RU2397054C1 - Method for manufacturing of honeycomb from titanium alloys by means of diffusion welding - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention may be used to manufacture thin-walled titanium multilayer items with developed surface of contact, in particular for aviation industry. Material that prevents welding is applied onto sections of sheet billets that are not subject to connection. Heat resistant technological sheet gaskets are installed at sides opposite to connected section with the possibility to join sheet billets on connected section in process of their squeezing. Inside packet there are heat resistant gaskets with thickness that is twice more than thickness of gaskets arranged on external surface of extreme sheet billets of packet. Produced packet is heated and squeezed to connect sheet billets. Produced semi-finished product is deformed by means of stretching with formation of cells and arrangement of honeycomb block. Heat resistant gaskets may be made of nitrated sheet steel of Nitralloy group or sheet borated titanium.

EFFECT: invention solves problem of simplifying technology of manufacturing thin-walled honeycomb from titanium alloys with improved operational properties, expanded assortment and reduced prime cost.

2 cl, 3 dwg

Description

The invention relates to methods for manufacturing layered products consisting of layers of a honeycomb structure, namely, thin-walled titanium honeycomb aggregates for multilayer products of various lengths with a developed contact surface, for example, honeycomb panels used in the aerospace and aerospace industries.

A known method of producing a cellular filler for multilayer panels made of titanium alloys, which includes joining sheets of filler according to a specific pattern by welding, assembly with sheets of panel skin into a bag, sealing it along the circuit with the installation of gas pipelines, heating to a superplastic temperature of the material of the sheet blanks and molding by feeding the working media under pressure between the sheets of filler, until the formation of ribs of cells. (Description of the invention to the patent of the Russian Federation 2080225, IPC 6 В23К 20/00, В23К 101: 02, 1997.05.27).

A known method of manufacturing multilayer products from at least two sheet billets of titanium alloy by superplastic molding and diffusion welding, in which on the surface of at least one billet designate areas that are not subjected to connection and exposed, placing on the last technological gaskets from titanium alloy 3-4 times thicker than the thickness of the workpiece, collect workpieces with process gaskets in a bag, heat to a predetermined temperature and apply pressure Ress predetermined value for the compound workpieces by diffusion bonding to obtain a semifinished product. Then, heating and feeding the working medium under pressure into the inner cavity of the semi-finished product for superplastic molding and obtaining the product of the given shape is carried out (description of the invention to the patent of the Russian Federation 2291019, IPC B21D 53/78 (2006.01), B21D 26/02 (2006.01) 2007.01.10, prototype )

The use of technological gaskets made of titanium alloys, through which diffusion welding of the connected sections is carried out, allows to improve the quality of the welded joint, but at the same time the consumption of material and the weight of the product increase.

A common drawback of the known technical solutions is the complexity of the process of forming the cells of the aggregate, in which after welding the package carry out its distribution under conditions of additional heating. It requires expensive technological equipment and significant energy costs, and also does not allow the manufacture of large-sized cellular units.

The objective of the invention is the development of manufacturing technology for thin-walled titanium honeycomb aggregates for multilayer products of various lengths with a developed contact surface.

The technical result is a simplification of the manufacturing technology of a honeycomb core made of titanium alloys with improved operational properties, expanding the range and reducing the cost of manufactured honeycomb core.

The technical result is achieved by the fact that in the method of manufacturing a honeycomb core from titanium alloys by diffusion welding, in which the material that prevents welding is applied to sections of sheet blanks that are not to be joined, technological sheet gaskets, sheet blanks with technological gaskets are placed in areas to be joined collected in a bag, heated, squeezed until the sheet blanks are joined and a semi-finished product is obtained, and then, by deformation of the latter, the cells are formed and cells are obtained honeycomb, used heat-resistant lining and place them on the side opposite the connected portions, and are placed inside the package, heat-resistant gasket thickness twice the thickness of the spacers to be placed on the outer surface of the outer sheet pack blanks, and receive cell block semifinished stretching. Heat-resistant gaskets can be made of nitrided sheet steel of the nitralloy group or sheet of boron titanium.

Figure 1 shows a diagram of the preparation of a semi-finished honeycomb block, to the left of the axis before applying pressure, to the right of the axis after applying pressure; figure 2 - scheme for obtaining a cellular block from a semi-finished product; figure 3 is a fragment of the finished cell block.

The implementation of the method includes the following operations.

Preparation of blanks 1 with stop coating on areas that are not to be joined, and heat-resistant gaskets 2, 3, assembly of blanks with heat-resistant gaskets in bag 4, diffusion welding of sheet blanks 1 in bag 4 to obtain a semifinished product 5, and shaping the honeycomb block 6 by stretching the semifinished product 5 after removing the gaskets from it.

The preparation of sheet blanks is carried out by applying onto a thin-walled sheet material of a titanium alloy with a thickness of 0.2-0.3 mm of a material (stop coating) that impedes welding, in the form of strips with a width and in increments determined by the pattern of the fabricated honeycomb structure. The pitch is chosen equal to the width of the connected sections. The width is chosen less than the size of the half-perimeter of the cross section of the cell of the honeycomb structure by a predetermined amount of stretching of the non-connected sections of the workpiece upon receipt of the semi-finished product. The coating is applied on both sides of the sheet, placing the stripes on one with a step offset from the other. The coating can be obtained by thermochemical treatment, for example, in an active nitrogen gas environment. This further increases the compressive strength of the fabricated structure.

Next, the sheet is cut into strip blanks in a direction perpendicular to the stop coating strips with a width equal to the height of the manufactured honeycomb.

Heat-resistant gaskets 2, 3 are obtained from strip sheet material with a thickness exceeding the thickness of sheet blanks by at least 5-10 times. The width a is chosen equal to the width of the connected sections in the manufactured honeycomb structure. Inside the package 4, on the blanks 1, gaskets 2 with a thickness b are placed twice as thick as the gaskets 3 placed on the outer surface of the outermost sheet blanks of the package 4.

The thickness of the gaskets 3 placed on the outer surface of the outermost sheet blanks of the bag is selected based on the elongation of the sections of the blanks not to be welded in the process of squeezing the honeycomb packet by 1-15%.

The material for the manufacture of heat-resistant gaskets is selected from the condition of their repeated use. So, gaskets 2, 3 made of nitrided sheet steels of a group of nitralloids or sheet of boron titanium can be used in diffusion welding conditions, at least in 20-25 cycles.

Collect strip blanks with heat-resistant gaskets in a package by laying adjacent blanks with the sides of the blanks with the same arrangement of stop-coating strips facing each other, and heat-resistant gaskets overlapping the width of the central part of the stop-coating strips, while being located on the blanks with the opposite side of the areas without coverage, i.e. connected sections.

To carry out diffusion welding of sheets of blanks, package 4 is placed in stamp 7, under vacuum, heated to a polymorphic transformation temperature of the titanium alloy of the material of the blanks and pressed in two stages.

N·b для четного количества N листовых заготовок в пакете и

(N-1)·b для нечетного. Усилие сдавливания выбирают из условия равномерного растяжения заготовок. Напряжения растяжения являются благоприятными для осуществления деформации, необходимой для образования физического контакта между соединяемыми участками в процессе диффузионной сварки. На втором этапе соединяют заготовки сотопакета и усилие сдавливания выбирают из условия создания прокладками на соединяемых участках давления 2 МПа.At the first stage, corrugations of height b / 2 are formed on blanks by settling a honeycomb packet until the gaskets are closed in height. Precipitation -

N · b for an even number N of sheet blanks per bag and

(N-1) · b for odd. The compressive force is selected from the condition of uniform tension of the workpieces. Tensile stresses are favorable for the implementation of the deformation necessary for the formation of physical contact between the connected sections during diffusion welding. At the second stage, the honeycomb blanks are connected and the compressive force is selected from the conditions for creating gaskets on the connected pressure sections of 2 MPa.

Upon completion of the diffusion welding process, gaskets are removed from the preformed cells of the obtained semi-finished product, and the semi-finished product is stretched to obtain a honeycomb block with finally formed cells.

Claims (2)

1. A method of manufacturing a honeycomb core of titanium alloys by diffusion welding, in which the material that impedes welding is applied to sections of sheet blanks that are not to be joined, and technological gaskets are placed in sections to be joined, sheet blanks with technological gaskets are collected in a bag, heated , squeeze until the sheet blanks are joined to obtain a semi-finished product, and then by deforming the latter, cells are formed to obtain a honeycomb block, characterized in that use heat-resistant process gaskets and place them on the sides opposite to the connected area with the possibility of closing the sheet blanks on the joined section when they are pressed, and heat-resistant gaskets with a thickness twice as thick as the gaskets placed on the outer surface of the outermost sheet blanks of the package are placed inside the package, after connecting the sheet workpieces are removed from the process gaskets, and the semi-finished product is deformed by stretching. 2. The method according to claim 1, characterized in that they use heat-resistant gaskets made of nitrided sheet steel of the nitralloy group or sheet of boron titanium.

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