RU2524472C1 - Preparation of pipe or sheet edges with plating layer for butt welding (versions) - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: this method comprises machining of edges to make the skews over pipe or sheet with 2-3 mm circular transition to plating layer and nose from plating layer in the form of rectangular ledge. Skew of edges over pipe or sheets to nose is broken at angles of 1-2 and 4-8 degrees. Nose from plating layer is 2.5-3.5 mm high and 3.4-4.7 mm long. In compliance with second version, method comprises machining of edges to produce skew with nose over pipe or sheet and bore with skew on plating layer side to depth larger than thickness of the latter. Skew of edges over pipe or sheet to nose features angle of 1-2 degrees. Nose is shaped to rectangular ledge and is 1.8-2.3 mm high and 3.2-5.2 mm long while bore features skew angle of 52-57 degrees.

EFFECT: lower material input, simplified design of welding set, higher quality of weld.

3 cl, 2 dwg

Description

The invention relates to the field of welding, in particular to the field of giving a special profile to individual sections of edges in the manufacture of butt welded joints, and can find application in automatic argon-arc butt welding of pipes and plates of steel equipped with a clad layer.

According to the first embodiment, a method for argon-arc butt welding of a steel pipe with an inner cladding layer using a non-consumable tungsten electrode with a thickness of 1.5-3.5 mm made of stainless chromium-nickel steel is known. A known welding method includes a method for preparing pipe edges by forming a bevel angle of the edges from 15 ° to 27.5 ° along the pipe and dulling from the cladding layer in the form of a rectangular protrusion.

(CN 101362249, B23K 9/095, published 02/11/2009, CN 101633074, B23K 9/23, published 01/27/2010)

The closest in technical essence and the achieved result is a method of preparing pipe edges with a cladding layer of 2 mm thickness for butt welding using a non-consumable tungsten electrode of a steel pipe with an internal cladding layer of 2 mm thickness, including the formation of the bevel angle of the edges of the pipe 8 ° ± 1 ° with a radial transition of 3 mm into the cladding layer and blunting from the cladding layer in the form of a rectangular protrusion 1.8 ± 0.1 mm high.

(CN 102528244, B23K 9/12, B23K 9/167, publ. 04.07.2012)

The disadvantages of the known methods of preparing the edges of pipes and sheets with a cladding layer for welding is the inability to use the obtained edges for single-pass welding through a slotted butt joint, which makes it possible to reduce the volume of welding material, reduce the waste of alloying components, simplify the design of the welding machine and improve the view of the welding zone (control process).

The closest in technical essence and the achieved result of the second embodiment of the butt joint is a butt welding method of 10GN2MFA pearlite alloy steel pipes with a clad layer on the inside of EI-898 austenitic steel used in the construction of nuclear power plants. The welding method includes a method of forming a gap butt joint of welded clad pipes and plates, and the butt joint is machined with a broken bevel of the edges and blunting along the pipe with bevel angles from the outer surface of the pipe 9 ° ± 1 ° and 15 ° ± 1 °, respectively, and boring with bevelled from the side of the cladding layer with a bevel angle of 20 ° ± 2 ° to a depth greater than the thickness of the cladding layer.

(“Properties of the welded joints of the pipeline D _y = 850 mm of the main circulation loop of nuclear power plants performed by automatic welding”, S. A. Belkin, I. V. Ivanova, M. M. Borisenko, V. D., Khodakov, M. M. Petin , Energy Construction, 1992, No. 2, pp. 50-55)

A disadvantage of the known technical solution is that the angle of cutting the edges of the welded joint is too large, which does not allow to fully realize the advantages of slotted cutting.

The objective and technical result of the invention is the creation of methods for preparing the edges of pipes or sheets with a cladding layer for butt welding, which can reduce the amount of welding material when welding the butt, simplify the design of the welding machine, improve the overview of the welding zone while ensuring the quality requirements of the weld metal and the welded joint whole.

The technical result according to the first embodiment is achieved in that the method for preparing the edges of pipes or sheets with a cladding layer for butt welding involves machining the edges to obtain a bevel of the edges in the pipe or sheet with a radius transition to the clad layer, and the radius transition of the edges to the clad layer is 2-3 mm, the blunting from the cladding layer is performed in the form of a rectangular protrusion, and the beveling of the edges along the pipe or sheet to the blunting is done in broken lines with angles of 1-2 ° and 4-8 °, and blunting from the cladding layer in They are 2.5-3.5 mm high and 3.4-4.7 mm long.

The technical result according to the second embodiment is achieved in that the method of preparing the edges of pipes or sheets with a cladding layer for butt welding involves machining the edges to obtain a bevel of the edges, blunting the pipe or sheet, and also boring with a bevel from the side of the cladding layer to a depth greater than the thickness of the cladding layer, and the beveling of the edges along the pipe or sheet to blunting is performed with an angle of 1-2 °, blunting is performed in the form of a rectangular protrusion with a height of 1.8-2.3 mm and a length of 3.2-5.2 mm, and the bore is performed bevel angle 52- 57 °.

The technical result is also achieved by the fact that when the thickness of the cladding layer is 3.8-6.5 mm and the joint gap is 0.01-0.4 mm, the welded joint surfaces are made with a roughness of 3.2 mm.

For welding using butt joints, pipes (Fig. 1) with a wall thickness of 36 and 70 mm and sheets (Fig. 2) with a thickness of 50 mm made of 10GN2MFA steel with a plating coating of 5 mm thick steel EI-898 were used. Butt joints were obtained by machining the welded edges of the pipes 1 and sheets 2, in which the angles 3 of the bevels of the edges along the pipe or sheet and the bore 8, as well as the dimensions of the blunts 4, were the average value of the declared limits. The values of the radius transitions 7 between the elements of the butt joint were 2 mm for the first embodiment of the butt joint and 1-5 mm for the second joint variant, depending on where they were made. The welded surfaces were made with a roughness of 3.2 μm.

The invention can be illustrated by examples of welding pipes and sheets using designs of butt joints obtained by the claimed methods, using fig. 1 and 2, where:

1 - steel pipe or sheet;

2 - cladding layer;

3 - corners of bevels of edges;

4 - dullness;

5 - disclosure of the joint;

6 - clearance;

7 - radius transition;

8 - bevel angle of the bore.

For welding using butt joints, pipes (Fig. 1) with a wall thickness of 36 and 70 mm and sheets (Fig. 2) with a thickness of 50 mm made of 10GN2MFA steel with a plating coating of 5 mm thick steel EI-898 were used. Butt joints were obtained by machining the welded edges of the pipes 1 and sheets 2, in which the angles 3 of the bevels of the edges along the pipe or sheet and the bore 8, as well as the dimensions of the blunts 4, were the average value of the declared limits.

According to the first option, after machining, a radial transition of the edges to the cladding layer of 2-3 mm and blunting from the cladding layer in the form of a rectangular protrusion were obtained, and the edges were slanted along the pipe or sheet to blunt with angles of 1.5 ° and 5 °, and the blunting from the cladding layer is 3.0 mm high and 4.2 mm long.

According to the second option, after machining, the angle of inclination of the edges along the pipe or sheet to blunting was 1.5 °, the blunting had the appearance of a rectangular protrusion 2.0 mm high and 4.2 mm long, and after boring from the cladding layer to a depth greater than the thickness of the cladding layer was obtained oblique at an angle of 55 °.

The values of the radius transitions 7 between the elements of the butt joints amounted to 2 mm for all options. The welded surfaces were made with a roughness of 3.2 μm.

Argon arc welding in one pass was carried out by a standard ADG-UHLL4 automatic machine in a protective gas environment using a welding wire using a non-consumable tungsten electrode with transverse vibrations of the electrode and wire.

For welding butt joints used wire brand Sv-10GS1N1MA, and for the second option to fill the bore - wire Sv-07Kh25N13 and Sv-04Kh20N10G2B.

As a result of welding, welded joints were obtained in which the seams had a dense structure without pores, and the content of the alloying components of the seams provided the required level of service characteristics of the welded joints.

Studies of the mechanical properties of the weld metal of the welded butt joints obtained according to the invention at various temperatures, impact tests and critical brittleness temperatures of the weld metal and welded joints, tests for low and high cycle fatigue showed the correspondence of the obtained welded joints OST 108.300.02-86 .

Claims (4)

1. The method of preparing the edges of the elements with a cladding layer for butt welding, including machining the edges to obtain a bevel of the edges with a radial transition to the cladding layer and dulling from the cladding layer, characterized in that the radius transition of the edges into the cladding layer is 2-3 mm, blunting from the cladding layer is performed in the form of a rectangular protrusion, moreover, the oblique edges to blunting are broken with angles of 1-2 ° and 4-8 °, and blunting from the cladding layer is 2.5-3.5 mm high and 3.4- 4.7 mm. 2. The method according to claim 1, characterized in that when the thickness of the cladding layer is 3.8-6.5 mm and the joint gap is 0.01-0.4 mm, the welded joint surfaces are made with a roughness of 3.2 mm. 3. A method of preparing the edges of elements with a cladding layer for butt welding, including machining the edges to obtain a bevel of the edges and blunting, boring with a bevel from the cladding layer to a greater depth than the thickness of the cladding layer, characterized in that the beveling of the edges to blunting is performed with an angle of 1-2 °, blunting is performed in the form of a rectangular protrusion with a height of 1.8-2.3 mm and a length of 3.2-5.2 mm, and the bevel angle of the bore is 52-57 °. 4. The method according to claim 3, characterized in that when the thickness of the cladding layer is 3.8-6.5 mm and the joint gap is 0.01-0.4 mm, the welded joint surfaces are made with a roughness of 3.2 mm.

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