RU2258750C1 - Device for production of high-strength steel thin-walled circular articles of precision geometric sizes - Google Patents

Abstract

FIELD: mechanical engineering; heat treatment of steel articles.

SUBSTANCE: proposed device is provided with n-number of hollow mandrels made from austenite steel and set of spacers for separation of mandrels which are made in form of ring with encircling disk; outer diameter of rings is lesser than inner diameter of mandrels; some disks project beyond mandrels in some spacers or partially overlap mandrel end faces in other mandrels. Each mandrel is detachable and is made from two parts for mounting circular articles on mandrel; one part has one or several projecting stages and other part has inner stages engageable with outer stage of first part; slot is provided at joint area of mandrel parts for locking the circular articles by inner corrugation. Alternating design of components makes it possible to perform heat treatment of articles of simple and complex configuration.

EFFECT: enhanced stability of obtaining geometric sizes; improved quality of steel articles.

5 dwg

Description

The invention relates to mechanical engineering and can be used for heat treatment of steel products to obtain high strength characteristics in combination with the exact dimensions of thin-walled parts and containers.

A device is known, taken as a prototype, for producing high-strength steel thin-walled products of precise geometric dimensions in a heating device containing a hollow mandrel made of a material having a larger coefficient of linear expansion than the material of heat-treated ring products on the mandrel. The heating device is an induction heater and a stand on which a mandrel with a ring is mounted. Heating is carried out both by the external and internal field of the induction heater (see SU 245825, С 21 Д 9/40, 06/11/1969, col. 1, lines 1-30).

A disadvantage of the known device is its low productivity and narrow scope, because heat treatment with obtaining the specified parameters and properties of ring products of a more complex configuration is almost impossible.

The proposed invention solves the following problems: increasing productivity, reducing the cost of heat-treated products while reducing energy costs for their production.

The technical result obtained by carrying out the invention is as follows: the stable obtaining of geometric dimensions and ensuring a given level of mechanical properties of steel products after heat treatment both with internal and external heating of the proposed device with a large number of ring products in a heating device, providing heat treatment of ring products with a more complex configuration.

The specified technical result is achieved in that in a device for producing high-strength steel thin-walled ring products of exact geometric dimensions in a heating device containing a hollow mandrel made of a material having a larger coefficient of linear expansion than the material heat-treated on the mandrel of the ring products, it is new that the device is equipped with a stable nth number of hollow mandrels made of austenitic steel and a set of fixing spacers for separating mandrels made in the form of a ring with with a spacer disk, the outer diameter of the rings is slightly smaller than the inner diameter of the mandrels, and the disks separating the mandrels among themselves are made on some spacers protruding behind the mandrels, on other spacers partially overlapping the end of the mandrels, in addition, for mounting ring articles with an inner corrugation on the stand from the mandrels each mandrel is made of collapsible of two parts, one of which is a structure with one or more protruding steps, and the other is a structure with internal steps in contact with external per howling, and at the junction of the components of the mandrel made a groove for fixing the ring products of the inner corrugation.

An alternative embodiment of the structural elements of the device provides a heat treatment of the ring products of a simple and complex configuration to obtain the same technical result.

Technical solutions with features that distinguish the claimed solution from the prototype are not known and do not follow explicitly from the prior art, this suggests that the claimed solution is new and has an inventive step.

The drawings show:

figure 1 - device with the n-th number of mandrels and spacers;

figure 2 - device with the n-th number of composite mandrels and spacers;

figure 3 - device with the n-th number of composite interlocking mandrels;

figure 4 - heating chamber with a device for heating simple ring products;

figure 5 - heating chamber with a device for heating ring products with an internal corrugation.

A device for producing high-strength steel thin-walled ring products of precise geometric dimensions in a heating device comprises a rack 1 (a, b, c) of the nth number of hollow mandrels 2a (see Fig. 1), 2b (see Fig. 2), 2c (see Fig. 3) made of austenitic steel and a set of fixing spacers 3a (see Fig. 1), 3b (see Fig. 2) for separating the mandrels. Spacers are made of steel in the form of a ring with a girdle disk, the outer diameter of the rings is slightly smaller than the inner diameter of the mandrels.

Structural elements "mandrel" and "locking spacer" are created as an alternative, expanding the scope of the device. Elements are made as follows:

a) for heat treatment of simple thin-walled ring products (see Fig. 1), the hollow mandrels 2a are separated by fixing simplets 3a with girdle disks, the disks are protruding beyond the mandrels;

b) for heat treatment of thin-walled ring products with an internal corrugation (see Fig. 2), each hollow mandrel 2b is made of two parts 4, 5, one of which is a structure with a protruding step, and the other with an internal step in contact with the external the first 4, at the junction of the components of the mandrel, a groove 6 is made for fixing the heat-treatable ring products with an internal corrugation. The mandrels are separated by fixing spacers 3b, the girdle disks of which are partially overlapping the end faces of the mandrels;

c) for heat treatment of thin-walled ring products with an internal corrugation (see Fig. 3), each hollow mandrel 2c is made of two parts 4, 5, one of which is a structure with two protruding steps, and the other with two internal steps in contact with the external first 4, moreover, through one pair of contacting steps, the assembly of the components of one mandrel, and through another pair of contacting steps, the installation of each subsequent mandrel in the previous one. At the junction of the components of the mandrel, a groove 6 is made for fixing the heat-treatable ring products with an internal corrugation.

The device operates as follows.

Heat treatment of products from maraging steel using the device is carried out or

1) in the heating chamber of the industrial vacuum bell-type electric furnace SGV-2, 4-2 / 15 IZ, where an external heating scheme of mandrels made of austenitic steel with ring products located in the form of a rack along the central axis of the cylindrical chamber is used; or

2) in a heating chamber with a thermal electric heater (TEN), located inside the rack of hollow austenitic steel mandrels coaxially with the chamber cap, in this case, the internal heating pattern of mandrels with ring products located on them is used.

Before starting the heat treatment, a rack is formed at any choice of the characteristics indicated by the alternative:

1) the rack 1a is composed of the n-th number of mandrels 2a, spacers 3a and ring products of simple form 7;

2) the rack 1b is composed of the nth number of composite mandrels 2b, spacers 3b and ring products with an inner corrugation 8;

3) the rack 1B is composed of the n-th number of composite mandrels 2B and ring products with an inner corrugation 8.

The number n in the rack of mandrels is determined by the height of the working space of the heating chamber 9. Ring products are mounted on mandrels with an optimal clearance. To install any of the selected racks from mandrels with ring products in the heating chamber 9, an additional device 10 is used. To illustrate the use of the device, the drawings show a heating chamber 9 with an internal heating circuit using a heat electric heater 11:

- figure 4 - for heating racks of mandrels with ring products of simple form 7;

- figure 5 - for heating racks of mandrels with ring products with an inner corrugation 8.

The heat treatment process is carried out in a non-oxidizing environment. As the heating due to the linear expansion of the steel, each mandrel 2 (a, b, c) comes in contact with the cold ring products and compresses them evenly, smoothing out shape defects. Ring products are equally plastic throughout the diameter. With further heating, the expansion of all links of the rack from mandrels with ring products occurs simultaneously, forming the geometric dimensions and mechanical properties of the products.

The use of the inventive device in the heat treatment of ring products made of maraging steel makes it possible to obtain stable geometric dimensions of the products while ensuring a given level of mechanical properties in accordance with the requirements of design documentation.

Claims (1)

A device for producing high-strength steel thin-walled ring products of precise geometric dimensions in a heating device containing a hollow mandrel made of a material having a higher coefficient of linear expansion than the material heat-treated on the mandrel of the ring products, characterized in that the device is equipped with a rack of the nth number of hollow mandrels made of austenitic steel and a set of fixing spacers for separating mandrels made in the form of a ring with a girdle disk, the outer diameter of the rings is slightly smaller e of the inner diameter of the mandrels, and the disks separating the mandrels among themselves are made on some spacers protruding beyond the mandrels, on other spacers partially overlapping the end face of the mandrels, in addition, for mounting on a rack of mandrels of ring products with an internal corrugation, each mandrel is made of two parts, one of which is a structure with one or more protruding steps, and the other is a structure with internal steps in contact with the external first, and at the junction of the components of the mandrel you the groove for fixing the ring products with the inner corrugation is full.

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