RU2626116C1 - Method of manufacturing steel axisimetric welding structure - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: welded structure contains an end base, a central tubular element in the form of a thin-walled glass and a thin-walled shell with a thickened bottom. A central tubular element is formed from a circle of sheet steel by drawing in several transitions with intermediate recrystallization annealing. Further, it is dispensed to form a terminal thickening. Form the welded edges for welding the base and thin-walled shell. In this case, a thin-walled shell with a thickened bottom is obtained by extruding the bottom part from the cup and stretching with wall thinning for several transitions with intermediate recrystallization annealing, the end part of the shell is calibrated and the welded edge is formed by machining. The end base is made from a tube workpiece, welded to a tubular element and air tested.

EFFECT: high dimensional accuracy and reliability of the welded vessel body are enhanced.

6 cl, 8 dwg, 1 ex

Description

The invention relates to the field of metal forming and welding, and in particular to methods for the manufacture of axisymmetric steel welded vessels for critical purposes, intended for compressed air, liquefied and dissolved gases and used in various economic fields in the manufacture of fire extinguisher bodies, gas cylinders, liquefied gas cylinders for automotive industry, etc.

Such vessels operate in harsh operating conditions at high pressure, including under the action of cyclic loads. Therefore, high demands are placed on the vessels for tightness and strength, and when performing welds, guaranteed quality must be ensured with a penetration of the root of the seam and the strength of the welded joints not less than 0.9 of the strength of the base metal.

An important task in the assembly and welding of the vessel body is to ensure high dimensional accuracy by preventing warping during the welding deformation during the thermal welding cycle and strain hardening of structural elements entering the vessel after stamping operations, as well as high productivity, low manufacturing cost and low weight .

A known method of manufacturing axisymmetric housings (patent RU 2295416 C1), working under pressure. The method includes hardening, tempering, cold plastic deformation by rotational drawing in two passes, low-temperature annealing.

The closest in technical essence and the achieved result is a method of manufacturing a steel complex-combined steel structure according to the invention patent No. 2449870, B23K 31/02, publ. 05/10/2012, BI No. 13, 2013, adopted by the authors for the prototype, in which a welded tubular element is first formed, then a thin-walled shell, end bases, assembly and welding of subassemblies and the entire welded body, final machining and air tightness tests.

The result is a high-quality complex-combined axisymmetric welded structure with a level of strength of welded joints of at least 0.8 from the base metal.

The reasons that impede the achievement of the technical result indicated below when using the known method for manufacturing a steel axisymmetric welded structure adopted by the authors as a prototype include: the high complexity and cost of manufacturing the components of the vessel due to the large number of parts and welds in the subassemblies and, as a result, insufficient rigidity of the structure; high level of residual stresses; decreased operational reliability of the entire vessel body. In addition, there are no non-destructive methods for controlling the quality of welds that allow one to determine the lack of fusion and the continuity of welds, and ensure the strength of welded joints not less than 0.9 of the strength of the base metal.

Thus, the objective of the technical solution adopted for the prototype is to obtain a high-quality complex combined axisymmetric welded structure with a level of strength of welded joints of at least 0.8 from the base metal.

Common features with the method proposed by the authors for the manufacture of complex combined axisymmetric welded structures are: the manufacture of an end base, a central tubular element, a thin-walled shell with the formation of welded edges for a key joint, assembly of subassemblies by means of a key joint, welding of the end base to the tubular element by automatic welding in shielding gas environment with pneumatic leak testing, final assembly-welding of the housing in the fixture AI, machining and pnevmoispytaniya housing for leaks.

In contrast to the prototype, the method proposed by the applicants for manufacturing a steel axisymmetric welded structure containing an end face and a central tubular element, a thin-walled shell, including the formation of welding edges for a lock connection, assembling subassemblies by means of a lock connection, welding to the tubular element of the end base by automatic welding in protective gases with conducting pneumatic tests of the tightness of the weld, assembly-welding of the subassembly with a thin-walled shell in lacquering and final machining with pneumatic testing of the tightness of the welds with internal pressure, characterized in that the central tubular element is made in the form of a thin-walled cup by drawing from a cup without thinning the wall for several transitions with intermediate recrystallization annealing, drawing with thinning of the wall at the last transition to obtain an end thickening, distribution and machining of the thickening with the formation of a welded edge for assembly-welding, then make a thin-walled shell with a thicker squeezing the bottom part out of the circle and drawing it out with a thinning of the wall of the cylindrical part for several transitions with intermediate recrystallization annealing, or assembling-welding the bottom part and cylindrical, then crimping and calibrating the pressed section of the shell according to the inner diameter and machining with cutting the end face for assembly welding, and the end base is made by machining from a pipe billet, then the assembly-welding is sequentially performed in the fixture of the angular locking joint a neutral tubular element with an end base, carry out pneumatic tests, apply protective coatings on the outer surface of the tubular element and the inner surface of the thin-walled shell, assemble and weld the subassembly with a thin-walled shell with a butt weld seam, perform pneumatic testing of the tightness of the welds, X-ray television control of the butt weld and processing.

In special cases, that is, in specific forms of execution, the invention is characterized by the following features:

- the thickness of the mug of a thin-walled glass is set equal to 2.0-2.5 of the thickness of its wall;

- a thin-walled shell is obtained by extruding a thickened bottom part from a circle, crimping and calibrating the squeezed section along the inner diameter of the cylindrical part from the tube stock, then assembling and automatic welding of the cylindrical and bottom parts in an assembly-welding unit;

- the diameter of the welded edges in the locking connection of the glass and the shell is set equal to (0.4-0.6) (D ₁ + D ₂ ), where:

D ₁ (mm) - the outer diameter of the workpiece of the glass before distribution,

D ₂ (mm) is the inner diameter of the shell preform to crimp;

- on the welded edges of the tubular element and a thin-walled shell with a thickened bottom at the junction of the edges, bevel the edges at an angle of 45 °, and when assembling and arc welding the butt joint with a consumable electrode in a protective gas environment in one pass, the device provides a technological gap of 1 mm in junction;

- when applying protective coatings to the outer surface of the tubular element welded to the base and the inner surface of the thin-walled shell with a thickened bottom, the welding site is protected from the presence of a coating of at least 10 mm wide.

It is this that allows us to conclude that there is a causal relationship between the totality of the essential features of the claimed technical solution and the achieved technical result.

These signs, distinctive from the prototype and to which the requested amount of legal protection applies, are sufficient in all cases.

The task of the invention is to ensure dimensional accuracy, manufacturability, structural strength of welded joints not less than 0.9 of the strength of the base metal and the reliability of the entire welded body of the vessel.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method, including the formation of the welding edges for the castle connection, assembling subassemblies by means of the castle connection, welding to the tubular element of the end base by automatic welding in a protective gas environment with pneumatic tests of the tightness of the weld, assembly-welding sub-assemblies with a thin-walled shell in the fixture and final machining with pneumatic tests of the tightness of welds with internal pressure The main feature is that the central tubular element is made in the form of a thin-walled cup by drawing from a cup without thinning the wall in several transitions with intermediate recrystallization annealing, drawing with thinning the wall at the last transition to obtain an end thickening, distribution and mechanical processing of thickening for assembly welding, then make a thin-walled shell with a thickened bottom by extruding the bottom of the circle and drawing with thinning the wall of the cylindrical part for a few transition s with intermediate recrystallization annealing, or assembly-welding of the bottom part and cylindrical, then crimping and calibrating the pressed section of the shell according to the inner diameter and machining with trimming the end for assembly-welding, and the end base is made by machining from a tube stock, then the assembly is performed sequentially - welding in the fixture of the angular locking connection of the central tubular element with the end base, carry out pneumatic tests, apply protective coatings to the outside th surface of the tubular element and the inner surface of the thin-walled shell, assemble and weld the subassembly with a thin-walled shell with a butt weld, carry out pneumatic tests of the tightness of the welds, X-ray television control of the butt weld and final machining.

A new set of operations, as well as the presence of relations between them, allows, in particular, due to:

- performing a central tubular element in the form of a thin-walled cup by drawing it out of a cup without thinning the wall in a few transitions with intermediate recrystallization annealing, to obtain an all-metal billet for further drawing with thinning by a high-performance pressing method;

- hoods with thinning of the wall at the last transition to obtain an end thickening to obtain a workpiece for further press operations, since this type of hood is a hood with a restriction that allows you to get a thin wall and end thickening;

- distribution and machining of thickening to obtain a welded edge for assembly-welding;

- manufacturing a thin-walled shell with a thickened bottom by extruding the bottom of the circle to obtain a workpiece using the high-performance method of pressing the workpiece for further operations of drawing the cylindrical part of the shell;

- hoods with thinning of the wall of the cylindrical part for several transitions with intermediate recrystallization annealing to obtain a blank of the shell for crimping and calibration by high-performance pressing;

- assembly-welding of the bottom and cylindrical to reduce the complexity of manufacturing the shell and increase the utilization of metal;

- crimping and calibrating the crimped section of the shell according to the inner diameter and machining with trimming the end to form an edge for assembly-welding;

- manufacture of the end base by machining from a pipe billet to reduce the complexity of manufacturing and increase the utilization of metal;

- sequential assembly-welding in the fixture of the angular locking connection of the central tubular element with the end base to obtain a welded subassembly to form the inner contour of the welded structure, and subsequent pneumatic tests to ensure the tightness of the inner contour before welding the thin-walled shell;

- applying a protective coating to the outer surface of the tubular element and the inner surface of the thin-walled shell to provide corrosion resistance of the entire structure under operating conditions;

- assembling and welding subassemblies with a thin-walled shell with a butt weld to obtain a welded structure with a level of weld strength not lower than 0.9 of the strength of the base metal;

- pneumatic tests of the tightness of the welds to ensure the tightness and performance of the welded structure;

- X-ray television control quickly and reliably identify internal defects in the weld metal and the heat-affected zone (lack of fusion, pores, cracks and slag inclusions);

- final machining with obtaining threads on the bottom and end faces to ensure the possibility of connecting the structure with mating parts, as well as its connection with the flanges of devices for pneumatic testing.

Signs characterizing the invention in specific forms of execution, allow, in particular, due to:

- the task of the thickness of the cup of a thin-walled cup equal to 2.0-2.5 of the thickness of its wall is to provide an end thickening for assembly-welding, this value is optimal, since with a cup thickness of less than 2.0 wall thickness the required thickness of the welded edge is not provided, and when the thickness of the circle is more than 2.5 the thickness of its wall, the number of drawing operations with thinning increases;

- obtaining a thin-walled shell by extruding a thickened bottom part from a cup, crimping and calibrating a crimped section along the inner diameter of a cylindrical part from a tube stock, assembling and automatic welding of a cylindrical and bottom part in an assembly-welding installation to reduce the manufacturing complexity and increase the metal utilization rate and ensure high quality welded joint;

- the task of the diameter of the welded edges in the locking connection of the glass and shell equal to (0.4-0.6) (D ₁ + D ₂ ), where:

D ₁ (mm) - the outer diameter of the workpiece of the glass before distribution,

D ₂ (mm) is the inner diameter of the shell preform to crimp,

to reduce the number of press operations of distribution and crimping, since when the diameter of the welded edges is less than 0.4 and more than 0.6, the sum of the diameters of the workpieces increases the number of press operations of crimping or distribution;

- performing on the welded edges of the tubular element and a thin-walled shell with a thickened bottom at the junction of the bevel of the edges at an angle of 45 ° and a technological gap of 1 mm at the junction, ensure penetration of the root of the seam and the entire cross section of the welded joint and the strength of the welded joint required by the design documentation;

- protection of weld joints of locking joints from the presence of protective coatings to a width of at least 10 mm to prevent the formation of defects such as gas pores, slags, and fusion of the welded edges in the weld during welding.

Examining the prior art during a patent search on all types of information available in the countries of the former USSR and foreign countries, it was found that the proposed technical solution does not explicitly follow from the prior art, therefore we can conclude that the criterion of "inventive step" .

The essence of the invention lies in the fact that in the method of manufacturing a steel axisymmetric welded structure containing the end base and the central tubular element, a thin-walled shell, including the formation of welding edges for the castle connection, assembling subassemblies by means of the castle connection, welding to the tube element of the butt base by automatic welding in the medium shielding gases with pneumatic testing of the tightness of the weld, assembly-welding of the subassembly with a thin-walled shell in the fixture research and final machining with pneumatic testing of the tightness of welds with internal pressure, in contrast to the prototype, according to the invention, the central tubular element is made in the form of a thin-walled cup by drawing from a cup without thinning the wall for several transitions with intermediate recrystallization annealing, drawing with thinning the wall at the last transition from receiving end thickening, distribution and machining of thickening for assembly-welding, then make a thin-walled shell with a thickened bottom by pressing the bottom of the circle and drawing with thinning the wall of the cylindrical part for several transitions with intermediate recrystallization annealing, or by assembling-welding the bottom part and the cylindrical, then crimping and calibrating the pressed section of the shell according to the inner diameter and machining with cutting of the end face for assembly-welding, and the end base is made by machining from a pipe billet, then the assembly-welding is sequentially performed in the fixture of the angular castle joint of the central a tubular element with an end base, carry out pneumatic tests, apply protective coatings on the outer surface of the tubular element and the inner surface of the thin-walled shell, assemble and weld the subassembly with a thin-walled shell with a butt lock seam, perform pneumatic testing of the tightness of the welds, X-ray television inspection of the butt weld and final mechanical processing .

The invention is illustrated by drawings, where in FIG. 1 shows the manufacturing process of the central tubular element in the form of a thin-walled cup 1, obtained from the circle “a” by a hood without thinning the wall for 4 transitions: “b”, “c”, “d” and “e” and a hood with thinning the wall with t ₀ (mm) to t ₁ (mm) at the last transition “f” to obtain an end thickening with a thickness of t _ut and a length of l _ut (mm), then by distributing and machining the thickening with the formation of a welded edge with lengths l _st (mm), l _ut ( mm) and thickness t _ut (mm), t ₁ (mm) and the diameter D ₃ (mm), D ₁ (mm) - outer diameter before dispensing cup, D ₃ (mm) - diameter welded after the second dispensing edge and machining.

In FIG. 2 shows the manufacturing process of a thin-walled shell 2 with a thickened bottom obtained from a circle “a” with a diameter of D ₀ (mm), a thickness of t ₀ (mm) by extrusion in 2 transitions “b” and “c”, and three hoods with thinning “d” , "E" and "f", then crimping and calibrating the crimped section "g" according to the inner diameter of the thin-walled part to obtain wall thickness t ₂ (mm) of the inner diameter D ₂ (mm), the outer diameter D ₂ '(mm) and mechanical machining with trimming the end with the formation of a welded edge with a length l _s (mm) and a diameter of D ₃ (mm) for assembly-welding.

In FIG. 2, view A shows a bevelled edge at an angle of 45 ° and a blunted edge of 1 mm.

In FIG. 3 shows the manufacturing process of a thin-walled shell 2 by assembly-welding of the cylindrical part “b” and the bottom part “a”.

The cylindrical part is obtained from the tube billet by crimping and calibrating the crimped section along the inner diameter from one end to obtain a welded edge of length l _b (mm) and diameter D ₃ (mm) and, then, from the other end to obtain a welded edge l _b (mm) and diameter D ₄ (mm).

FIG. 3, view A shows a bevelled edge at an angle of 45 ° and a blunted edge of 1 mm.

FIG. 3, view B shows the welded joint of a thin-walled and thickened bottom of the shell, bevel edges at an angle of 45 ° and a blunt edge of 1 mm in size, the technological gap at the joint of the edges is 1 mm.

In FIG. 4 shows a welded subassembly of the central tubular element — a thin-walled cup 1 with an end base 3 welded to it.

In FIG. 5, view A from FIG. 4 shows the structural elements of the welded corner lock connection of the glass 1 and the base 3, 3 mm - width and 3 mm - the height of the seam.

FIG. 6, view B of FIG. 4 shows the bevel of the edge at an angle of 45 ° and the blunting of the edge of 1 mm.

In FIG. 7 shows a steel axisymmetric welded structure with a central tubular element - a thin-walled cup 1, an end base 3 and a thin-walled shell 2 with a thickened bottom in a welded state.

D ₃ (mm) - the diameter of the welded edges,

D ₁ (mm) - the outer diameter of the glass before distribution,

D ₂ (mm) is the inner diameter of the shell to crimp,

t ₁ (mm) is the thickness of the wall of the glass,

t ₂ (mm) is the wall thickness of the shell.

In FIG. 8, view A from FIG. 7 shows a butt welded joint of a subassembly (base 3 with a glass 1) and a shell 2 with structural elements and a technological gap of 1 mm at the edge joint.

3 mm (max) - the height of the seam.

5 mm (min) - the width of the seam.

The above method of manufacturing a steel axisymmetric welded structure is as follows.

The central tubular element in the form of a thin-walled cup 1 (Fig. 1) is made by extracting from a steel cup “a” with a diameter of D ₀ (mm), a thickness of t ₀ (mm) for six transitions b, c, d, e, f, g with an intermediate recrystallization annealing. Five transitions b, c, d, e, f are performed without thinning the wall. The last sixth transition (g) - with the thinning of the wall from t ₀ (mm) to t ₁ (mm), while using a circle with t ₀ = (2.0-2.5) t ₁ , where t ₁ is the thickness of the finished wall cups. At the last transition, an end thickening is obtained with a length of l _ut (mm) and a thickness of t ₀ (mm), which remains at all six transitions.

Then, the end part of the glass is distributed to a diameter D ₃ (mm) and a thickening is machined to form a welded edge for assembly-welding with dimensions t _ut (mm), l _ut (mm), l _st (mm) and D ₃ (mm) .

Thin-walled shell 2 (Fig. 2) is made of a steel circle "a" with a diameter of D ₀ (mm) and a thickness of t ₀ (mm) by extrusion of the thickened part in two transitions b and c, with intermediate recrystallization annealing. Get a thickened bottom with a diameter of D ₀ (mm) and an inner diameter of the shell D ₂ (mm) and a convex-concave profile of the inner surface. Then the hood is drawn with thinning the wall of the cylindrical part of the shell in three transitions (d, e, f) with intermediate recrystallization annealing to obtain the outer diameter D ₂ '(mm) and the final wall thickness t ₂ (mm).

After that, crimping and calibrating the pressed portion of the shell according to the inner diameter and machining with trimming the end face to the length l _sv (mm) for assembly-welding are performed with the formation of a welded edge with an inner diameter D ₃ (mm) and length l _sv (mm), bevel 45 ° and edge blunting 1 mm.

Alternatively, a thin-walled shell 2 (Fig. 3) is made by assembly-welding of a thin-walled part and a thickened bottom obtained by extrusion from a circle with a diameter of D ₀ (mm) and a thickness of t ₀ (mm).

The thin-walled part is obtained from a tube billet with an outer diameter D ₂ ′ (mm) crimped and calibrated to the crimped section along the inner diameter along one of the ends to obtain an inner diameter D ₃ (mm). After machining the end face, a welded edge is obtained with a length of l _sv (mm), a thickness of t ₂ (mm), a bevel of 45 ° and a blunting of the edge of 1 mm (Fig. 3, view A).

Then the second end is crimped and calibrated according to the internal diameter, the second end is turned, and a welded edge for assembly-welding with a thickened bottom is obtained with dimensions: D ₄ (mm) - inner diameter, l _st (mm) - length of the welded edge, t ₂ (mm) - edge thickness, bevel 45 ° and edge blunting of 1 mm (Fig. 3, view B).

They perform machining with the formation of a butt edge of a thickened bottom with a bevel of 45 ° and a dull edge of 1 mm in size and then assembly and automatic welding of the cylindrical and bottom part of the shell (Fig. 3, view B) in the fixture on the assembly-welding unit, ensuring technological clearance 1 mm.

Thin-walled cup 1 and thin-walled shell 2 (Fig. 1, Fig. 2, Fig. 3 and Fig. 7) with a thickened bottom, prepared for further assembly-welding, are made with the diameter of the welded edges D ₃ (mm)

D ₃ (mm) = (0.4-0.6) (D ₁ + D ₂ ), where

D ₁ (mm) - the outer diameter of the workpiece 1 glass before distribution,

D ₂ (mm) - the inner diameter of the blanks of the shell 2 to crimp.

The end base 3 (Fig. 4) is made by machining from a steel pipe billet. A weldable edge of length l _sv '(mm) is obtained.

Then the assembly-welding of the subassembly in the fixture of the angular locking joint of the central tubular element — the thin-walled cup 1 with the end base 3 — is performed sequentially (Fig. 4, Fig. 5, view A from Fig. 4). On the welded edges of the tubular element - cup 1 (Fig. 6, view B from Fig. 4), at the junction of the edges, the bevels of the edges are angled at an angle of 45 ° and the edge becomes dull with a size of 1 mm Perform pneumatic tests on the installation of pneumatic tests. Protective coatings B (Fig. 4) and D (Fig. 2 and Fig. 3) are applied to the outer surface of the tubular element of the thin-walled cup 1 and the inner surface of the thin-walled shell 2.

When applying protective coatings to the outer surface B of the tubular element-cup 1, welded with a base (Fig. 4) and the inner surface of a thin-walled shell 2 with a thickened bottom (Fig. 2 and Fig. 3), the welding site is protected from the presence of a coating of width l _St. not less than 10 mm.

Then carry out the assembly-welding of the previously welded subassembly with a thin-walled shell with a butt lock seam (Fig. 7, Fig. 8, view A from Fig. 7).

When assembling and arc welding a butt joint with a consumable electrode in a shielding gas atmosphere in one pass, the fixture provides a technological gap of 1 mm at the junction (Fig. 8). Pneumatic testing of the tightness of the welds, x-ray television inspection of the butt welded joint and the final machining of the ends and threaded holes (Fig. 7) are carried out.

Example.

A thin-walled cup 1 (Fig. 1) is made of steel mug “a” of steel 10 (sheet 5 mm thick GOST 4041-71) with a diameter of D ₀ = 130 mm and a hood on a hydraulic press with a force of 100 tf for 6 transitions with intermediate recrystallization annealing, while five transitions are carried out by hood without thinning the wall, and the subsequent sixth transition by hood with thinning of the wall with a limitation of the processing length to obtain a thickened wall at the end section of the workpiece.

The circle is set with a thickness t ₀ equal to 2.5 of the wall thickness t _{1 of the} finished glass: t ₀ = 2.5 × t ₁ = 2.5 × 2 = 5 mm.

Coefficients of drawing and diameters of the workpiece at five transitions:

1 transition “b”, k ₁ = 0.72, D ₁ = D ₀ × k ₁ , D ₁ = 130 × 0.72 = 93.6 (mm);

2 transition “c”, k ₂ = 0.8, D ₂ = D ₁ × k ₂ , D ₂ = 93.6 × 0.8 = 74.9 (mm);

3 transition “d”, k ₃ = 0.85, D ₃ = D ₂ × k ₃ , D ₃ = 74.9 × 0.85 = 63.65 (mm);

4 transition “e”, k ₄ = 0.875, D ₄ = D ₃ × k ₄ , D ₄ = 63.65 × 0.875 = 56.57 (mm);

5 transition “f”, k ₅ = 0.885, D ₅ = D ₄ × k ₅ , D ₅ = 56.57 × 0.885 = 50.06 (mm).

A glass blank is obtained with dimensions t ₀ = 5 mm, D ₅ = 50.06 mm and a final inner diameter of D ₅ - 2 t ₀ = 50.06-2 × 5 = 40.06 mm.

6 transition "g" is performed with the degree of deformation of the thinning of the wall

Get a glass blank for distribution with dimensions:

t ₁ = 2 mm, D ₁ = 40.06 + 2t ₁ = 44.06 (mm), the thickening length l _ut = 15 mm.

Then perform the distribution of the end part of the glass with a diameter of D ₁ = 44.06 mm to a diameter of D ₃ = 82 mm

The thickening is machined to form a welded edge for assembly-welding with dimensions t _ut = 5 mm, l _ut '= 10 mm and l _st = 10 mm.

Thin-walled shell 2 (Fig. 2) is made of a circle “a” of steel 11YA (strip 22 mm thick GOST B 19032-73) with a diameter D ₀ = 150 mm and a thickness t ₀ = 22 mm, first by extrusion of the thickened part on a mechanical crank press with a force of 4000 tf for two transitions “b” and “c” with intermediate recrystallization annealing at a temperature of 650-680 ° C.

At the first transition "b" get the workpiece with diameters D ₀ = 150 mm, D ₂ = 120.4 mm and a height of 30 mm with a flat bottom, at the second transition "c" with diameters D ₁ = 150 mm, D ₂ = 120.4 mm with a convex-concave bottom with a height of 35 mm ..

Then the hood is drawn with thinning the wall of the cylindrical part of the shell for three transitions “d”, “e” and “f” with intermediate recrystallization annealing at a temperature of 650-680 ° C.

Wall thicknesses and degrees of deformation at transitions:

1 transition

t ₁ = (150-120.4) / 2 = 14.8 mm, t ₂ = 8 mm,

2 transition

t ₂ = 8 mm, t ₃ = 5 mm,

3 transition

t ₃ = 5 mm, t ₄ = 2.3 mm,

A shell is obtained with an inner diameter of D ₂ = 120.4 mm and an outer diameter of D ₂ = 120.4 + 4.6 = 125 mm.

After that, crimping and calibrating the crimped section along the inner diameter of the hydraulic press with a force of 100 tf is performed.

After crimping and calibration get D ₃ = 82 mm, l _St = 15 mm

Perform machining with trimming of the end face for assembly-welding with the formation of a welded edge (l _st = 10 mm, D ₃ = 82 mm) with a bevel of the edge at an angle of 45 ° and a blunt edge of 1 mm.

Alternatively, the thin-walled part of the sheath 2 (Fig. 3) is obtained from the tube billet “a” of steel 10 (∅130 × 2.5 GOST 8734-75) by crimping and calibrating the crimped section along the inner diameter and machining to form a welded edge (l _st = 10 mm, D ₃ = 82 mm) on one of the ends with a bevel angle of 45 ° and a dull edge of 1 mm (Fig. 3, view A) and the other edge on the second end (Fig. 3 view B) with a diameter D ₄ = 88 mm, equal to the diameter of the welded edge of the bottom, with a bevel at an angle of 45 ° and a blunt edge of 1 mm.

Get the outer and inner diameters of the shell 2 (Fig. 3) D ₂ '= 110 mm, D ₂ = 125 mm, D ₃ = 82 mm, D ₄ = 88 mm and the welded edges l _ST = 10 mm

The thickened bottom part is obtained from the circle “a” (Fig. 3) of steel 20 (strip GOST 1577-93) with a diameter of D ₀ = 96 mm and a thickness of t ₀ = 22 mm by extrusion on a mechanical crank press with a force of 4000 tf in one transition.

The welded bottom edge is machined for assembly-welding (Fig. 3, view B) of the locking joint with a bevel edge at an angle of 45 ° and a blunt edge of 1 mm.

Assemble the butt joint of the thin-walled part of the shell and the thickened bottom part in the fixture on the assembly-welding installation of the mod. USN-250-500A with a technological gap of 1 mm at the junction and subsequent automatic welding with a consumable electrode in a mixture of protective gases of the composition: 80% Ar and 20% CO ₂ .

A thin-walled cup 1 and a shell 2 prepared for assembly-welding (Fig. 1, Fig. 2, Fig. 3 and Fig. 7) are made with the diameter of the welded edges D ₃ = 82 mm in accordance with the formula D ₃ = (0.4 -0.6) (D ₁ + D ₂ ), i.e. 82 = (0.4-0.6) (44 + 120.4) = (0.4-0.6) 164.4, total 82 = 0.499 × 164.4, which corresponds to the claims (D ₃ = (0.4-0.6) (D ₁ + D ₂ )), where D ₁ is the outer diameter of the workpiece 1 before distribution (D ₁ = 44 mm) ; D ₂ - the inner diameter of the billet shell 2 to crimp (D ₂ = 120.4 mm).

The end base 3 of FIG. 4 are made by machining from a steel billet 10 from a 85 × 10 pipe according to GOST 8734-75 with dimensions: outer diameter ∅80 mm, length of the welded section for assembly-welding of the corner lock joint l _sv '= 10 mm, diameter of the welded section for assembly-welding ∅ 78 mm.

Then the assembly and welding of the subassembly in the fixture on the USN-250-500A installation of the angular locking joint of the central tubular element - the cup 1 with the end base 3 (Fig. 4 and Fig. 5 is a view A from Fig. 4).

On the welded edges of the tubular element - cup 1 (Fig. 4 and Fig. 6, view B from Fig. 4), at the junction of the edges, the edges are beveled at an angle of 45 ° with a blunt edge of 1 mm for subsequent assembly and welding with a thin-walled shell 2. Conduct ^{pneumatic testing} for leaks with a pressure of 0.5 ^{+ 0.05} MPa (5.0 ^+0.5 kgf / cm ² ) with holding at this pressure for at least 1 min. Air leakage through the walls and the weld is not allowed.

Then, protective coatings (varnish FL-559 (2) GOST 14147-80.IV. UHL2) are applied to the outer surface of the tubular element - thin-walled cup 1 of the subassembly (Fig. 4 - the coating is shown by dotted line B) and the inner surface of the thin-walled shell 2 (Fig. 2, Fig. 3 - the coating is shown by the dotted line D), while the welding site is protected from the presence of a coating over a width l _st = 10 mm (Fig. 2, Fig. 3 and Fig. 4).

Build the butt joint of the subassembly (Fig. 4) with a thin-walled shell in the fixture on the installation of assembly-welding mod. USN-250-500A with a technological gap of 1 mm at the junction (Fig. 8) and subsequent automatic welding with a consumable electrode in a mixture of protective gases of the composition: 80% Ar and 20% CO ₂ in one pass. The width of the seam is 5 mm (min), the height of the seam is 3 mm (max) (Fig. 8).

Pneumatic tests are carried out for tightness with a pressure of 0.5 ^{+ 0.05} MPa (5.0 ^+0.5 kgf / cm ² ) with holding at this pressure for at least 1 min. Air leakage through the walls and the weld is not allowed. X-ray television monitoring to detect internal defects in the weld metal and near-weld zone (lack of fusion, pores, slag inclusions) is carried out on an X-ray apparatus YXLON MG-226 / 2.25.

Final machining of the ends of the threaded holes is performed (Fig. 7).

The implementation of the method of manufacturing a steel axisymmetric welded structure, in accordance with the invention provides dimensional accuracy, manufacturability, structural strength of welded joints not less than 0.9 of the strength of the base metal and the operational reliability of the entire welded structure.

The invention can be used in the manufacture of welded pressure vessels in various economic fields in the manufacture of fire extinguisher bodies, gas cylinders, liquefied gas cylinders for the automotive industry, receivers, etc.

Currently, technical documentation has been developed, tests have been carried out and mass production is being conducted according to the proposed method.

Claims (9)

1. A method of manufacturing a steel axisymmetric welded structure containing an end base, a central tubular element and a thin-walled shell, comprising forming the welding edges of the central tubular element under the lock connection, assembling the subassemblies through the lock connection, welding to the central to the tubular element of the end base by automatic welding in a protective gas environment, conducting pneumatic tests of the tightness of the weld, assembly and welding of the resulting subassembly with a thin-walled shell in the welding-assembly fixture, final machining and pneumatic testing of the tightness of the welds with internal pressure, characterized in that the central tubular element is made of sheet steel in the form of a mug in the form of a thin-walled cup by drawing without thinning the wall for several transitions with intermediate recrystallization annealing, at the last transition of which an extraction is performed with thinning of the wall to obtain an end thickening, distribution and machining of the thickening I with the formation of a welded edge for assembly-welding, a thin-walled shell is made with a thickened bottom of steel sheet in the form of a circle, with the first extruding the bottom part, then drawing out with thinning the wall of the cylindrical part for several transitions with intermediate recrystallization annealing, or thin-walled shell with a thickened bottom the assembly is made of bottom and cylindrical parts, the resulting thin-walled shell is crimped and the crimped section is calibrated according to its inner diameter and machined with cutting of the end face for assembly-welding, the end base is made of steel pipe billet by machining, then assembly-welding into welding assembly fixture of the angular locking connection of the central tubular element with the end base, carry out pneumatic tests, apply protective coatings on the bunks the narrow surface of the tubular element and the inner surface of the thin-walled shell, assembly and welding of the resulting subassembly with a thin-walled shell, they carry out a butt weld, carry out pneumatic tests of the tightness of welds, X-ray television control of the butt weld and final machining. 2. The method according to p. 1, characterized in that for the manufacture of a thin-walled glass using sheet steel in the form of a circle, a thickness equal to 2.0-2.5 of the thickness of its wall. 3. The method according to p. 1, characterized in that thin-walled shell with a thickened bottom they are made of a team from the bottom, which is obtained from sheet steel in the form of a circle extrusion and a cylindrical part, which is obtained from a steel pipe billet with their subsequent assembly-welding. 4. The method according to p. 1, characterized in that the diameter of the welded edges in the castle connection of a thin-walled glass and thin-walled shell equal to (0.4-0.6) (D_one+ D₂), Where: D ₁ (mm) is the outer diameter of the glass blank before distribution; D ₂ (mm) is the inner diameter of the shell preform to crimp. 5. The method according to p. 1, characterized in that on the welded edges of a thin-walled cup and a thin-walled shell with a thickened bottom at the junction of the edges, the bevel of the edges is performed at an angle of 45 °, and when assembling and arc welding the butt joint with a consumable electrode in a protective gas environment in one pass in the fixture provide a technological gap of 1 mm at the junction. 6. The method according to p. 1, characterized in that when applying protective coatings to the outer surface of a thin-walled cup welded to the base and the inner surface of a thin-walled shell with a thickened bottom, the welding site is protected from the presence of a coating of at least 10 mm wide.

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