RU182261U1 - Bimetal Pipe Preparation for Superheated Steam Pipelines - Google Patents

Abstract

The utility model relates to the field of pipe production, namely, to the production of bimetallic pipe blanks from heat-resistant steels for the manufacture by welding of superheated steam pipelines, in particular pipe elements of the main circulation circuit of a water-water atomic type reactor. The objective and technical result of the utility model is the procurement of a bimetallic pipe for superheated steam pipelines, which provides increased structural strength of the pipeline at a temperature of superheated steam above 350 ° C and pressure above 17 MPa. The technical result is achieved by the fact that the bimetallic pipe billet for superheated steam pipelines made of heat-resistant steel with an electroslag method deposited on the inner surface by an austenitic steel layer with an inner diameter of 500-1200 mm, a wall thickness of heat-resistant steel 70 ± 3.8 mm, thickness the deposited layer of steel was 4.0-8.0 mm, while from both ends of the pipe the deposited layer was removed at a distance of 80-100 mm from its ends, and welding was performed at the ends of the pipe with bevelled edges to the blunt a width of 0.5-6.5 mm, and the angle of inclination of the edges to the blunting on the inside of the pipe is 20-55 °, and the bevels of the edges on the outside of the pipe are broken with bevel angles of 8-10 ° from the outer surface of the pipe and 44- 46 ° directly to dullness. 1 of FIG.

Description

The utility model relates to the field of pipe production, namely, to the production of bimetallic pipe blanks from heat-resistant steels for the manufacture by welding of superheated steam pipelines, in particular pipe elements of the main circulation circuit of a water-water atomic type reactor.

The closest in technical essence and the achieved technical result is a bimetallic pipe for superheated steam pipelines made of heat-resistant steel coated with an electroslag surfacing method with a single-layer anticorrosive coating of 4.5-6.5 mm thickness from austenitic steel, the pipe has a diameter of 500 -1200 mm, and a wall thickness of heat-resistant steel 65 mm.

(RU 147694, F16L 9/02, published November 20, 2014).

The disadvantages of the known bimetallic pipe is its unpreparedness for subsequent enlargement by welding, namely the lack of cutting at both ends of the pipe, necessary to reduce the complexity of manufacturing by welding of a superheated steam pipeline, in particular, the main circulation pipe for nuclear power plants with a water-water reactor. In addition, the wall thickness of the pipe blank without taking into account the thickness of the deposited coating of 65 mm is insufficient for reliable operation of the superheated steam pipeline when its temperature rises above 350 ° C and pressure exceeds 17 MPa.

The objective and technical result of the utility model is the procurement of a bimetallic pipe for superheated steam pipelines, which provides increased structural strength of the pipeline at a temperature of superheated steam above 350 ° C and pressure above 17 MPa.

The technical result is achieved by the fact that the bimetallic pipe blank for superheated steam pipelines made of heat-resistant steel with an austenitic steel layer deposited on the inner surface by electroslag surfacing is made with an inner diameter of 500-1200 mm, the wall thickness of heat-resistant steel is 70 ± 3.8 mm, the thickness of the deposited steel layer was 4.0-8.0 mm, while from both ends of the pipe the deposited layer was removed at a distance of 80-100 mm from its ends, and welding was performed at the ends of the pipe with bevelled edges to the blunt a width of 0.5-6.5 mm, and the angle of inclination of the edges to the blunting on the inner side of the pipe is 20-55 °, and the bevels of the edges on the outside of the pipe are broken with bevel angles of 8-10 ° from the outer surface of the pipe and 44- 46 ° directly to dullness.

The utility model can be illustrated by an example of cutting for welding one of the ends of the workpiece shown in FIG. 1, where:

1 - pipe made of heat-resistant steel of pearlite class (base metal);

2 - deposited layer of austenitic steel;

3 - blunting cuts;

4 - bevel edges with broken angles on the outside of the pipe;

5 - bevel of the edges from the inside

According to a utility model, a pipe billet designed for superheated steam pipelines with a temperature of over 350 ° C and a pressure of more than 17 MPa, which had an internal diameter of 850 mm, a wall thickness of 70.25 mm and a length of 2000 mm, was made by the standard method of piercing an ingot of heat-resistant pearlitic steel class 10GN2MFA followed by forging.

Then, an anticorrosion coating was applied in one pass to the inner surface of pipe 1 by electroslag surfacing — layer 2 of austenitic steel 6 ± 2 mm thick using a tape electrode of the Sv-02Kh22N11G2B brand.

After that, by machining at both ends of the pipe, the deposited layer was removed at a distance of 80-100 mm from the ends of the pipe and formed the cutting of the edges for welding with bevels to dullness 3, made with a width of 0.5 ÷ 6.5 mm.

In this case, the bevel angle of the edges to blunting from the inside of the pipe was 28 °. The bevels of the edges on the outside of the pipe were formed broken with bevel angles of 8 ° from the outer surface of the pipe and 45 ° directly to blunting.

The obtained bimetallic pipe billet according to a utility model meets the requirements for pipe billets for the manufacture of superheated steam pipelines in the nuclear industry. The workpiece according to the utility model is fully prepared for subsequent assembly and arc welding during enlargement of the nodes of the AEC main circulation pipeline and its installation. At the same time, the characteristics of the workpiece, including the parameters for cutting the ends for welding, provide a dense structure of the weld metal after welding and the absence of a tendency to form hot cracks during subsequent surfacing of the protective coating on the weld zone, which allows the use of the obtained bimetallic pipe blank for manufacturing pipelines superheated steam with enhanced guaranteed strength characteristics for operation at superheated steam temperatures above 350 ° C and overpressure 17 MPa.

Claims (1)

Preparation of a bimetallic pipe for superheated steam pipelines made of heat-resistant steel with an electroslag method deposited on the inner surface by an austenitic steel layer, characterized in that it is made with an internal diameter of 500-1200 mm, the wall thickness of heat-resistant steel is 70 ± 3.8 mm, and the thickness of the deposited steel layer 4.0-8.0 mm, while from both ends of the pipe the deposited layer is removed at a distance of 80-100 mm from its ends, and welding was performed at the ends of the pipe with bevels of edges to a blunting width of 0.5-6, 5 mm, and the bevel angle of the edges to blunting on the inside of the pipe is 20-55 °, and the bevels of the edges on the outside of the pipe are broken with bevel angles of 8-10 ° from the outer surface of the pipe and 44-46 ° directly to the blunting.

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