RU2695855C2 - Method of metal sheets explosion welding - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: invention can be used to produce large-thickness bimetallic parts by explosion welding. Sheet billet of bronze with thickness of at least 30 mm is divided into at least two fragments along their contact area. Stack of stainless steel sheet stock of not less than 60 mm in thickness and first fragment of sheet billet of bronze is assembled. Portion of the powdered explosive is laid with the calculated value of the deforming pulse on the surface of the first fragment and its welding is performed. Second and subsequent fragments of the sheet billet from bronze are successively welded by explosion on the area of contact until a bimetallic solid part of the required thickness is obtained. Prior to welding, the stack is placed in the demountable explosive to be destroyed during the explosion, and each portion of the explosive is placed in the limiting housing. Value of deforming impulse of each portion of explosive is calculated depending on thickness of corresponding attached fragment on the basis of experimental data.

EFFECT: method ensures production of strong welded joint without cavities.

1 cl, 6 dwg, 1 ex

Description

The alleged invention relates to the field of explosion welding technology and can be used to connect large-thickness metal parts by welding.

The relevance of the problem being solved is based on the difficulties associated with obtaining a welded joint of large-thickness (metal sheet thickness over 30 mm) parts, because to obtain such a compound, it is necessary to use a correspondingly large calculated mass of explosive (BB), which will inevitably lead to the destruction of the connected workpieces. It was assumed and experimentally confirmed that by fragmenting the initial blanks, it is possible to achieve a significant reduction in the mass of the used VM with the serial connection of fragments of parts.

The prior art method for producing large-sized bimetallic steel sheets - titanium by explosion welding (RF patent No. 2174458, IPC B23K 20/08, publ. 08/27/2003), according to which technological plates are welded to the main sheet on the same level as the clad surface around the entire perimeter from steel with a thickness of 0.7-1.0 thickness of the cladding sheet and a width equal to its overhang. The surface of the plates is smoothed to a metallic luster. Welding is done with an intermittent seam with a pitch of more than 100 mm from the side opposite to cladding. The assembled package on the support is placed at an angle of 3-6 ° to the horizon. The welding gap is filled with argon from the bottom of the bag. The upper part of the support is made of a layer of sand heated to 60-150 ° C. The known method allows to obtain bimetal steel-titanium of high quality and bond strength with a smooth and even edge, without lack of fusion, chips, tears.

The disadvantages of the analogue are the insufficiently high quality of the weld at large thicknesses of the cladding sheet (≥ 30 mm).

As a prototype of the proposed method of obtaining flat bimetallic titanium steel blanks (RF patent No. 2211125, IPC B23K 20/08, publ. 10.10.2001), in which a fixed plate is installed on a rigid base. With a gap relative to it and with overhanging around the perimeter of the fixed plate, a throwable plate is arranged. Place a charge of explosive (BB) on it and initiate it.

The disadvantages of the prototype are the insufficiently high quality of the weld with large thicknesses of the cladding sheet (≥ 30 mm).

The task of the authors of the invention is to develop a simple effective method for welding large-thickness sheets of metals, with obtaining a durable weld-free, without voids, while reducing the brisance of the used explosive masses.

A new technical result when using the present invention is to provide in the welding process of large-thickness metal sheets a high-quality solid weld without voids, while reducing the brisance of the explosive masses used.

The specified task and a new technical result is ensured by the fact that in the method of explosion welding of thick metal sheets, including preparing samples of dissimilar metals, assembling a package of metal samples and from explosive material (EXPLOSIVES), subsequent initiation of detonation of EXPLOSIVES and explosion welding, according to the invention, a sample of metal of lesser thickness is divided into at least two or more fragments along the contact area of the parts, then the sample is assembled sequentially from the outcome metal and the first fragment of a metal of smaller thickness, which are welded together, and then the remaining fragments are sequentially welded over the area of contact with the first metal fragment, while the assembly is placed first in a collapsible matrix, which is destroyed during the explosion, on top of the assembly from the side of the first first of a fragment, a charge of an explosive powdery substance (BB) is placed with a given value of a deforming impulse placed in a restrictive housing, a charge of an explosive is initiated, then subsequent fragments comrade, they perform explosion welding to obtain a bimetallic integral part, while the strain momentum of each portion of the explosive charge is calculated depending on the thickness of the corresponding attachment fragment, the assembly of the packet from series-connected fragments is carried out until the specified thickness of the bimetallic component is reached, the detonation of the next explosive charge is initiated, alternating the attachment of the subsequent metal fragment and the explosive layer with explosion welding.

The proposed method is illustrated as follows.

Initially, samples of dissimilar metals are prepared and appropriate materials and operations are selected for different pairs of metals to be joined. In FIG. 1 shows an assembled package of joined fragments of the assembly, where 1 plate is thicker. The plate (2) of smaller thickness is divided into fragments (two or more) along the welding plane and placed in a cage 4, designed to exclude the negative effects of lateral unloading waves. The assembled bag is shown in FIG. 1. Then take a sample of explosives (3) (ammonite), the mass of explosives is calculated in accordance with the thickness of the cladding layer.

Then collect the package from the selected metal sheets. Initiate a rolling detonation of the explosive layer and sequentially produce explosive connection of the sheets.

The parts obtained by explosion welding are sent for control tests on the quality of the weld.

Indestructible control method (ultrasonic diagnostic method based on the general principles of EN583-1).

Destructive control method. The control fragment of the bimetallic part is subjected to tensile testing (samples are prepared according to GOST 1497 and tested on an INSTRON-type installation).

Thus, the use of the proposed method allows in the process of welding large-thickness sheets of metals to achieve high-quality solid solid weld-free, without voids, while reducing the brisance of the used explosive masses.

The possibility of industrial implementation of the invention is confirmed by the following examples.

Example 1. In laboratory conditions, the proposed method is tested on a prototype (layout) for sheets of stainless steel and bronze.

Required bimetal thickness: stainless steel 60 mm; bronze 30 mm. Dimensions of a workpiece made of bronze 300 × 90 × 30 mm.

Previously, a sheet of smaller thickness (bronze) is divided into three fragments along the welding plane. The thickness of each fragment was 9.5 mm.

The sequence of operations:

1- thicker plate made of stainless steel; 2 - a plate of smaller thickness made of bronze; 3 - charge powder BB; 4 - steel clip.

In FIG. 2 - shows the sequence of operations during explosion welding of sheet 2 of bronze with sheet 1 of stainless steel.

The thick steel sheet is mounted on an aligned sand cushion. A technological gap (5 mm) is maintained between the tossed and fixed sheets by means of racks - corners (a fragment of the tossed sheet is placed in a clip).

The purpose of the cage is to eliminate the negative impact of side unloading waves on the explosion welding process and the quality of the weld. In FIG. 3 shows a layout diagram of a bronze plate in a holder, where a bronze plate 2 in a holder 4.

A container (box) of cardboard is placed on the surface of the sheet to be thrown, into which a powder explosive is poured (ammonite AT-3; AT-2), the thickness of the explosive layer is 75 mm. Powdered explosive is initiated along one line with the help of a replenishing charge of a blasting explosive in the form of a bar ∅ 3 mm.

After blasting and collision (explosion welding), the surface of the projectile sheet is cleaned of traces of explosion products (PV) and other contaminants. A clip with a second throwable sheet and a container with a powder explosive are installed above it through a technological gap. The process (explosive loading) is repeated. Repetition can be performed several (arbitrarily) times until the required thickness of the bimetallic part is achieved.

In an example of a specific embodiment, three explosions were performed (three explosion welds). Macro and micrographs of the workpiece are shown in Figures 4, 5.

In FIG. Figure 4 shows a photograph of the contact boundary of SS-Br and two contact boundaries of Br-Br. The photograph shows a macro section of the contact boundaries SS-Br, Br-Br, Br-Br.

In FIG. 5 - a photograph of a microsection of the contact boundary of the SS-Br, enlargedx200. Strength tests showed that the gap occurred in bronze. The strength of the weld is bronze-steel and the welds of bronze-bronze are higher.

In FIG. 6 is a photograph of samples after a tensile test.

Claims (1)

A method of producing a bimetallic part from two plate blanks by explosion welding, comprising preparing plate blanks of dissimilar metals, assembling a package of metal blanks with the placement of explosives, the subsequent initiation of detonation of explosives and explosion welding of said blanks, characterized in that the sheet blank is made of bronze a thickness of at least 30 mm is divided into at least two fragments along the area of their contact, the package is assembled from a stainless steel blank hoist with a thickness of at least 60 mm and the first fragment of a bronze sheet metal, lay a portion of powder explosive with the calculated value of the deforming impulse on the surface of the first fragment and weld it, then sequentially weld by explosion welding over the contact area of the second and subsequent fragments of the bronze sheet metal to obtain a bimetallic solid part of the required thickness, while before welding the package is placed in a collapsible steel matrix that is destroyed during the explosion, each portion The explosives are placed in a restrictive housing, and the magnitude of the deforming impulse of each portion of explosives is calculated depending on the thickness of the corresponding attached fragment.

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