RU2354483C1 - Vessel production method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method relates to pressurised treatment of metals and may be used for high pressure containers manufacturing from pipe shells. The method includes pipe cutting to sections, forming of bottom, hot turning of throat, mechanical treatment, cleaning of inner surface and thermal treatment, which will be due after throat turning but when bottom is not formed. After inner surface cleaning, the outer surface is to be cleaned. Then, the cylindrical surface of work piece is lubricated and treated to make walls thinner. The latter operation is performed in rolling-off machines, when items are cold. The end part of the work piece remains with the original thickness. After that, bottom is formed by squeezing end part of the work piece in the rolling-off machine.

EFFECT: reduced weight of container and reduced manpower effort during thermal treatment and cleaning, increased strength of item.

2 cl, 4 dwg

Description

The invention relates to the processing of metals by pressure and can be used in the manufacture of high pressure cylinders from tube blanks.

A known method of manufacturing cylinders, including cutting a pipe into measured billets, cleaning the inner surface, spraying an aluminum layer on the inner surface of the billet along its entire length during its rotation and axial movement, heating the ends of the billet for rolling, contact mechanical impact on the molten layer of aluminum at the ends of the billet a special tool, hot rolling of the neck and bottom and heat treatment of the cylinder (see ed. St. USSR No. 1750817, IPC B21D 51/24, announced July 23, 1990, published July 30, 92).

The disadvantage of this method is the high complexity of cleaning the inner surface of the cylinder after heat treatment through the hole in the neck.

The closest identified analogues selected for the prototype is a method for the production of vessels with spherical and cylindrical parts, as well as a neck from hollow billets with a bottom, including preliminary abrasive cleaning of the inner surface of the workpiece, shaping the neck until it is completely sealed, heat treatment, including hardening only cylindrical and spherical parts, machining the neck and final abrasive cleaning of the inner surface (see ed. St. USSR No. 1712045, IPC B21D 51/24, claimed 15.05.89, published 02.15.92).

The disadvantage of the prototype is also the high complexity of cleaning the inner surface of the cylinder after heat treatment through the hole in the neck. In addition, the cylinders made in this way have insufficient geometric accuracy, since during heat treatment of the cylinder after sealing the neck under the action of pressure of heated air, the balloon “inflates,” as it were, losing its geometry and also relatively low structural strength.

The problem solved by this invention is to provide a higher structural strength of the manufactured cylinders and reduce their mass.

To solve the problem in a method of manufacturing vessels, including the manufacture of a workpiece by cutting the pipe into measured billets, forming the bottom, hot rolling of the neck, its subsequent machining, cleaning the inner surface of the workpiece, heat treatment, including hardening and tempering, heat treatment is carried out after rolling the neck with an unformed bottom, and after cleaning the inner surface, the outer surface is cleaned, then grease is applied to the cylindrical surface the workpiece, after which the cylindrical part of the workpiece is processed by thinning the wall in the rolling tool in a cold state, leaving the end part of the workpiece with the original wall thickness, after which the bottom is formed by crimping the end part of the workpiece in the rolling tool.

In addition, at the points of transition of the cylindrical part of the vessel to the dome of the neck and bottom, conical or step thickenings can be made.

In the inventive method, the workpiece is subjected to heat treatment with a rolled neck and an unformed bottom, which reduces the complexity of cleaning the outer and inner surfaces of the workpiece before cold wall thinning. Since the thinning of the wall and the formation of the bottom is carried out in a cold state, there is no need for heat treatment of the cylinder and its subsequent cleaning. Moreover, in the process of cold deformation of the metal of the thermally hardened billet during the process of thinning the wall of the cylindrical part of the cylinder, the hardening effect occurs, which increases the structural strength of the cylinder and, accordingly, reduces the weight of the cylinder, and due to the formation of conical or step thickenings of transition sections at the junctions of the cylindrical section with the neck domes and the bottom reduces the risk of cylinder destruction in these hazardous areas during operation.

The essence of the proposed method is illustrated by the following drawings:

- figure 1 shows the original measured workpiece;

- figure 2 is a workpiece with rolled up and processed neck after heat treatment;

- figure 3 - blank after thinning the wall;

- figure 4 is a finished balloon.

The inventive method can be carried out as follows.

For the manufacture of cylinders from alloy steel 30XMA, GOST 4543-71, a pipe ⌀ 219 × 7, GOST 8372-70 was used. The pipe was cut into measuring blanks with a length of 1300 mm (Fig. 1) using a pipe-cutting machine. Then the inner surface of the measured blanks was machined with a metal brush on a lathe to remove rust and scale. Then, in the gas slit furnace, the end of the billet was heated to a temperature of 1150 ° С for rolling and subsequent rolling of the neck on the rolling machine. After that, the heat treatment of the obtained billet was carried out in shaft electric furnaces — quenching at a temperature of 850 ° C and tempering at a temperature of 570 ° C. Then, on a screw-cutting machine, the thread in the neck of W 27.8 was processed according to GOST 9009-81 (figure 2). Then, abrasive cleaning of the outer and inner surfaces of the workpiece was carried out, followed by phosphating of the cylindrical part of the workpiece and saponification. After that, using the P7836 SHO model press, the cylindrical part of the workpiece was processed by thinning the wall in the rolling matrix to a thickness of 4.5 mm, leaving the end part for the bottom with the original wall thickness. In this case, with the help of a punch, a conical transitional section was formed into the neck dome (Fig. 3). After that, the bottom was formed by crimping the end part in the rolling tool and a finished balloon (Fig. 4) 1650 mm long was obtained. The finished cylinder was tested according to traditional technology.

Thus, in comparison with the prototype, the inventive method allows to make more durable and lighter cylinders due to the hardening effect during cold deformation of the metal of the thermally hardened billet during thinning of the wall of the cylindrical part of the cylinder, as well as due to the formation of conical or step transition sections in the neck and bottom domes . In addition, the inventive method allows the use of workpieces of shorter length, which ultimately reduces the weight of the container, as well as the complexity of the heat treatment and cleaning.

Claims (2)

1. A method of manufacturing vessels, including the manufacture of a workpiece by cutting the pipe into measured workpieces, forming the bottom, hot rolling of the neck and its mechanical processing, heat treatment, including hardening and tempering, cleaning the inner surface of the workpiece, characterized in that the heat treatment is carried out after hot rolling the neck with an unformed bottom, and after cleaning the inner surface, the outer surface is cleaned, then grease is applied to the cylindrical surface of the workpiece, after why the cylindrical part of the workpiece is processed with the wall thinning in the rolling tool in the cold state, the end part of the workpiece with the original wall thickness is left, and then the bottom is formed by crimping the end part of the workpiece in the rolling tool. 2. The method according to claim 1, characterized in that at the points of transition of the cylindrical part of the vessel into the neck and bottom, conical or step thickenings are performed.

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