SU1157093A1 - Method of heat-treatment of high-speed steel components - Google Patents

Abstract

METHOD OF QUITING PARTS FROM QUICKLY CUTTING STEEL, including heating to quenching temperature, holding and cooling, characterized in that, in order to reduce energy costs while eliminating deformation, the parts are heated in a graphite device in a fixed position to a temperature of 150-200C below the quenching temperature. (rt

Description

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about

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The invention relates to mechanical engineering and can be used in the heat treatment of high-speed and alloyed steels.

There is a method of quenching high-speed steel with heating in molten salts, in particular in barium baths at 1240-1АУО СD.

The disadvantages of the method are the hazard of production, explosion hazard, corrosive surface, the presence of deformation, the need for special equipment.

There is a known method of quenching parts from tool steels, including heating for quenching in a salt bath at 1230–110 ° C with fixation of parts with the help of fine powder in a graphite cup. The method eliminates the description, decarburization and warping of small-sized parts C2J.

However, the method requires high-temperature salt baths, the disadvantage of which is also the harmfulness of production, danger of explosion, and corrosion of the surface.

The closest to the present invention is a method of quenching high-speed steel parts, consisting in preheating up to 780,800 ° C and final heating in electric furnaces with a protective front to 1050-1300 ° C, followed by air cooling. This method eliminates the operation of washing off the salts, reduces the percentage of parts rejected by separating the surfaces, eliminates the use of molten salts, and reduces the harmfulness of the production of Cs 1.

However, expensive high-temperature furnaces are necessary for carrying out the known method, since it is not possible to use low-temperature equipment with a maximum temperature of 1050-1100 ° C for high-speed steels, since low-quenched martensite with low resistance properties is obtained from these temperatures. In addition, the method does not provide high-quality machining: parts with a diameter of up to 3 mm in deformation.

The aim of the invention is to reduce energy costs while avoiding deformation.

This goal is achieved by the fact that according to the method of quenching high-speed steel parts, which includes heating to quenching temperature, hardening and cooling, the parts are heated in a graphite device in a fixed position to a temperature of 150–200 ° C below the accepted quenching temperature.

The use of graphite as a material for adaptation allows the use of low-temperature equipment. This is due to the fact that the temperature of parts heated in a graphite fixture is 150–200 ° C in the furnace. The temperature increase is achieved by the exothermic carbon (graphite) combustion in oxygen, which is always present in the protective atmosphere of the furnace (1050-1100 o. If the furnace temperature is lower, the parts heated in the graphite device will have a temperature below 1200 ° C, which will lead to underheating (incomplete austenization) and subsequently to the low cutting properties of parts. At a furnace temperature higher, the temperature of parts in a graphite device will reach more than 1300 ° C, which will lead to melting of the surface of the parts. fit during heating and cooling does not undergo structural transformations and does not introduce additional deformation in the part subjected to quenching, and the fixing parts in a graphite fixture during the heating and cooling eliminates deformation.

The method is as follows.

in a way. I

Parts of high-speed steel are clamped in a graphite device and heated in a furnace having 1050-1, held at this temperature for 15-20 minutes. During this period of time inside the graphite device, the temperature rises 150-200 ° C above the furnace temperature, and the part heats up to 1200-1250 ° C. The temperature in graphite is determined experimentally by control thermometers in graphite and in the furnace. After aging at the temperature of austenization, the parts in the graphite device are cooled to room temperature.

Example 1. Heat treatment of needles with a diameter of 1 mm and a length of 70 mm, made of steel P 18, is carried out. Parts are supplied to a graphite device of material PGM-V, which consists of RSYX. plates with sockets in the form of prisms for details. These plates are clamped by means of a bolted joint. Then a graphite fixture with parts is placed in a conveyor furnace of the Refractory type with a protective medium having a temperature of 1100 ° C, which is held for 15 minutes. After that, the parts are cooled down to about 1 ° temperature and subjected to subsequent operations.

Example 2. Thermal treatment of cannon drills from R6M5 steel with a diameter of 2 mm and a length of 60 mm was carried out. The drills are clamped in a graphite device of the material MPG-6. Graphite devices together with the drills are placed in a furnace of the Refractory type with a protective medium having a temperature, held for 20 minutes and cooled to room temperature. After completion, parts are subjected to subsequent operations.

Example 3. Parts made of steel R18 diameter

1 mm, 70 mm long, previously: heated to 780-800C, is heated in a furnace with a protective atmosphere to, hold and cooled in an upright position. It is then subjected to subsequent operations.

To obtain comparative data, heat treatment of parts made of P18 with a diameter of 1 mm, a length of 70 mm without a graphite fixture was carried out according to the mode: heating up to, hold for 20 minutes, cooled in air.

The table presents the results of heat treatment.

The proposed method makes it possible to perform quenching in electric furnaces having a maximum temperature, reducing the deformation of long parts with a diameter of up to 3 mm after quenching; simplification of the technological process by eliminating the leveling operation; the possibility of obtaining parts in finished form after heat treatment (without an allowance for the subsequent grinding operation). The use of the method only for tools with a diameter of 1.0 to 2.0 mm made it possible to obtain savings of 22.7 thousand rubles.

1x70 P18 Pre 1100 1270 lag

e 2x60 R6M5 -,

9Yаh70 R18 Iz1270 Vestn

560 62-64 1

1060 1220

540 62-64 1

62-64

70 Requires leveling and grinding operations

01x70 P18

1100

Offered without graphite

Table continuation

560 50-52

50

Claims (4)

METHOD FOR HARDENING PARTS FROM QUICK CUT STEEL, including heating to a quenching temperature, holding and cooling, characterized in that, in order to reduce energy consumption while eliminating deformation, the parts are heated in a graphite fixture in a fixed position to a temperature of 150-200 ° C below the accepted temperature! hardening. 1157093. ² The aim of the invention is to reduce energy consumption while eliminating deformation. The goal is achieved 5 by the fact that according to the method of hardening of parts from high speed steel, which includes heating to a temperature. Quenching, holding and cooling, the parts are heated in graphite 10 fixture in a fixed position to a temperature of 150-200 ° C ¹ below the accepted quenching temperature. The use of graphite as a material for adaptation allows the use of low-temperature equipment. This is explained by the fact that the temperature of parts heated in a graphite device is 150-200 ° C higher than the temperature available in the furnace. The temperature increase is achieved by the exothermic reaction of carbon (graphite) combustion in oxygen, which is always present in the protective atmosphere of a 125 Ρθ furnace (1050-1100 ° C). If the temperature in the furnace is below 1050 ° C, then the parts heated in a graphite device will have a temperature below 1200 ° C, which will result 3Q 'to underheating (incomplete austenization) and subsequently to low cutting properties of parts. When the temperature in the furnace is above 1100 ° С, the temperature of the parts in the graphite device will reach more than 1300 ° С, which will lead to the melting of the surface of the parts. In addition, graphite during heating and cooling does not undergo structural transformations and does not introduce additional deformation into the parts subjected to hardening, and the fixation of parts in a graphite device during heating and cooling excludes deformation. $ 4 The method is as follows. I Parts made of high-speed steel are clamped in a graphite device and heated in a furnace having 50 1050-1100 ° С, they are held at this temperature for 15-20 minutes. During this period of time within the graphite device temperature rises to 150-200 ° C tempe55 perature above the furnace, and the part is heated to _t 1200-1250 ° C. The temperature in graphite is determined experimentally by control thermometers in graph1