RU2620539C1 - Method of manufacture of thin-wall welded casings with end-draining outside from aluminium alloys - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: casing is made from a tube billet by rotational crimping of the curved section in several passes in a cold or hot state, then the rotary extraction of the cylindrical shell part is performed in a cold state, after which the sheath edges are trimmed; on the thickened rings, a slot is formed for the lock connection with the cladding, they assemble and weld the shell with rings in an automatic welding machine. Perform a visual inspection of the quality of welded joints, final machining with threading on welded rings and airtightness tests.

EFFECT: accuracy of geometric dimensions, quality of treated surfaces and strength of welded joints are ensured.

5 cl, 4 dwg

Description

The invention relates to the processing of metals by pressure and welding, and in particular to the production of welded vessel bodies and representing a thin-walled shell with thickened rings welded to it from aluminum alloys of the shell and rings of various chemical composition.

Welded vessel shells are used in various economic fields in the manufacture of fire extinguishers, cylinders, liners, receivers, etc.

Vessels are used both from steel and from aluminum alloys.

The advantage of aluminum alloy vessel bodies is their low weight.

The main requirements for welded bodies are as follows: high structural and cyclic strength, geometric accuracy, surface finish, high quality welded joints, high productivity and low weight.

A known method of manufacturing cylinders described in the book of MA The creditor “Squeezing and rotational extrusion”, Moscow, Engineering, 1971, pp. 58-63, consists in the fact that the tube billet at the end part is heated in the inductor of a high-frequency installation for a length of 5 ÷ 10 mm longer than the length of the deformable section.

A known method of manufacturing axisymmetric housings operating under pressure, RF patent No. 2295416, class. IPC B21D 51/24, C21D 8/10, which describes a method for the production of axisymmetric cases with end thickenings.

The method includes hardening, tempering, cold plastic deformation by rotational drawing in two passes, low-temperature annealing. Alloy steel is used, hardening and tempering are carried out, rotational drawing is carried out without intermediate annealing.

Also known is the "Method of seaming the neck of a balloon", RF patent No. 2002538, class. IPC B21D 51/24, by rotary machining by stepwise formation of the transitional and cylindrical sections of the neck at the heated end of the rotating tube billet.

The main disadvantage of the above methods for the manufacture of shells, shells and cylinders is the high complexity and cost of manufacturing, due to the formation by pressure treatment of all-metal vessels that do not have welded joints.

The closest in technical essence and the achieved technical result is a method of manufacturing high-strength axisymmetric shells operating under high pressure (Novikov OM et al. "New technology for arc welding in protective gas of high-pressure cylinders" magazine "Professional welder" No. 1, 2005, p. 14-15), adopted by the authors for the prototype, in which the machined part blanks are assembled using an assembly-welded fixture and the joints of a one-sided mechanized electric arc weld are welded an arch with a non-consumable tungsten electrode in two passes with filler wire feed in the second pass, with argon blowing from the inside from the root side of the seam, with alternating discrete (pulsating) supply of two protective gases - argon and helium to the continuously burning arc zone with simultaneous control of the arc voltage, then carry out final machining, hardening heat treatment, control and testing of welds.

This method requires expensive helium, a complex system for regulating the supply of two protective gases and controlling their consumption, controlling the pulsation of separate flows of protective gases in the optimal frequency range. In addition, there is no strict system for fixing joints in welding. Welding is carried out on weight, manually.

The reasons that impede the achievement of the technical result indicated below when using the known method of manufacturing thin-walled welded shells, adopted by the authors as a prototype, include the inability to accurately fix the parts to be welded, since welding is carried out by a canopy and manually, and high quality and accuracy of the processed surface are not ensured.

In the manufacture of vessel bodies from dissimilar aluminum alloys, in addition to the above problems, there is the difficulty of obtaining high-quality welded joints.

The objective of the technical solution adopted by the authors for the prototype is to provide high strength welded joints of steel cylinders.

Common features with the method proposed by the applicants are mechanical processing, assembly and electric arc fusion welding in a shielding gas environment and control of welded joints.

Unlike the prototype, the shell of the body is made from a tube stock by rotational crimping of the curved section for several passes in the cold or hot state, then the cylindrical part is rotationally drawn in the cold state, while the crimping and the hood are performed by deforming rollers with a radius of profile vertices exceeding 3 ÷ 6 times the minimum value of the wall thickness of the shell, then they trim the welded edges of the shell, and on the thickened rings form a landing groove for the castle connection with with a sponge, assembly and welding of butt joints of the shell with the rings at the automatic welding installation, visual inspection of the welded joints, final machining with threading on the welded rings and pneumatic testing for tightness of the welded body.

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

- rotational crimping of the curved section in the cold state is performed when processing shells of aluminum alloy AMts, and when crimping with gas-flame heating - from aluminum alloy AMg3;

- when performing electric arc welding with a non-consumable electrode of butt joint joints, the second pass is carried out with the filler wire of more durable material to be joined;

- when crimping and drawing the casing in a cold state, a composition consisting of industrial oil and an organofluorine-based surfactant of the “Universal Modifier UM” type is applied as a lubricant to the working surface of the rollers, mandrels and the outer surface of the workpiece with the following ratios of components, masses. %: (97 ÷ 85) and (3 ÷ 15), respectively;

- during the rotational crimping of the curvilinear portion of the shell with gas-flame heating, a lubricant in the form of an aqueous colloidal graphite solution PSV is applied to the working surface of the rollers and the mandrel, while the graphite is impregnated with 6MFK-180-05 fluororganic surfactant before preparation of the colloidal graphite solution and dried.

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 objective of the proposed invention is the manufacture of thin-walled welded cases with end thickenings of dissimilar aluminum alloys by rotary crimping, rotary hoods, welding and machining with high structural and cyclic strength, high quality welds, precision geometric dimensions, quality of the machined surface, high durability of the deforming tool, high metal utilization, high productivity and low weight.

The specified technical result and the implementation of the invention is achieved by the fact that in the known method, including the mechanical treatment of the shells, electric arc welding with a non-consumable electrode with rings in two passes with the filler wire in the second pass, control of the welded joints, the feature is that the shell is made of pipe blanks by rotational crimping of a curved section for several passes in a cold or hot state, then rotational extraction of the cylindrical part in x in the molten state, while crimping and drawing out are performed with deforming rollers with a radius of profile tips exceeding the minimum value of the shell wall thickness by 3 ÷ 6 times, then the welded edges of the shell are trimmed, and on the thickened rings a landing groove is formed for the castle connection with the shell, assembly is performed and welding of butt joints of the shell with rings at the automatic welding installation, visual quality control of welds, final machining with threading on welded rings and pnevmoispytaniya on Sealed, welded housing.

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

- the manufacture of the shell from the tube billet to increase the utilization of metal;

- rotational crimping of the curved section for several passes in the cold or in the hot state to obtain a profile section of the shell with high stability of the forming process by dividing the deformation into several passes of the crimp;

- rotary drawing of the cylindrical part in the cold state to obtain a cylindrical section of the shell;

- crimping and drawing out with deforming rollers with a radius of profile vertices exceeding by 3–6 times the minimum value of the shell wall thickness to ensure the stability of the forming process, since when the radius is less than 3.0 of the minimum values of the shell wall thickness, the surface becomes rough in the form of small corrugations , and with a radius value of more than 6 minimum thicknesses, the wall is thinned in the form of tightening, cracking and breakage of the workpieces in the deformation zones;

trimming the welded edges of the shell and the formation of the landing groove on the thickened rings to ensure coaxial assembly to obtain the locking butt joints of the shell with thickened rings and subsequent electric arc welding with a non-consumable electrode in the fixture on the automatic welding installation;

- assembly and welding of butt joints of the shell with rings at the automatic welding installation to ensure the production of high-quality welded joints in accordance with the requirements of design documentation;

- visual inspection of welds to check the quality of butt joints;

- final machining with threading on the rings to obtain a welded body, ready for connection with mating parts and devices for pneumatic testing;

- check pneumatic tests by welding the housing for leaks.

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

- performing a rotational crimping of the curvilinear portion of the shell made of aluminum alloy AMts in a cold state, and from an aluminum alloy AMg3 with gas-flame heating, to obtain a shell with high accuracy of geometric dimensions and quality of the processed surface, when crimping a shell of aluminum alloy AMg3, gas-flame heating is required, since - due to the higher manganese content in this alloy, cold deformation leads to cracks and breaks in the workpieces, the need to use AMg3 alloy is caused by its higher mechanical properties;

- performing electric arc welding with a non-consumable electrode of butt joints in the second pass with the filler wire of more durable material to be connected, to ensure the structural strength of the welded joints;

- applying during crimping and drawing the casing in the cold state on the working surface of the rollers, the mandrel and the outer surface of the workpiece as a lubricant for a composition consisting of industrial oil and an organofluorine surfactant of the type “Universal Modifier UM” with the following ratios of components, masses. %: (97 ÷ 85) and (3 ÷ 15), respectively, to reduce the wear of the working surface of the deforming rollers and mandrel, to improve the quality of the workpiece surface, when the fluorine-organic surfactant is <3% in the lubricant, the wear does not decrease, but when the content> 15% increase in the consumption of "Universal modifier UM";

- applying a rotary crimping of a curved portion of the shell with gas-flame heating to the working surface of the rollers and the mandrel of the lubricant in the form of an aqueous colloidal graphite solution PSV and impregnating graphite before preparing the colloidal graphite solution with an organofluorine-active substance 6MFK-180-05 and drying, reduce friction between the surfaces of the workpiece and the deforming rollers and the mandrel, reduce the deformation forces, increase the cleanliness and accuracy of the treated surface, exclude the cleaning of the rollers and mandrel, increase the resource of their work.

Signs that distinguish the proposed technical solution from the prototype are not identified in other technical solutions and are not known from the prior art in the process of conducting patent research, which allows us to draw conclusions about the compliance of the invention with the criterion of "novelty."

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 thin-walled welded bodies with end thickenings from dissimilar aluminum alloys containing a thin-walled shell with curved and cylindrical sections and thickened rings welded to them, including machining of the shells, arc welding with a non-consumable electrode with rings in two passes with filler wire feeding in the second pass, control of welded joints, in contrast to the prototype, according to the invention, making a shell they are removed from the tube billet by rotational crimping of the curved section for several passes in the cold or hot state, then the cylindrical part is rotationally drawn in the cold state, while the crimping and stretching are performed by deforming rollers with a radius of profile vertices exceeding by 3–6 times the minimum wall thickness shells, then they trim the welded edges of the shell, and on the thickened rings form a landing groove for the castle connection with the shell, assemble and weld the butt locks of the joints of the shell with the rings at the automatic welding installation, visual control of the quality of the welds, final machining with threading on the welded rings and pneumatic testing for tightness of the welded body.

The invention is illustrated by drawings, which depict:

- in FIG. 1 - welded vessel body containing a thin-walled shell 1 and thickened rings 2 and 3, I and II welded to it, annular welds, ring thickness t _k and t _{k '} (mm), shell thickness t _o6 (mm), D (mm) ) - case diameter;

- in FIG. 2 - view I and view II of figure 1 - butt weld joints in an enlarged view;

- in FIG. 3 - rotational crimping by two rollers 4 with a radius of peaks R _{1 of a} curved section of the shell 1 on the mandrel 5 with gas-flame heating by burners 6 connected to the rollers;

- in FIG. 4 - rotational hood of the cylindrical part of the shell 1 with three rollers 7 with the radius of the apex R ₂ on the mandrel 5 and the clamp 8.

In FIG. 3 and FIG. 4 - t _o (mm) is the thickness of the workpiece, t _o6 (mm) is the thickness of the shell, S min ^-1 is the rotation speed, F mm / min is the axial feed of the rollers.

The above method of manufacturing welded vessel bodies is as follows.

The blank of shell 1 made of aluminum alloy AMg3 or AMc obtained from the pipe (Fig. 3) is mounted on mandrel 5, fixed with a clamping device and subjected to rotational crimping of the curved section with two deforming rollers 4 with the radius of the vertices of the profile R ₁ (mm) on a double-support pressure a rolling machine for several passes with gas-flame heating by burners 6 when processing billets from aluminum alloy AMg3 and in the cold state when processing billets from aluminum alloy AMts.

During rotary crimping with flame heating, a lubricant in the form of an aqueous colloidal-graphite solution PSV is applied to the working surface of the rollers and the mandrel, while before preparing the solution, graphite is impregnated with a fluorine-organic surfactant and dried. When crimped in a cold state, a lubricant is applied to the working surface of the rollers, mandrels and the outer surface of the workpiece in the form of a composition consisting of industrial oil and an organofluorine surfactant.

Then, the cylindrical part of the shell 1 is rotationally drawn (Fig. 4) in the cold state on the mandrel 5 by three deforming rollers 7 with the radius of the vertices of the profile R ₂ (mm) on a three-roller pressing-rolling machine.

The shell during the rotation hood is fixed by the curved part of the inner surface on the curved outer surface of the mandrel 5 with a clamp 8.

When rotating the hood, a composition consisting of industrial oil and an organofluorine-surfactant is applied as a lubricant to the working surface of the rollers, the mandrel and the outer surface of the workpiece.

As a coolant, industrial oil is used.

After that, on screw-cutting machines, they trim the welded edges of the shell 1.

On rings 2 and 3 of a more durable aluminum alloy AMg5, a groove is formed under the castle connection with the shell (Fig. 2. view I and view II).

Then, assembly and welding of the butt joints of the shell with the rings at the automatic welding installation and visual quality control of the welds are carried out.

The final machining with thread cutting on the welded rings 2 and 3 is performed on screw-cutting lathes (Fig. 1).

In conclusion, perform pneumatic tests of the welded body for tightness at the installation of pneumatic tests.

Example

The tube billet shell 1 (Fig. 1) with a diameter of D = 375 mm and a thickness t _{o6 of} 2.5 mm from an aluminum alloy AMg3 or an alloy AMts is mounted on a mandrel 5 (Fig. 3). fixed in the spindle of a two-support press-and-roll machine of the Leikomat type TsNC 600 2C and fix it with a clamping device.

Then, rotational crimping of the curved section of the shell is carried out from a thickness of t _o = 5 mm to a thickness of t _o6 = 2.5 mm by two deforming rollers 4 with a radius at the vertices of the profile R ₁ = (10 ÷ 15) mm (R ₁ = (4 ÷ 6) t _o6 ) according to the CNC program of the machine for 4 passes with gas-flame heating during processing of shells from aluminum alloy AMg3 and in the cold state when processing shells from aluminum alloy AMts.

During the rotational crimping of the curvilinear portion of the shell with gas-flame heating, grease is applied to the working surface of the rollers and mandrels in the form of an aqueous colloidal graphite solution PSV, graphite is impregnated with a fluororganic surfactant 6 MFK-180-05 TU 6-02-1229-82 before preparing the solution and dried at a temperature of (80 ± 5) ° C.

When rotational crimping the curved portion of the shell in the cold state, a lubricant is applied to the working surface of the rollers, mandrels and the outer surface of the workpiece — a composition consisting of industrial oil grade I-20A GOST 20799-88 and the fluororganic surfactant “Universal Modifier UM” TU 2229- 002-27991970-94 with the ratio of components, mass. %: (97 ÷ 85) industrial oil and (3 ÷ 15) "Universal modifier UM".

Then, the rotary cylindrical hood portion of the shell 1 (Fig. 4) on the NC program of the machine with a wall thickness _of t = 5 mm and thickness t = 2.5 mm _{of the} three deforming roller 7 with a radius of vertices R ₂ = profile (10 ÷ 12) mm (R ₂ = (4 ÷ 4.8) t _o6 ) on a press-rolling machine of the Metallform type DV 450 for 1 pass in the cold state.

When the rotation hood, the workpiece is installed on the mandrel 5, mounted in the spindle of the machine, and fixed with a clamp 8.

When the cylindrical part of the shell is rotationally drawn in a cold state, a lubricant is applied to the working surface of the rollers, mandrels and the outer surface of the workpiece — a composition consisting of industrial oil grade I-20A GOST 20799-88 and the fluororganic surfactant “Universal Modifier UM” TU 2229- 002-27991970-94 with the ratio of components, mass. %: (97 ÷ 85) industrial oil and (3 ÷ 15) “Universal Modifier UM”, and industrial oil I20A GOST 20799-88 is used as cooling.

After that, they trim the welded edges of the shell.

Thickened rings 2 and 3 with thicknesses t _K = 25 mm and t _{K '} = 15 mm are made of tubes of aluminum alloy AMg5 (Fig. 1).

On the thickened rings, a landing groove is formed for the castle connection with the shell 1 (Fig. 2, view I and view II) in the form of a platform with a width of at least 10 mm and a diameter equal to the diameter of the edges to be welded, while at the junction of the edges to be welded, an angular groove is made for runoff of oxide captures during the welding process.

When assembling the thickened rings 2 and 3 with the shell 1, lock joints are formed that provide the required alignment of the mating parts of the welded body required by the drawing and prevent the formation of high penetrations and burns in the root of the welds during welding.

The assembled butt welded joints are welded in an automatic welding unit with a non-consumable electrode in argon shielding gas in two passes: the first pass to ensure weld root penetration without filler wire feeding, and the second with filler wire feeding in a composition identical to the stronger of the materials being joined.

If the sheath 1 (Fig. 1) is made of aluminum alloy AMg3 or AMts, and the more durable thickened rings 2 and 3 are made of aluminum alloy AMg5, then the filler wire is used from aluminum alloy AMg5, which ensures structural strength of welded joints.

After welding, visual inspection of the quality of the welds and final machining are performed.

When welding defects such as gas pores, slag inclusions, undercuts, and the geometric dimensions of welds are identified, the detected defects that exceed the permissible ones according to OST 92-1114-80 for category II welds are corrected after cutting and removing defects by welding them with an argon-arc non-consumable electrode.

In conclusion, perform pneumatic tests of the welded body for tightness at the pneumatic test installation with internal pneumatic pressure (0.30 ÷ 0.05 MPa) for at least 1 min, by immersion method according to RD V84-50-89.

The invention can be used in the manufacture of welded vessel bodies from aluminum alloys of various nomenclatures and sizes.

The indicated positive effect is confirmed by tests of welded vessel bodies made by this method.

Currently, technical documentation has been developed, tests have been carried out, serial production of products by the proposed method is planned.

The implementation of the method of manufacturing thin-walled welded cases with end thickenings of dissimilar aluminum alloys in accordance with the invention enables them to be obtained with high structural and cyclic strength, high accuracy of geometric dimensions, high resistance to deforming rollers and mandrels, high quality of the machined surface, high quality of welded joints, high metal utilization, high productivity and low weight.

Claims (5)

1. A method of manufacturing a thin-walled welded body with end thickenings from dissimilar aluminum alloys containing a thin-walled shell with curved and cylindrical sections and thickened rings welded to them, including the manufacture of a thin-walled shell with curved and cylindrical sections, its mechanical processing, assembly of the workpiece with rings, electric arc welding of a non-consumable electrode of a sheath with rings in two passes with filler wire feeding in the second pass, control of welded joints final machining and pneumatic testing for tightness of the welded body, characterized in that a thin-walled shell with a curved and cylindrical sections is made from a tube stock, the curved section being obtained by rotational crimping in several passes in a cold or hot state, then a cylindrical section is obtained by rotational drawing of a cylindrical parts in a cold state, while the rotational crimping and drawing are performed by deforming rollers with the radius of the vertices of the profile, p 3–6 times higher than the minimum value of the shell wall thickness, during machining, the welded edges of the shell are trimmed, and a groove is formed on the rings for the key connection to the shell, arc welding with a non-consumable electrode of the shell with rings is carried out by butt joint connections on the automatic welding installation, during final machining, threading is performed on the welded rings. 2. The method according to p. 1, characterized in that in the manufacture of shells of aluminum alloy AMts, the rotational crimping of the curved section is carried out in a cold state, and in the manufacture of shells of aluminum alloy AMg3, the rotational crimping is carried out with gas-flame heating. 3. The method according to p. 1, characterized in that when performing arc welding with a non-consumable electrode of the butt joint joints, the second pass is conducted with the filler wire of a material stronger than connectable materials. 4. The method according to p. 1, characterized in that when crimping and drawing the casing in a cold state, a composition consisting of industrial oil and an organofluorine-based surfactant of the Universal Modifier type is applied as a lubricant to the working surface of the rollers, mandrels, and the outer surface of the workpiece. UM "in the following ratio of components, mass. %: (97 ÷ 85)% and (3 ÷ 15)%, respectively. 5. The method according to p. 1, characterized in that during the rotational crimping of the curvilinear portion of the shell with gas-flame heating, a lubricant in the form of an aqueous colloidal graphite solution PSV is applied to the working surface of the rollers and mandrel, while graphite is impregnated with organofluorine before preparing the colloidal graphite solution type 6 surfactant MFK-180-05 and dried.

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