RU2036063C1 - Method of making laminate metallic tubes - Google Patents

Abstract

FIELD: tube production. SUBSTANCE: method comprises steps of making a metallic strip by rolling, directly after the strip had been rolled, measure cutting it and upon winding the measure cut strip on a formate drum applying on it an easy meltable metal in the form of powder or a sheet with melting temperature no more, than 1100 C at temperature value of the steel strip less, than the above mentioned melting temperature of the easy meltable metal. In order to simplify an assembling procedure, to isolate the tube from action of gases and liquids and from corrosion, the metallic sheet is being wound on a hollow metallic core, being monolithic or of one sheet, having in its outer surface a shoulder with a height , equal to a thickness of the metallic sheet, and with a length, equal to a width of the measure cut blank, in such a way, that an end of the material to be wound is placed in a butt with the shoulder. An outer surface of the core is helical one due to a wound layer of high-strength metallic sheet. Upon cooling the laminate metallic tube its outer layers (due to their linear narrowing) force inner layers with a high effort, increasing diffusion of the assy meltable metal into layers of the rolled metallic sheet with preliminary stress of layers of the tube. EFFECT: enlarged using range. 2 cl, 3 dwg

Description

 The invention relates to the production of multilayer metal pipes of high pressure and can be used for the metallurgical, oil and gas and chemical industries.

 A known method of manufacturing multilayer metal pipes from steel sheets with a thickness of 4-5 mm by cutting a metal strip into measured billets, winding the measured billet in several layers onto a format drum, welding internal and external seams, welding shells to produce pipes. To eliminate the gaps between the layers (4-7 layers), the shell is put on after the welding of the external lap weld on the expander, expanding it with the necessary effort. After this, the welding of the internal lap weld is performed.

 However, this method of manufacturing multilayer steel pipes does not provide uniform transmission of the internal pressure of a gaseous or liquid medium due to the slipping of individual sections of a continuously wound sheet when the temperature of the outer and inner layers changes.

 The technical effect consists in increasing the density, strength and toughness of multilayer metal pipes.

This is achieved in that the metal strip obtained by hot rolling, cutting it to length is carried out immediately after rolling, and during the winding-dimensional preform the format roller performed applying to it a low-melting metal in the form of a powder or a sheet with a melting point not exceeding ¹¹⁰⁰ C. , when the temperature of the steel sheet is not less than the melting point of the fusible metal.

 To facilitate the assembly process, isolation of the pipe from the action of liquids and gases, as well as from corrosion, the metal sheet is wound onto a hollow metal core made of solid metal or from a sheet on the outside of which a step is made with a height equal to the thickness of the metal sheet and a length equal to the width measuring workpiece, positioning the end face of the wound material end-to-end with a ledge.

 The outer surface of the core is made in a spiral, respectively wound layers of high-strength metal sheet. The hollow core is made of refractory and stainless metals, depending on the conditions of use of the pipes, as well as from a rolled metal sheet. It is an integral element of the finished multilayer pipe.

 Figure 1 presents the process diagram; figure 2 and 3 product.

 The production of multilayer metal pipes (Fig. 1) begins with the preparation of a metal strip and welding of the internal lap seam of the metal core 1, and then ultrasonic inspection of the internal weld seam 2 is performed. After rolling, the metal strip 4 is edited and the strip 5 is checked in the case of if necessary, an additional electric arc heating 6 is made and the metal strip is cut into measured lengths 7. The heated measuring billet 8 is supplied to the format drum 9 for winding the shells.

 Prior to starting winding the shells, a metal core with a step on the outer surface located at the level of the metal strip is put on the format drum 9. The hot measured billet automatically joins the outer ledge of the metal core and a thin uniform layer of fusible metal powder is applied from the electric vibrator 10 or a thin sheet of fusible metal 11 is laid.

 After winding the metal strip with a layer of low-melting metal powder or with a thin sheet of low-melting metal, welding of the external lap weld 12. Instead of the external weld lap weld on the hot shell, the external weld was pressurized.

 The finished metal multilayer shell was fed to the place of machining of the ends 13 and then to the assembly of the shells 14 with welding of the inner ring 15 and outer ring seams 16. After the X-ray television inspection of the ring seams 17, the pipe 18 was hydrotested and the pipe ends were processed 19. After finishing assembly, multilayer metal pipes were transferred to the finished pipe warehouse 20.

 For a shell with an inner diameter of 1380 mm, taking into account the inner metal core, the number of turns is 4 pieces, the thickness of one turn is 5.4 mm. The circumference of the shell turns after winding: for the inner metal core 4311 mm without overlapping, for the first inner turn 4345 mm, for the second inner turn 4379 mm and for the third outer turn 4413 mm.

 During cooling of a multilayer metal pipe, the outer layers due to their linear narrowing squeezed the inner layers with great force, which increased the diffusion of the fusible metal into the layers of the rolled metal sheet with the preliminary stress of the pipe layers.

Low dimensional preform taken not less than the melting temperature of the low-melting metal powder 1000 ° ^C when using thin sheets of aluminum-manganese and aluminum-magnesium alloy with a melting point of 658 ^{° C} prior to winding dimensional preform has a temperature of 660 ^C. The quantity of heating a metal strip by using foil of tin and lead alloy taken as 240 ° ^C. We used the steel strip width of 1700 mm hot rolled low alloyed steel (09G2SF mark).

 Thanks to the collet design of the format drum, the finished multilayer shell with a metal core was easily removed from it and conveyed to the installation, where the outer end of the rolled metal sheet was finally processed. The ends of the shells with a length of 1700 mm before assembly into pipes of 12 m in length (7 pcs x 1.7 m) were processed on a metal cutting machine for subsequent welding. The joints of the shells were welded inside the pipe, and then outside.

 The finished multilayer metal pipe of large diameter (Fig. 2) consists of a metal sheet 21, a hollow metal silver 22 with a step on the core 23 and a layer of low-melting metal powder or a thin sheet of low-melting metal 24 and has an internal weld 25.

 Small diameter multilayer metal pipes were made with a solid-cast hollow inner core and a protective casing of refractory and stainless metals (Fig. 3), depending on the conditions of use of the pipes.

 The finished protective casing was heated to a temperature less than the melting point of the fusible sheet and in the heated state was put on a multilayer metal pipe after it was cooled to a temperature in the assembly shop. During cooling, the protective casing squeezed the multilayer metal pipe due to linear narrowing, increasing its density, strength and toughness.

 The use of low-melting metal for joining together layers of rolled steel sheets rolled on a mill made it possible to connect thin sheets so that they did not lose stability in the structural elements of pipes, which guarantees their high reliability and cost-effectiveness. A new material is obtained that combines the advantages of a multilayer and monolithic material in one product. In this case, the required strength is achieved with a smaller thickness, which is the case in the case of a monolithic metal made of expensive niobium steel. The oxidized metal surface was heated spontaneously when heated without access to air. The molten metal powder or low-melting metal sheet ate the oxidized film of the rolled steel sheet, which ensured the bond strength of all layers of the multilayer pipe. In this case, the molten particles of fusible metal penetrate into the pores of a metal sheet heated after rolling due to the diffusion of metals in the boundary surfaces of their contact under pressure.

 In addition to pipes for construction, multilayer high-strength metal pipes with a hollow metal core can be used in military affairs for gun barrels and launching devices, in the aircraft industry and in the space industry for rockets and nozzles, as well as for pipelines in other industries.

Claims (2)

1. METHOD FOR PRODUCING MULTI-LAYERED METAL PIPES, including cutting a metal strip into measured billets, winding the measured billet in several layers onto a format drum, welding inner and outer seams, butt welding to produce tubes, characterized in that the metal strip is obtained by hot rolling, cutting it is carried out on measured billets immediately after rolling, and in the process of winding a measured billet on a format drum, a fusible metal is applied to it in the form of a powder or a sheet with a melting temperature Nia not exceeding 1100 ^o C, the steel sheet at a temperature less than the melting temperature of the low-melting metal.  2. The method according to p. 1, characterized in that the winding of the metal sheet is carried out on a hollow metal core made of solid metal or from a sheet on the outside of which a step is made with a height equal to the thickness of the metal sheet and a length equal to the width of the measured workpiece, having an end face end-to-end winding material with a ledge.

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