RU2179491C2 - Method for making blanks of missile bodies - Google Patents

Abstract

FIELD: plastic metal working, namely processes for forming blanks of missile bodies. SUBSTANCE: method for making missile body by extruding steel blank in die by means of punch comprises steps of forward extrusion by plunger at punch rigidly mounted along axis of die; at extrusion process providing gap between outer surface of formed blank and inner surface of die; keeping said gap at extrusion process; then drawing blank through annular dies for subsequent mechanical working of its outer surface and reduction of head portion of missile body. Preferably, blank of easy-to-form material such as low-carbon steel before forward extrusion and reduction of head portion of missile body is heated up to deforming temperature. Preferably, blank of easy-to-form material such as low-carbon steel is subjected to forward extrusion and to reduction of body head at 20C. EFFECT: enhanced accuracy of missile body blanks without mechanical working of lock. 3 cl, 6 dwg

Description

 The invention relates to the field of metal forming, and more particularly to methods of stamping blanks shell shells.

 A known method of manufacturing blanks shell shells by extrusion. The billet from the metallurgical semi-finished product is placed in the matrix, the movable punch is immersed in the billet, squeezing the metal in the opposite direction (towards the punch). The method is applicable for both cold and hot stamping. In the latter case, before stamping, the workpiece is heated to a deformation temperature. A modification of the method of hot stamping by reverse extrusion using a square billet, known as the Ergardt method, is widely used in domestic shell production in the manufacture of shells of medium and large caliber shells from standard projectile steels C60 and 45X1 (A. Rybarg Shell production. M. : Oborongiz, 1943, pp. 112-114).

 The disadvantage of this method is the possibility of displacement of the axis of the movable punch relative to the axis of the matrix due to wear of the movable joints, uneven heating of the workpiece, and other factors that lead to significant eccentricity of the body chamber relative to its outer surface during stamping, i.e. to increase the difference and imbalance of the body. This drawback becomes especially noticeable for thin-walled shells of modern high-explosive fragmentation shells with a high explosive filling ratio.

 This drawback is largely eliminated by using the direct extrusion method (Forging and stamping. Handbook in 4 volumes, red. Advice: EI Semenov (chairman) and others M: Mashinostroenie, 1985, v. 2, p. 214; A.I. Kapustin. Stamping of forgings of the glass type, M .: NPO Temp, 1991, pp. 28-95). In this method, the die and punch are rigidly bonded to each other during extrusion, the workpiece is squeezed out using a press stamp into the gap between the die and the punch. However, this increases the contact time of the heated workpiece with the stamping tool.

 Closest to the proposed method for the manufacture of shell blanks is a method comprising extruding a steel blank in a matrix using a punch (GB 1508532 A, MPK-3 V 21 K 21/06, 04/26/07).

 The objective of the invention is to provide a method for the manufacture of blanks of shell shells, which eliminates intensive heat removal from the blank, maintains the optimal temperature regime during extrusion and reduces the anisotropy of the structure and properties of the metal in the blank of the shell shell.

 The solution of the problem lies in the fact that in the manufacture of shell shells, including extruding a steel billet in the matrix using a punch, according to the invention, direct extrusion is performed by a press stamp, in which the punch is rigidly fixed along the axis of the matrix, and during extrusion between the outer surface of the stamped billet and the inner surface of the matrix to form a gap that is maintained during the extrusion process, and then carry out the hood with thinning through the ring matrix with subsequent mechanical cal treatment outer surface and crimping the head portion of the housing.

 Preferably, the steel billet is heated to a deformation temperature before direct extrusion and crimping of the head.

 Preferably, a preform of easily deformable material, for example, low carbon steel, is subjected to direct extrusion and crimping of the head at room temperature.

 The technical result that is obtained by carrying out the invention is that as a result of its use, shell blanks with a difference of less than 1 mm, a metal utilization factor (CMM) of more than 0.65 and dimensional accuracy of the inner chamber according to the 5th class of engineering tolerances are obtained .

The invention is illustrated by drawings, where:
figure 1 shows a diagram of the proposed method of direct extrusion,
FIG. 2 - the General sequence of operations for the manufacture of shell shell,
figure 3 - the microstructure of the metal in various sections along the height of the housing,
figure 4 - distribution of hardness in various sections along the height of the housing,
5 is a workpiece housing with a diaphragm,
Fig.6 - dependence of the ratio of thickness to the height of the wall of the stamping when extruding the workpiece housing from the ratio of the initial temperatures of the tool and the workpiece.

 The method is as follows (figure 1).

 The steel billet 1 is heated to a temperature of hot deformation of the metal by high-frequency currents (or in another way), after which the heated billet is introduced into the inlet part of the matrix 2. The billet is deformed by the axial force of the press stamp 3. In the process of extrusion between the outer surface of the workpiece and the inner surface of the matrix 2 form a gap that is maintained during extrusion. The presence of a gap A between the outer surface of the workpiece and the inner surface of the matrix ensures the preservation of the temperature of the workpiece during the stamping process and the formation of a favorable metal structure. In addition, the absence of friction on the outer surface reduces the force on the press stamp, which allows the use of presses of lower power.

 Subsequently, the press stamp and the matrix are retracted upward, and then, by the axial movement of the puller 4, the shell blank is removed from the stationary punch.

Using the proposed method, blanks of a shell shell of 100 mm high-explosive fragmentation shell were made of high-fragmented eutectoid steel 80G2S. The billet was heated to a temperature of 1000-1050 ^o With a speed of 0.35 mm / s high-frequency currents. Stamping was carried out on a hydraulic press with a force of 400 tons. The difference between the shell blanks did not exceed 0.8 mm.

 After the operation of direct extrusion of the shell shell blank, it was drawn out with thinning through the ring matrices, preliminary machining of the outer surface of the shell shell blank, and hot crimping of the head part were performed. The indicated sequence of operations made it possible to reduce the coefficient of variation V of the static dispersion of the shell mass to V = 0.0015 (V = σ / Q, σ is the standard deviation of the mass, Q is the average sample mass of the shell) corresponding to the dispersion of the mass within the zero weight sign ( ± 1/3%).

 The study of the mechanical properties of the metal cut from the wall of the workpieces of the bodies for various operations of manufacturing the body (figure 2), metallographic studies of the samples (figure 3) and the determination of hardness along the length of the body (figure 4) showed that the proposed method of direct extrusion with additional operations to obtain shell blanks provides a homogeneous metal structure along the entire length of the shell.

 The heat transferred from the heated billet to the stamp elements in contact with it (die, punch) is removed using cooling water. In this case, the heat sink intensity is selected from the conditions of optimality of the ratio of the thickness of the extruded cup to the height of its wall (Fig.6).

 The proposed method of manufacturing shell shell blanks was also used for the manufacture of shell shells with a diaphragm (with an H-shaped longitudinal section) (Fig. 5).

 Using the proposed method, standard 12 fragmentation mock-ups (⌀ 60 mm, N - 200 mm) were made from easily deformable carbon steels St15 and St11YuA. Direct extrusion was carried out at room temperature on a crank press with a force of 315 i.e., while the preforms were phosphated and saponified before cold extrusion. After extrusion, extraction was carried out at room temperature through two ring matrices. All the internal and external dimensions of the part, with the exception of trimming along the end and threading, were obtained without machining.

 The method can be used for the manufacture of shell shell blanks from both standard shell steel С60, 45Х1, and promising high-fragmentation steels 60Г2С, 80Г2С, 110Г2С, etc. In the latter case, the modes of hot deformation and heat treatment are selected in accordance with the thermokinetic diagram.

 The proposed method for the manufacture of blanks shell shells provides dimensional accuracy of the inner chamber of the shell 12-13 quality.

 The high accuracy of the workpiece manufacturing in the future allows, due to drawing operations, to obtain shell shells of large elongation that correspond to current trends in the development of artillery shells. The method provides a metal utilization coefficient (CMM) of more than 0.65, an uncultivated surface coefficient (KNI) of more than 0.45, a difference of less than 1 mm.

 The proposed method for the manufacture of shell shell blanks can be used to manufacture a wide range of shell blank shells for medium and large caliber artillery shells (high-explosive fragmentation shells, shaped-charge shells, high-explosive armor-piercing shells, cluster cartridges, etc.), small-caliber artillery shells made of low carbon steel automatic lines, barrel mines and recoilless shells, anti-personnel grenades under-barrel and automatic grenade launchers, fragmentation and fragmentation-shaped cartridges military combat elements of artillery shells, warheads of multiple launch rocket systems (MLRS), aviation cluster weapons and tactical missiles.

Claims (3)

 1. A method of manufacturing billets of shell shells, including extruding a steel billet in a matrix using a punch, characterized in that it is directly extruded by a stamp, in which the punch is rigidly fixed along the axis of the matrix, moreover, during extrusion between the outer surface of the stamped billet and the inner surface the matrices form a gap, which is maintained during the extrusion process, after which the hood is drawn with thinning through the ring matrices, followed by machining of the outer surface surface and compression of the head of the housing.  2. The method according to p. 1, characterized in that the steel billet is heated to a deformation temperature before direct extrusion and crimping of the head.  3. The method according to p. 1, characterized in that the workpiece from an easily deformable material, for example, from low carbon steel, is subjected to direct extrusion and crimping of the head part at room temperature.

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