Can prevent crevice corrosion.

In addition, the cladding layer 14 provided on the seal projection 8 as described above has excellent adhesion, and can prevent the cladding layer 14 from peeling off from the seal projection 8.

[Effects of the Invention] As described above, according to the method for preventing corrosion of the groove-shaped flange sealing surface of the present invention, ring-shaped powder filling is performed at a position of the other flange facing the seal groove formed on one flange. Forming a groove, charging the cladding powder into the powder filling groove, then melting the cladding powder by a laser cladding method to form a cladding layer, and then cutting the other flange By doing so, the cladding layer is provided at the end and the seal protrusion that can be fitted into the seal groove is formed, so that the cladding layer can be integrally provided on the end face of the seal protrusion, Cladding corrosion can be prevented by the seal projection and the cladding layer provided on the seal projection has excellent adhesion. This has the effect of preventing the problem of peeling and corrosion of the layer.

[Brief description of the drawings]

1 (A), 1 (B) and 1 (C) are sectional views showing an example of the method of the present invention, and FIG. 2 is a sectional view showing an example of a conventional pipe flange portion. 1, 2 are flanges, 5 and 6 are opposing surfaces, 7 is a seal groove, 8 is a seal projection, 11 is a cladding powder, 14 is a cladding layer, and 16 is a powder filling groove.

Claims (1)

(57) [Claims] 1. A method for preventing corrosion of a groove-type flange seal surface, wherein a seal groove formed on an opposite surface of a flange and a seal protrusion are fitted to perform sealing, the seal groove having a seal groove. A ring-shaped powder filling groove is formed at a position facing the seal groove on the other flange opposite to one flange, and the cladding powder is charged into the powder filling groove, and then by a laser cladding method. The cladding powder is melted to form a cladding layer integrally in the powder filling groove, and then the other flange is cut to provide a cladding layer at the end and fit in the seal groove. A method for preventing corrosion of a groove-type flange seal surface, characterized by forming a simple seal projection.