RU44674U1 - DEVICE FOR NON-OXIDIZING HEAT TREATMENT OF STEEL PRODUCTS - Google Patents

Abstract

The utility model relates to the field of engineering, in particular to the technique of heat treatment of parts and tools in a protective environment. A device for non-oxidative heat treatment of steel products consists of a continuous, without holes, bottom and shell, trellised bottom, mounted on an annular frame, a handle and a cover. The bottom and the shell are interconnected by fusible inserts. The lattice bottom is mounted on the inner annular protrusion in the lower part of the shell. The shape and size of the mesh bottom cells depend on the aggregate fraction and the size of the workpieces. The products are placed in the device in a filler layer, which can be used as a carburetor, spent carburetor or cast iron filings. When hardening, as well as tempering of steel products, prone to temper brittleness, fusible inserts are installed in the device. When the device with products in the furnace is heated, the fusible inserts melt, freeing the device from the bottom. After warming up, the device without bottom is removed from the furnace, shaken to remove aggregate and transferred with the products remaining on the mesh bottom to the coolant. During annealing, normalization, tempering and cementation, steel inserts are installed in the device. The mesh bottom is optional. After heating, the device with products in the aggregate layer, depending on the type of heat treatment, is cooled with an oven or in air. Thus, the proposed device allows for various types of heat treatment in a filler medium that prevents oxidation and decarburization of the surface of the product, including hardening. When hardening, due to the detachment of the bottom, the device allows you to quickly remove the aggregate and cool the product in a hardening environment.

Description

A device for non-oxidative heat treatment of steel products relates to the field of engineering, in particular to the technique of heat treatment of parts and tools in a protective environment.

A device is known for heat treatment of steel products in a protective environment, for example, in a layer of a carburetor, a used carburetor, or cast-iron sawdust, which is a box with a lid, the so-called cementation box (see A.A. Shmykov, Thermist Handbook, Fourth Edition, Mashgiz, M ., 1961, pp. 103-104).

The disadvantage of this device is that it can only be used for cementation, non-oxidative annealing, as well as for non-oxidative tempering of hardened products. It is impossible to harden in such a device, since it is necessary to remove the box from the furnace, remove the lid, remove the filler layer, remove the products and transfer them to the quenching liquid. All these operations would have to be performed at a high temperature: 800-1000 ° C., Depending on the steel grade, which is often very difficult to perform. In addition, it is impossible to quench martensite steel products with low stability of supercooled austenite in the decomposition interval of type I and II, so time will be lost on the above operations.

The closest in technical essence and the achieved result - the prototype is a device for non-oxidative heat treatment of steel products (see I.M.Sergeychev, A.M. Pechkovsky. Heat treatment of cutting and measuring tools, Mashgiz, M., 1960, p. 24).

The device is a basket, the bottom and the shell of which are interconnected inseparably. The bottom and the shell may be continuous, or have holes. The basket has

handle and can be equipped with a cover. Products in the basket are laid directly on the bottom or in the filler layer - a carburizer or cast iron sawdust.

The disadvantage of this device is the same as that of the analogue - the inability to perform the hardening operation during non-oxidative heat treatment in the aggregate layer.

The objective of the utility model is to develop a device for non-oxidative heat treatment, which allows not only cementing, annealing and tempering operations, but also hardening operations - cooling products in quenching liquid after heating.

The problem is solved due to the fact that in the device for non-oxidative heat treatment of steel products in the aggregate layer containing the bottom, shell, handle and cover, according to the formula of the utility model, the bottom is attached to the shell by means of fusible inserts, the material of which is selected depending on the temperature regime of a particular heat treatment operation and on the inner annular protrusion in the lower part of the shell there is a lattice bottom fixed on an annular frame, the shape and size of the lattice bottom cells depend on the fraction filler and size of processed products.

The specified set of features is significant, new and solves the problem, since when the proposed device is heated with products, the inserts melt and cease to be a connecting link between the bottom and the shell. The device is removed from the furnace without a bottom, shaken to spill out the aggregate and transferred, together with the products remaining on the grate bottom, to the quenching liquid.

Since the time required to prepare the device with the products for cooling in the quenching medium is insignificant, it is possible to carry out the operation of hardening of products from any steel grade, including steels with low stability of supercooled austenite in the decomposition interval of type I and II stages.

To explain the described device, Fig. 1 shows a section through it with the stacking of products shown in the aggregate layer.

The device consists of: bottom 1, shell 2, trellised bottom 3, fusible inserts 4, handle 5, cover 6.

The proposed device is used for hardening steel products as follows. The shell 2 is installed on the bottom 1 and connected to it through special holes with fusible inserts 4. On the inner annular protrusion of the shell 2, a trellised bottom 3 is installed with the cells that are necessary in shape and size, which are selected depending on the size of the products and the aggregate fraction. A layer of aggregate is poured into the device, products are laid, the top layer of aggregate is poured and tamped. The device is closed by a lid 6 and loaded into the furnace for heating. During the heating process, the fusible inserts 4 melt, so that the device is no longer rigidly connected to the bottom 1, and there is no violation of the continuity of the aggregate layer. After warming up, the device without bottom 1 is removed from the furnace, shaken to pour out aggregate through the grate bottom 3, and then transferred with the products remaining on the grate bottom to the quenching bath.

As a filler, a used carburizer or cast iron sawdust is used. The filler prevents oxidation and decarburization of the surface of the products when heated.

When performing such thermal operations as: annealing, normalization, tempering, cementation, steel inserts are used, since there is no need to separate a solid bottom 1 to remove aggregate. There is also no need to install a trellised bottom 3.

Thus, the proposed device allows for various types of heat treatment in the environment of the filler, which prevents oxidation and decarburization of the surface of the product, including hardening. When hardening, due to the detachment of the bottom, the device allows you to quickly remove the aggregate and cool the product in a hardening environment.

The device allows quenching after non-oxidative heating of steel products, both with high and low stability of supercooled austenite in the decomposition interval of type I and II stages.

Claims (2)

1. Device for non-oxidative heat treatment of steel products in the aggregate layer, containing a bottom, a shell, a handle and a cover, characterized in that the bottom is attached to the shell by means of fusible inserts, the material of which is selected depending on the temperature regime of a particular heat treatment operation, and on the inner ring protrusion in the lower part of the shell is a trellised bottom mounted on an annular frame. 2. The device according to claim 1, characterized in that the shape and size of the cells of the grating bottom depends on the fraction of the aggregate and the size of the processed products.