SE467729B - MAKE TO JOIN PLASTIC MATERIAL MEDIUM EXPLOSION WELDING. - Google Patents

Description

Another special application is the use of carbon fiber reinforced plastic materials for the aerospace industry.

It is to be understood, however, that the present invention is applicable to most inacrylonolecular materials.

The present invention is explained and described below in connection with the accompanying drawings, in which - Fig. 1 shows a schematic sketch of an equilibration welding process. Fig. 2 shows a speed diagram. Fig. 3 shows another speed diagram. Fig. 4 illustrates different zones in an explosion welding process. - fig. 5 - 10 show different basic arrangements of two material parts, which must be exploded welded to each other. Figs. 11 a - 11 e show different exercplifier rider arrangements for joining plates or pipes.

Fig. 1 shows the flow of material which takes place in an explosion welding process. A first material part 1 is accelerated towards a second material part 2. The collision zone has been denoted by a. In reality, the collision front a moves from right to left in the image. 'Without the parties' relative movement scheme changing, one can theoretically imagine the collision zone stationary and that the material parts 1,2 move from left "to the right in the image.

The continuity condition of the process means that the velocity D is constant throughout the vector diagram of the material parts in Fig. 2 shows that the velocity v at which the first part of the material 1 is thrown towards the second part of the material 2 has the argument 4> = ß / 2 relative to the surface downwards and which during the process forms an angle ß towards the surface of the other material part 2.

Ifig. 2ärq> + 6 + 90 = 180 ° andß + 26 = 180 ° whyqb = ß / 2. 467 729 3 Fig. 3 illustrates the speeds in connection with an explosion welding process.

The velocity vector v has the components vv perpendicular to the collision surface of the other material part 2 and vh parallel thereto.

The coniposity vv is momentarily decelerated in the collision and gives rise to a pressure wave, which moves partly upwards in the material part 1 and partly downwards in the material part 2.

If the amount of the grain poscent vvz is large enough, the pressure generated near the collision surface becomes high enough to fluidize the material. Within certain limits, the viscosity of the fluidized material may be affected.

Furthermore, the fluidization depth on both sides of the collision surface is affected by the amount of vv.

The component vh is the velocity difference between the colliding surfaces of the material parts 1,2, which affects the formation of the joint in such a way that when its amount reaches a certain value, the current between the fluidized slides of the material parts 1,2 changes from laminar to turlaulent. with the viscosity.

When the pressure in the joint surface ceases, the fluidized bed closest to the collision surface solidifies and the turbulent wave pattern is "frozen", as illustrated in Fig. 4.

The pressure wave generated during the collision is reflected against the surfaces of the material parts 1,2, which are opposite the collision surfaces. After the reflection, the pressure wave returns to the joint surface as a tensile wave, whereby the joint area is relieved.

Fig. 4 illustrates the liquid zone of material, which Iippkomxner with a rasterized area 3. With the lines 4 resp. arrows 5 illustrate the distribution wave resp., respectively, resulting from the collision between the material parts. rikiznizig. With lines 6 resp. arrows 7 illustrate the distribution of the pressure wave reflected towards the surfaces 8,9, resp. direction.

The reflection points are indicated by the numbers 10 and 11. ~ l> ~ PJ xO As illustrated in Fig. 4, the liquid zone solidifies when it p.g.a. that the traction wave running inwards from the surfaces 8,9 reaches the fogox node, the said 12 being frozen.

Lines 13, 14 illustrate the extent of the solidified joint area.

It is known in explosion welding of metals that the anxiety and wavelength of the "frozen" wave pattern increases if the time until the tensile wave relieves the fogol range increases. This is because the turbulence or weighing car initiated at the front of the collision increases in amplitude and wavelength “when the tens of meters closest to the joint is liquid. Increasing Inaterialtjoclšlelí hOS nlaterialpartene that the time at which the tensile wave coexists to the joint area is later, relative to the time of collision, so that the wave pattern and wavelength of the wave pattern thereby increases. The said time is of course also highly dependent on the material's shock wave velocities.

The shock wave velocity of a material is equal to the sound velocity of the material at shock waves with lower amplitude and a function of the sound velocity at higher shock wave splits.

If the time between the time when the material parts collide to the time when the wave pattern is frozen becomes long, e.g. Due to the low shock wave velocity, the turbulence tends to increase so much that strong vortex images accumulate, which in turn cause such a high temperature through internal friction that the material melts tennis. This gives cavities in the finished joint, which Itünskar its strength.

The above regarding the course of explosion welding also applies to explosion welding of metals.

The shock wave velocity for nxalu-anolelgla organic materials is generally significantly lower than for metals. This means approaching the time until the joint area is relieved to be long. This gives acc. the above-mentioned cause of great turbulence and vortex formations with internal cavities as a result.

In addition, since the melting temperature of macronolecular materials is very low compared to that of metallic materials, a significant thermal melting of the material easily occurs in the joint area. 467 729 Explosion welding of macrosolecular materials, such as plastics, can therefore not be performed using the parameters applied in explosion welding of metals.

The present mippfiimag discloses a method of joining materials consisting of or as a constituent in the age of inachronzolecular organic compounds, in which at least a first of the material parts to be joined is accelerated to high speed by means of one or more detonating explosive charges and allowed to collide with a second part in a joint plane, ie one way an expleeieneevetee micremeleclare material.

It has surprisingly been found that if the arguments and amounts of the said vector v are adapted in the manner indicated below to the yield strength of the macronutrient materials, shock wave velocity and velocity of the particles, a high quality explosion joint is obtained.

According to. According to the invention, the relative velocity vv in a direction perpendicular to the said surface of said second material part towards the first material part, i.e. perpendicular to the joint plane, at which speed the material parts collide with each other, is made such that the pressure which arises between the material parts 1,2 at the collision between them is higher than the material's buoyancy, but less than twice the yield strength while the collision successively direction parallel to said surface of said second material part, i.e. parallel to the joint plane, is caused to run at a speed D between cnnkriilg 1000 m / s and 2000 m / s, preferably between 1400 m / s and 1700 m / s.

According to. a preferred embodiment is said collision pressure between 5 and 20 times the yield strength.

As a comparison, it can be said that in explosion welding of metals, the collision pressure is more than 50 times higher than the yield strength of the metallic materials.

It has been found that a speed higher than about 2000 m / s causes too low-noise shock waves, which after said reflection destroy the fogox node and / or the material in the material parts. 467 729 The explosives to be used in the present process are thus explosives with a low detonation rate. For example, powdered explosives diluted with an inert material can be used. The number of possible explosives is very large. for example, nitroglycerin excipients are suitable. One such is an explosive, which is marketed by Nitro Nobel, _ Sweden under the brand name GURIT. Another suitable explosive is Nitroguanidine (CH4N4O2). The specialist arm can easily arrange an explosive with a detonation speed suitable for the present application.

If, as is usual in the combination of plasma materials, the thickness of the material parts and the wave weight characteristics are equal, it is obtained according to the above-mentioned collision of the two reflected pressure wave grooves precisely in the newly formed and not yet solidified joint layer, which collision tends to tear the joint apart.

This is particularly problematic when explosion welding is to be performed on non-carbon materials.

This problem is avoided according to several preferred embodiments of the invention.

According to. a first embodiment, in which both material parts 1,2 have a substantially or exactly true thickness perpendicular to the joint plane, there is present at the free surface of one material part a buffer material, the shock wave impedance, i.e. the density x the speed of sound, is essentially the same as the shock wave impedance of the material part against which the hiffertnx material abuts.

In Figs. 5 and 6, the numbers 1 and 2 denote the parts of the material, the number 15 the buffet material and the number 16 the explosive or the impulse means.

According to. In another embodiment, material parts 1,2 with different thicknesses perpendicular to the joint plane are used, as illustrated in Figs. 7 and 8, where the explosive charge is denoted by the number 16. This avoids a strong tensile wave in the joint area.

Fig. 7 illustrates a common arrangement before detonation of the explosive charge, where the two material parts 1,2 are mutually parallel. In such an * arrangement, the speed D of the collision front must thus be regulated only by means of the choice of explosive.

'N 467 729 7 Enl. In a preferred embodiment, which is illustrated in Fig. 8, the two material parts 1,2, before joining, have the surfaces to be joined together so arranged that they form an angle towards each other. According to. In this embodiment, the speed D of the collision front can be adjusted by adjusting the angle between the material parts 1,2.

For macronolecular materials which require the velocity of the collision front to be in the lower of the above speed range, it is advantageous to select a low detonation velocity explosive and to arrange the material parts 1,2 at a mutual angle, as illustrated in Fig. 8.

At the events according to Figs. 6 and 7, the explosive charge is caused to act directly on the material part 1 to be accelerated.

An alternative, mainly for materials, where the speed of the collision front must be low, is acc. a further preferred embodiment that the explosive charge is caused to indirectly affect the material part 1 to be accelerated via a material inert to the detonation, which is illustrated in Fig. 9.

In Fig. 9, the numeral 17 denotes the inert material. This material or ice transfer medium can be, for example, plastic, gunmi, Install, plaster, paraffin or a liquid of suitable choice and order, in order to reduce the speed D of the collision front to a desired value.

According to. In another embodiment, which is illustrated in Fig. 10, said inert material is constituted by a projectile flange 18, which is caused to be accelerated by means of the explosive charge 16 towards the first material part 1 and collide therewith to thereby accelerate the first material part 1 towards the second material part 2. This reduces the speed of the collision front.

The projectile body 18 can be made of plastic, glmuni, metal, plaster, wood fiber, etc. and can either be plane-parallel, as shown in Fig. 10, or have a varying cross-section.

The projectile body 18 can also be such that it is welded to the first part of the material 1. In the embodiment according to Figs. 9 and 10 also cause the inert material to reduce the pressure which arises between the two: the material parts 1,2 in their collision compared with if the explosive charge gene acts directly against the first material part 1.

Figs. 11a-11e schematically show various exemplary arrangements for explosion welding of two material parts 1,2 of Inacroxnollable material, where the materials are in the form of flat plates or are tubular.

When pipe-shaped materials are meant, Figs. 11a-11 show a section along a radius. The number 19 indicates explosive charges. _ According to. one embodiment each of said material parts 1,2 consists of a homogeneous material.

However, according to In another embodiment, one or both parts of the material consist of a composite material, such as a composite material or a laminate.

Practical experiments have shown that a surprisingly good joint is obtained when two material parts of plastic are sanunarx jointed according to present invention.

The present invention thus provides a method of explosion welding malcromolecular materials to each other.

Of course, the choice of and of the material parts before joining, of superfluous material, a material inert to the detonation or a projectile shell, as well as the angle between the material parts before joining must be adapted to the macro-molecular material in question, in order to achieve the conditions stated in the claims. Such an adaptation does not present any problems to the person skilled in the art.

The present invention is not to be construed as limited to the embodiments set forth above or the embodiments exemplified in the figures, but may be varied within the scope of the appended claims.

Claims (10)

f 467 729 Patent claims A method of joining materials consisting of or consisting essentially of macromolecular organic compounds, in which at least one first (1) of the material parts to be joined with a second (2) part of material is accelerated - at high speed by means of one or more detonated explosive charges (16; 19) and is allowed to collide with the other material part (2) in a joint plane, characterized in that the relative velocity (vv) in a direction perpendicular to the joint plane, at which speed the material parts (1 , 2) collide with each other, are caused to “be such that the pressure which arises between the material parts (1,2) in the collision is higher than the required pressure to obtain plastic deformation of resp. matter but less than 20 times the required pressure, at the same time as the collision is successively run in a direction parallel to the joint plane at a speed (D) between about 1000 m / s and 2000 m / s, preferably between 1000 m / s and 1700 m / s. 2. Set acc. claim 1, characterized in that said collision pressure is between 5 and 20 times said required pressure. 3. Set acc. claim 1 or 2, wherein both material parts (1,2) perpendicular to the joint plane have substantially or exactly the same thickness, characterized in that one part of the material (1; 2) abuts against a buffer material (15) at its free surface , whose shock wave impedance is substantially the same as the shock wave impedance of the matter (1; 2) of matter against which the buffer material (15) abuts. Ä. 4. Set acc. claim 1 or 2, characterized in that the material parts perpendicular to the joint plane have different thicknesses. 5. Set according to claim 1, 2, 3 or Å, characterized in that the material parts (1,2) before joining have the surfaces to be joined arranged so that they form an angle towards each other. 6. Set acc. any of the preceding claims, characterized in that the explosive charge (16; 19) is caused to act directly on the part of matter (1; 2) which is to be accelerated. 7. Set acc. one of claims 1 to 5, characterized in that the explosive charge (16) is caused to indirectly affect the material part (1) which is to be accelerated via a material inert to the detonation (17; 18). / 0 467 729 8. Set according to claim 7, characterized in that said inert material is a body (18) which is caused to accelerate towards the first material part (1) by means of the explosive charge (16) and collide with it so as to thereby accelerate the first material part ( 1) towards the other materlal part (2). u 9. Set acc. any of the preceding claims, it may be that each of said material parts (1,2) consists of homogeneous material. 10. a v, that one or both material parts (1; 2) consist of a combined material, such as Set acc. any of claims 1 - 8, characterized by a composite material or a laminate. _ ää