WO2020013734A1 - Method and device for double-action liquid forging - Google Patents

Abstract

The present method of liquid forging includes producing a metal melt by means of melting an ingot using an electromagnetic field of an inductor, which confines the lateral surface of the melt on a punch, and then moving the melt at a high speed into a die where the melt is crystallized in the volume of a component under the excess pressure of the punch. The body of the component is exposed to an additional pressure pulse created by a shock wave arising during the collision of a solid body embedding an additional needle punch into the metal, said needle moving at a high speed and generating higher pressure on the metal, which allows the process of casting under pressure to transition to a stage of crystallization of the metal under pressure.

Description

 METHOD AND DEVICE of double-forged liquid forging

 ACTIONS

The present invention relates to the field of casting and metal forming. The method can be used for the production of complex shaped parts from any metals, including refractory and chemically active ones. The method allows the production of parts with high strength properties, including the production of composite products.

 [1]. As an analogue of the invention, the invention adopted “Method of stamping and pulsed processing of liquid metal -“ Pulse volume stamping ”(RU 2194595, C2 7B 22D 18/02, 03.2000). The melt is produced in a melted billet, which is then moved into the die, and the die, in turn, moves towards the workpiece until it is in full contact, after which the melt is subjected to gas pressure, pressing and forging pressure through a punch. This analogue allows you to process any metals, including refractory and chemically active.

 [2]. The closest technical solution, as a prototype, is the invention “A method and apparatus for liquid stamping for casting chemically active metals using the method of induction retention of the melt” (RU2353470, C2 B22D 18/02, 07.2004).

 The objective of the invention is to increase the efficiency of use and expand technical capabilities by obtaining monolithic or composite parts of the most complex form with a fine-grained or amorphous structure, having high physical and mechanical properties.

The problem is achieved in that the known method of liquid forging is that the molten metal is obtained by melting the workpiece due to the electromagnetic field of the inductor with holding the side the surface of the melt on the punch and then moving it at high speed to a stamp, where the melt crystallizes in the volume of the part under excess pressure of the punch, characterized in that in addition to the action of the punch, the body of the part is affected by an additional pressure impulse created by the shock wave arising from the collision of a solid body introducing an additional punch into the metal - a needle moving at a higher speed and creating a higher pressure on the metal, which allows the injection molding process to transfer to the stage of crystallization of metal under pressure, an additional pressure impulse acts on the body of the part in the stamp, created by the shock wave that occurs when the detonation of an explosive is in direct contact with the needle introduced into the body of the part, which allows the process of crystallization of metal under pressure to be transferred to the stage metal processing, acceleration of the stamp, punch and needle can be carried out under the action of a shock wave created by an explosive, which allows the production of parts with Enven phase composition. The method can carry out the process of pulsed volumetric stamping, allowing at the first stage, when moving and filling with the melt, the die to supercool it by a predetermined amount, and in the second stage to compress the metal in the stamp to a predetermined value, as a result of which the part is formed from a fine-grained structure with a phase composition not characteristic of conventional metal forming. The liquid forging device comprises clutches, rods, a stamp, a punch, pipes, a sliding frame, tracking sensors, a vacuum melting chamber, a needle, a hammer, an inductor, a remelted billet mounted on a punch, after receiving the melt, the punch moves the melt into the die pressing chamber, and the stamp moves to the punch meeting, accelerated by gas pressure, characterized in that the additional pressure on the body of the part in the stamp is created due to the accelerated striker hit on a needle embedded in a metal. The stamp can be accelerated under its own weight by disconnecting the clutch from the rod, and at the time of the collision of the stamp and punch, the frames are fixed on the rods using clutches, the clutch moment is determined by tracking sensors, the vertically moving stamp and punch are sealed with corrugated pipes that are attached to a vacuum chamber, allowing the mechanisms to move and hold the vacuum inside the melting chamber. There can be several needles embedded in the body of the part, which are driven by the impact of the striker or explosive placed on the needle, the melting of the remelted workpiece is achieved by simultaneously melting the inductor and the electron beam produced by an electron gun or electron guns) mounted on in a vacuum chamber, reinforcement of metal or nonmetal is installed in the die cavity before forging, which, after being filled with the melt under the action of a needle, is combined into a composite part.

 The proposed method implements the installation shown in figure 1. The installation includes a melting chamber 1, where the cooled inductor 2 is placed, in which the remelted billet 3 is installed on the cooled punch 4. The inductor can be single-turn or multi-turn, as well as with separate power supply for the turns. The remelted preform is melted by the inductor from the lateral plane until the entire preform is melted. The inductor covers the molten metal in such a way that it is able to retain its side surface due to the electromagnetic field.

 [3]. The electromagnetic pressure on the metal (Pa) with a pronounced surface effect of the penetration of the field into the metal is expressed by the formula:

sm * H ^2/4, where H is the amplitude of the magnetic field component on the metal surface, A / m A piece of metal that is opaque to the field experiences pressure from the field, proportional to the square of the magnetic field at its surface, independent of the frequency of the field. Therefore, the same force action on the metal is carried out under the condition of the same current in the inductor. The higher the frequency of the current, the greater the voltage that must be applied to the inductor to ensure the same field strength.

 On the axis of the punch, a stamp 5 is installed at a certain distance over the workpiece in a housing of the upper movable frame 6, which is held by the upper clutch 7 on the mounting posts 8 mounted on the base plate 9. A pneumatic cylinder 10 with a piston-ttttok 11 is installed on the base plate, which pushes the lower a movable frame 12 provided with lower clutches 13. A punch 4 is mounted on the lower frame and water cooling passes through it into the punch. In the melting chamber 1, rigidly mounted on the mounting posts 8, a vacuum is created, which is held by the lower bellows 14 and the upper bellows 15.

The upper movable frame may begin to move downward under the influence of gravity when the upper clutch is pressed from the rods. Power cylinders 16 are rigidly fixed on the upper frame, and accelerating pistons 17 are placed inside them, due to which the movement of the upper frame can be accelerated by supplying gas under high pressure to the cylinders by opening the accelerating valves 18. The piston rod 11 moves upward under the influence of gas due to opening the lift valve 19. After the main volume of the workpiece is melted due to the electromagnetic field of the inductor, the crucible sleeve 20, sliding along the punch by the lever 21, rises and closes the space between the inductor rum and melt. The melt is inside the crucible bushings, then the punch together with the melt and the sleeve begin to move up, and the stamp down. Above the upper plane of the inductor, a collision of the crucible sleeve and the stamp occurs. The sleeve moves down, and the punch continues to push the molten metal into the pressing chamber 22 of the stamp. In the pressing chamber, the melt is compressed and begins to rapidly fill the internal cavity of the part 23. When the inner space of the stamp is completely filled with the melt, the needle 24, which acts as the upper punch, begins to move downward, compressing the melt and the crystallizing metal, deforming its structure and providing additional compression of the plane details to the plane of the stamp. The needle begins to move in a pulsed mode under the action of the striker 25, accelerated by gas by opening the upper valve 26. The striker accelerates in the cylinder 27, which is rigidly fixed to the upper frame and, striking the needle, transmits a force impulse to the part.

 After the body of the part is formed and the metal is cooled, the punch 4 drops down under the action of gas pressure acting on the piston rod, when the side valve 28 is opened, the lift valve 19 is opened to release gas from under the piston.

 When you open the top cover 30 on the melting chamber, it is possible to remove the stamp from the installation to remove the part. It is possible to remove the stamp with the part together with the upper frame, lifting them up and removing them from the installation using the cables 29. Reassembling the units is carried out in the reverse order.

On figa shows the time of melting of the workpiece, on figb - the moment of filling the die with a melt, which is fixed by tracking sensors, reading the data of which according to a given ACS program, additional metal processing is performed, shown in figv - the moment of the pulse insertion of the needle into the metal of the part . The method is called liquid forging, in view of the need to act on the metal melt at a very high speed to fill the thin-walled cavities of parts of complex shape, and the double forging action is necessary to process the metal by pressure directly in the stamp in order to achieve high physicomechanical properties of the part, which can be achieved conventional casting and deformation methods are not possible.

 To assess the forces acting during double forging on the metal of a part, we give an example of a calculation where titanium is used as a workpiece material, with a diameter of 120 mm, a height of 60 mm, and a weight of Зкг.

 The punch system, which moves from bottom to top and consisting of a cooled punch, a lower frame, a piston rod and a workpiece, has a total mass of 600 kg mi.

 The piston rod has a diameter of 400 mm.

 The stamping system, which moves from top to bottom and consisting of a stamp, upper frame and other mechanisms, has a total mass of 500 kg m2.

 Accelerating pistons have a diameter of 60 mm, a firing pin with a diameter of 200 mm has a mass of 10 kg and moves to collide with a needle weighing 5 kg, passing a distance of 300 mm.

 The needle is in contact with the metal, with a diameter of 12 mm, moves into the metal by 5 mm.

 The molten workpiece, leaving the inductor, moves upward by 150mm, and the stamp moves downward by 500mm. As a part, a bar with a diameter of 12 mm, a length of 4 m, and a mass of 2 kg will be manufactured.

[4] According to the law of conservation of momentum, the momentum of a closed system of bodies is kept constant. In this case, if m _/ - the mass of the punch at the moment of collision had velocity Vi, then its momentum mi * Vi, and accordingly the momentum of the stamp m2 * V2, then the total momentum of the stamp and punch before the impact is mi * Vi + m2 * V2. After the collision is complete the momentum will be equal to mi * V '+ m2 * V, regardless of what the velocities and masses of the collision bodies are equal, and whether the collision was frontal or not. It follows that if the impulse of, for example, the stamp decreases by a certain amount, then the piston momentum will increase by the same amount. In a fully elastic collision, and if the masses of the piston and the stamp are equal, after the collision, the stamp and piston will fly in opposite directions, at the same speeds. In the case of metal forging, it is necessary to choose a mode in which the stamp and punch begin to diverge after the part is formed. That is, so that the main impact energy is used to move the melt into the die cavity and to create pressure on the crystallizing metal.

 For classical injection molding, the mold filling time can be reduced to 0.1 seconds, and the inlet flow speed can reach 100m / s. This contributes to the high-quality relief design of castings of complex configuration. In addition, on the formation of the part, in classical injection molding, the pressure and the duration of the prepress after filling the mold have a significant effect. The pressing is carried out by several punches of small diameter, which are pressed into the body of the part by hydraulic pistons with a relatively low speed of 0, 1 ^ 0.5 mm / sec.

When implementing the proposed method, it is necessary to provide a higher stamp filling speed and metal processing in the stamp by pulse pressure. After the termination of the first pressure pulse, it is immediately possible to provide an additional pressure pulse, which creates a fine-grained or amorphous structure in the body of the part. To do this, it is necessary to monitor the time of filling the stamp with special sensors, which can record both mechanical movement of the melt and water hammer. At the end of the first pulse pressure, a second pulse acts on the metal through the needle, which exerts stronger pressure on the metal. The pressure generated by the action of the needle may exceed the pressure from the action of the piston by several orders of magnitude. To prevent the discrepancy between the stamp and the piston, it is necessary to fix them on the rods using clutches and after that it is possible to influence the melt with additional pulse pressure.

 The sequence of the method will be as follows: obtaining a melt due to induction melting of the workpiece; retention of the melt at the end of the punch due to the electromagnetic field of the inductor; raising the crucible sleeve, protecting the melt from spreading during the lifting of the punch from the inductor; ensuring movement of the stamp and the punch to meet each other before the collision, under the action of which the melt enters the stamp until it is completely filled, causing a water hammer inside the melt; immediately after water hammer, the impact on the melt with additional pulse pressure due to the impact of the needle on the metal in the stamp.

 We calculate the momentum of the force that the molten metal will experience if a stamp falls on it under its own weight, weighing 500 kg from a height of 0.5 m.

 [4] Impulse (momentum): P = m * v,

where t is the mass, kg; v - speed, m / s.

 The center of mass moves by 40 mm during the collision. The speed of free fall of the stamp at the moment of contact with the melt will be:

 Vi = 2g * 0.5M = 3.13m / s.

 The force impulse acting on the stamp and the molten metal is equal to the change in momentum:

J = Dr = pi p ₂ = 0 (500kg) * (3, 13m / s) = -1565N * s.

Before stopping, the center of mass slows down from a speed of 3.13 m / s to zero and passes a distance h = 40 mm, while the average compression speed the melt will be equal to Ang = 1.57 m / s, and the collision time will be At = h / V2 = 0.025 sec. In this case, the force acting on the melt will be equal to:

 F = J / t = 1565N * sec / 0.025sec = 62.6kN.

The diameter of the pressing chamber, where the liquid melt enters, is 120 mm and its area is S = xL ² = x * (6 * 10 ² ) ² m ² = 1.13 * 10 ² m ² .

Therefore, the pressure that the stamp creates when falling on the melt reaches:

P = 62, 6kN / 1.13 * 10 ² m ² = 55.4 * 10 ⁵ Pa.

 That is, it reaches 55.4 atmospheres.

 The melt will fill the die cavity, made in the form of a rod with a diameter of 12 mm, a length of 4 m with an average speed of 157 m / s, for a time of 0.025 sec.

If the stamp begins to fall down not only under the action of gravity, but also under the influence of gas pressure equal to, for example, 5 atm. (~ 5 * 10 ⁵ Pa), which acts on two accelerating pistons with a diameter of 60 mm with a total area of 2.26 * 10 ^{~ 2} m ² , the additional force F ₂ will be:

F ₂ = P * S = 5 * 10 ⁵ Pa * 2.26 * 10- ² m ² = 11.3 * 10 ³ N.

 Thus, the force acting on the melt will increase by 18%.

If the pressure in the accelerating pistons is increased to 50 atm, then the action of gravity can be neglected, while the force F ₃ acting on the pistons will be 11 ZKN. The acceleration time of the mass of 500 kg will be:

t _{3 =} t ^ h / F

t _{3 =} ^ 500kg * 0.5m / 113 * 1 (FH = 0.047sec.

 The speed of the stamp during contact with the metal will be equal to:

 V3 = 0.5m / 0.047 sec. = 10.6m / sec.

 The force impulse acting on the stamp and the molten metal in this case is equal to:

J ₃ = 500kg * 10.6m / s = 5300N * s.

 The average collision speed At 4 = 5,3m / sec.

Impact time \ g ₇ = 4 * 10 ² m / 5.3 m / s = 0.0075 sec.

The average resulting force will be equal to: F _{4 =} 5300 N * s / 0.0075 s = 707 kN.

 The pressure will reach:

P ₄ = 707 * 10 ³ N / 1.13 * 10 ² m ² = 799 * 10 ⁵ Pa

In this case, the pressure reaches 800 atmospheres. At such a high pressure, the metal receives a very high acceleration, which contributes to a good form filling of the stamp. With such a collision, the flow rate of the metal in the stamp reaches 530 m / s., The filling time of the stamp does not exceed 7.5 * 10 ³ sec.

 The proposed method, in addition to the forces created by the stamp system, additionally affects the melt due to the accelerated upward movement of the punch system. If, for example, the force impulse acting on the molten metal from the side of the punch is equal to 5300 N * s, then from the side of the punch it should be approximately the same. The mass of the stamp system is 600 kg, the diameter of the port-ttttok is 400 mm, the pressure on the piston is 50 at., And the distance to the impact with the stamp is 150 mm.

The force F ₅ acting on the piston is equal to:

F ₅ = P ₅ * S ₅ = 50 * 1 About ⁵ Pa * 0, 126m ² = 628kN.

 Punch travel time: ts = ^ ms * hs / Fs

ts = \ 600kg * 0, 15m 628kI = 0.014sec.

 The speed of the punch will be equal to:

 Vs = 0.15m / 0.014sec = 10.7m / s.

 The force impulse acting on the melt is equal to:

/ ₅ = 600kg * 10, 7 'm / s = 6420N * s.

 Given the force of gravity, the impulses of the force of the punch and punch will be approximately equal, so the pressure on the melt during their collision will reach 1600am. and the melt flow rate in the stamp will exceed 1000 m / s.

The above calculations show the possibilities of the proposed method using pulsed pressure. The method allows in a very a wide range to select the necessary pressure on the molten metal to obtain high-quality parts.

[5] To prevent the rebound of the stamp and punch, as well as to impact the crystallizing metal with additional shock pressure, clutches (mechanical or magnetic) are used that fix the frames to the mounting posts. After the action of the impulse pushing the melt into the die cavity, a second impulse (water hammer) occurs. The pulses acting on the metal can be fixed with special seismic sensors, as well as sensors that fix the position of the melt in the stamp. Based on the readings of these sensors, the moment of final forging of the metal in the stamp is determined, immediately at the moment the melt stops in the stamp, additional shock pressure through the needle begins to act. The time period from the moment the die is filled with the melt to the moment the needle begins to move is in the range of 0.1 sec. up to 1 * 10 ⁹ sec., in other words, this period of time tends to zero. [6] This additional final pressure is intended to finally mint the plane of the part along the plane of the stamp, and is also intended to ensure the deformation of crystallizing metal.

 [7] At high stamp filling speeds, it is possible to melt the most complex part shapes. If the time for filling the stamp with metal is in the range of 0.1 to 0.001 sec, therefore, the time for introducing the needle into the body of the part should take a shorter period and should be respectively in the range from 0.01 to 0.0001 sec. After the stamp was filled with the melt and a water shock occurred, the metal immediately at the same moment must be applied through the needle with additional finishing pressure.

For example, a striker with a diameter of 200 mm and a mass of 10 kg is accelerated by gas pressure in South Oat. before impact with the needle at a distance of 300mm. Needle 5kg weighs 5mm into the body of the part. We calculate the momentum of the force acting on the metal. The strength of the _Fe, acting on the firing pin is:

F ₆ = P ₆ * S ₆ = 100 * 10 ⁵ Pa * 0.03m ² = 314kN.

 Time of movement of the striker:

G _{b = V} / 0kg * 0, Зм 314кН = 0.03 sec.

 The speed of the striker will be equal to:

V ₆ = 0.3m / 0.03 s = 10m / s.

 In an elastic collision, the needle’s speed will be 20 m / s, since, according to the law of conservation of momentum, its mass is two times less than the mass of the striker. The force impulse acting on the metal of the part is equal to:

b ₌ 5kg * 20m / s = 100N * s.

 At a distance of 5mm, the needle speed drops to zero, so the average needle speed in the metal is 10m / s. Therefore, the collision time (the time of the introduction of the needle into the body of the part) is 0.0005 sec, and the force acting on the metal reaches: 1 UN * sec / 0, 0005 sec = 200 kN.

 With a needle diameter of 12 mm, the pressure on the metal reaches:

200kN / 113 * 10 ⁶ m ² = 1.8 * 10 ⁹ Pa.

 This value is close to the tensile strength of many high-strength alloys.

 [8] On figa, b, c shows a schematic diagram of the operation of the device, where the mechanisms for the forging of the melt is driven by the supply of gas to the pistons. [9] In Fig. Za, b, c it is shown that speed and pressure can be enhanced by exposing the pistons and especially the needle to explosive (detonation) pressure.

In order to act through the needle on the metal even more pressure, it is possible to use explosives (BB), which are placed directly on the needle. Explosives can transmit pressure equal to several tens of GPa through a needle. [10] At such pressures, phase transitions and chemical reactions can occur in metals. In practice, after the passage of the shock wave, the formation of, for example, zinc ferrite, titanium carbide, tungsten carbide, barium titanate. In this way, it is possible to produce parts from superconducting materials, as well as to synthesize materials containing diamond, carbide or boron nitride.

 [9] Shock waves arise upon the collision of solids or upon detonation of explosives.

The speed of the substance is Vo. Over a period of time At = I / C2, the projectile will pass the path DZ = V ₍ \ t = (Vo * l) / co. The sample under the influence of the projectile will decrease by the length of this path (DZ), and therefore, its compression will be e = - A1Д = - Vo / co. The sample will now behave like a compressed spring, and its free right end will unload so that the free surface will move to the right at a speed of 2 Vo, and the unloading wave will go to the left at a speed of co. The acceleration phase lasted t = 21 / co, and the value of shock compression e = Vo / co.

For example, we determine what value the elastic stress of a steel bar reaches when it is struck by a body flying at a speed of Vo = 20 m / s. The modulus of elasticity of steel is E = 210,000 N / mm, the shock compression will be e = - 0.4%, the elastic stress s = eE = 840 N / mm ² . The waves arising from such a not very strong impact can reach an intensity exceeding the elastic limit.

 [9] For substances, transformations of crystal lattices caused by the action of shock waves, the formation of dislocations and point defects with the subsequent formation of twins with increasing pressure can occur, and phase transitions occur at very high dynamic pressures.

 According to Holtzman and Cowan, the deformation at the front of the shock wave is equal to:

e = (2/3) In (Vi / V ₀ ) (1) For example, if a shock wave with an intensity of 10 GPa propagates in iron, then this pressure corresponds to a compression of 5% of the initial volume, i.e. Vi = 0.95 * Vo. According to equation (1), this deformation corresponds to plastic deformation e = - 3.4%, where the tensile speed of the material is έ = 34 10 ⁶ s ¹ .

 The sizes of crystals that have arisen after shock-wave loading are significantly smaller than in the case of deformation carried out by traditional methods; accordingly, the hardness and strength of the material are higher.

 Under the action of shock waves, a number of substances undergo one or several phase transformations. At a pressure of 13 GPa in the iron, a → b transition occurs — a transition. At pressures exceeding 20 GPa in titanium, an abrupt increase in strength was established, which is due to a -> b - the transformation of Ti. During explosive pressing, due to the heating of the metal, its compression is achieved with a smaller amount of explosive. The maximum density is higher, which makes it possible to reduce the negative effect of the unloading wave.

 [9] On the Hugoniot Curve, it is presented that the heated powder, even at low pressures, approaches the curve for a solid. In addition, the increase in internal energy during hot pressing is less than that during cold pressing. The proposed method will achieve high efficiency due to the fact that the stamp is processing heated metal or a melt, which, being deformed due to shock waves, acquires a special structure with high specific strength.

In Fig. 3a, a variant of the device is shown where the needle is inserted into the body of the part under the influence of an explosive shock wave (EX). Explosive 31 is placed on the upper end of the needle, the detonator 32 launches a shock wave under the action of an electric supply 33, where the moment of the explosion is determined by a computer program controlled by readings of tracking sensors. [10] The magnitudes of the pressure pulses depend on the size d of the explosive, which determines the length of the detonation pressure section and is equal to the length of time during which each point experiences the same pressure. The thicker the explosive layer, the longer the constant pressure will remain at each point on the surface and the greater the pressure pulse will be, although the magnitude of this pressure does not depend on the thickness of the explosive layer. In the theory of elasticity it is shown that the stress s in the direction of wave propagation is determined by the expression:

a = Q * Ci * V _b

where r is the initial density of the material;

 Vi is the particle velocity;

C _{l -} wave velocity.

 [11] The proposed method for industry can practically implement the method of pulsed die forging, theoretically developed in 1994.

 The basis of this technology is the ability of the melts to remain in a liquid state below the theoretical melting temperature, which is proved and justified by the theory of the production of amorphous metals, on the basis of which it is possible to calculate the melt supercooling required in this case; another part of the technology is based on the ability of supercooled melts to transform into a solid state under high pressure under the influence of pressure.

[11] In order for the metal to pass into the solid phase from exposure to pressure and not to transfer to the melt, after removing this pressure, it is required that the amount of heat Q _p , the metal lost by the melt during its transportation to the stamp and being in the stamp during its compression and final filling of the die cavities, it exceeded the amount of heat Q _Kp ,, released by the metal during its crystallization. From this condition, it is possible to calculate the degree of supercooling of the melt dT, upon reaching which the crystallization time tends to zero:

Q = c * t * 3G;

Q = m * q _K ;

dT = q _K / s,

where c is the specific heat of metal;

 t is the mass of crystallized metal;

q _K is the specific heat of crystallization of the metal.

 So, for example, for Ti, the supercooling temperature dT, at which the crystallization time dG – 10, is:

dT = q _K / c = (392 kJ / kg) / (0.33 kJ / (kg ° C)) = 739 ° C.

The amount of heat of dissipation Q _p lost by the liquid phase of the metal is calculated by the formula:

Q _P - L -q _r -St,

where A is the surface area of the cooled substrate in contact with the molten metal, m ²

q _r - specific heat flux, W / m ² ,

dί is the contact time of the liquid phase of the metal and the substrate, sec.

dί = a · DT,

where a is the contact heat transfer coefficient;

 AT is the temperature difference between the melt and the substrate.

 Another important parameter determining the feasibility of the IOS process and affecting phase transformations in metals is pressure.

An increase in the solidification temperature with increasing pressure is observed in those metals that occupy a smaller volume in the solid state than in the liquid state. To transfer a liquid metal to a solid state, an impact on the melt of pressure of a value of P, which compresses the melt to a density x corresponding to the solid state state near the melting temperature T _s .

 So, for example, to transfer molten Ti to the solid phase near its melting temperature, compression by x = 1% is necessary.

 The required value of melt compression can be determined according to the theory of compression by shock waves:

4 = ( ^y ,: Co) - 100%,

where y _in is the compression rate of the substance;

 Co is the propagation velocity of a longitudinal wave in a substance.

 From here, the required collision rate of the melt with the walls of the die cavities can be calculated:

n _b = x · Co / 100%.

So, for example, to transfer the Ti melt, which is at the melting temperature T _s , into a solid state, it is necessary to compress the metal due to the collision of the melt and the stamp with a velocity of y ₌ 27 m / s.

 The compression time of the body by shock pressure is:

St _s - 21 / Co

where / is the length of the body.

At I = 0.5 m for Ti we have St _c = 7.4 · PU ⁴ sec.

 From the above example it follows that the time of applying pressure P to the melt is so short that only very small crystals have time to form. Moreover, the intercrystalline space formed by reducing the volume of the metal upon its transition into the crystal is continuously filled by means of forced compression.

In Fig. Za, the moment of metal melting is shown, in Fig. Zb, the forging of metal is shown, under which the die is filled and immediately after that there is a shock wave under the influence of detonation of the explosive mounted on the needle, in Fig. Зv the final moment of forging under the action is shown introducing the needle into the body of the part. Fig. 3 shows a device that in practice can carry out the process of pulse volumetric stamping (IOS) due to which it is possible to produce parts having a very high specific strength. Using explosives, it is possible to apply a pressure pulse exceeding 30 GPa to the melt that has filled the stamp through the needle. Under the influence of such pressures, the metal is deformed directly in the stamp, which can be compressed by 5% or more. [3] An additional effect is achieved by using electron-beam heating of the billet, due to electron-beam guns (EBLs) mounted on a vacuum casing and shown in Fig. Za.

As is known, induction heating does not allow metal to float with a melting point above ~ 2000 ° C. Fig. 3a shows electron beam guns 34, which electron beam 35 melt the workpiece together with the inductor. The choice of electron beam melting is associated with the fact that it is produced in a deep vacuum, if, for example, using plasma working in gas instead of it, the technological process of forming the part will be disrupted, since the gas will prevent filling of the die cavity. Using electron beam and induction melting at the same time, it is possible to melt such metals as niobium, molybdenum, tantalum, tungsten, as well as their refractory alloys and compounds. In this design, the installation will allow the production of refractory metals, for example, rocket nozzles, turbine blades or shell for rockets. The effect of the implementation of the method can be enhanced by the production of composite parts. In Fig. 3a, a reinforcement 36 is placed in the die cavity, which may be made of carbon-carbon fibers, carbon-fiber crystals, silicon oxide fibers, boron nitride, or simply metal reinforcement. High pressures during forging allow the melt to completely fill all the die cavities together with the fittings (Fig. Zb), which shows the exhaust gases 37 BB from detonation. Additional forging due to the needle (Fig. Sv) allows you to combine crystallizing melt and reinforcing material into a monolith, producing composite part 38 at the output.

 Thus, the proposed method allows you to create parts from compositions of metals and non-metals, the so-called cermet.

 In connection with the foregoing, the method may be useful in the production of particularly complex and expensive parts for civilian and military products

LITERATURE

[1]. Volkov A.E. - Patent of the Russian Federation, RU 2194595 - Method of stamping and pulsed processing of liquid metal - “Pulse volume stamping”, C2 7B22D 18/02, 03/10/2012.

 [2]. Volkov A.E. - Patent N ° 2353470, - Method and device for liquid stamping for casting chemically active metals using the method of induction retention of the melt, C2 B22D 18/02, 02.07.2004.

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Claims

CLAIM 1. The method of liquid forging, which consists in the fact that the molten metal is obtained by melting the workpiece due to the electromagnetic field of the inductor with holding the side surface of the melt on the punch and then moving it at high speed into the stamp, where the melt crystallizes in the volume of the part under excess pressure of the punch , characterized in that the body of the part in addition to the action of the punch is affected by an additional pressure impulse created by the shock wave arising from the collision of a solid body, introducing an additional punch is inserted into the metal - a needle moving at a higher speed and creating a higher pressure on the metal, which allows the injection molding process to be transferred to the stage of crystallization of the metal under pressure.  2. The method according to claim 1, characterized in that the body of the part in the stamp is affected by an additional pressure impulse created by the shock wave arising from the detonation of an explosive in direct contact with the needle introduced into the body of the part, which allows the process of crystallization of metal under pressure, transfer to the stage of metal forming.  3. The method according to claim 1., Characterized in that the acceleration of the stamp, punch and needle can be carried out under the action of a shock wave created by an explosive, which allows you to produce a part with a modified phase composition. 4. The method according to claim 1., Characterized in that it can carry out the process of pulse volumetric stamping, allowing at the first stage when moving and filling the melt stamp, supercool it to a predetermined value, and in the second stage to compress the metal in the stamp to a predetermined value, as a result of which the part is formed from a fine-grained structure, with a phase composition not characteristic of conventional metal processing by pressure.  5. A liquid forging device containing clutches, rods, a stamp, a punch, pipes, a sliding frame, tracking sensors, a vacuum melting chamber, a needle, a firing pin, an inductor, a remelted billet mounted on a punch, after receiving the melt, the punch moves the melt into the pressing chamber stamp, and the stamp moves to the meeting of the punch, accelerated by gas pressure, characterized in that the additional pressure on the body of the part in the stamp is created due to the accelerated striker striking the needle embedded in the metal.  6. The device according to claim 5., characterized in that the stamp can be accelerated under its own weight by disconnecting the clutch from the rod, and at the time of the collision of the stamp and the punch, the frames are fixed on the rods using clutches, the clutch moment is determined by tracking sensors.  7. The device according to claim 5., characterized in that the vertically moving stamp and punch are sealed with corrugated pipes that are attached to the vacuum chamber, allowing the mechanisms to move and hold the vacuum inside the melting chamber.  8. The device according to claim 5., Characterized in that the needles embedded in the body of the part may be several, which are actuated by impact of the striker or explosive applied to the needle. 9. The device according to claim 5., Characterized in that the melting of the remelted workpiece is achieved by simultaneously melting the inductor and the electron beam produced by electronic gun or electron guns) mounted on a vacuum chamber. The device according to claim 5, characterized in that a reinforcement of metal or nonmetal is installed in the die cavity before forging, which, after being filled with the melt under the action of a needle, is combined into a composite part.