SU825657A1 - Method of treatment of parts - Google Patents

Description

The invention relates to chemothermal processing of steel products and can be used for surface hardening of heavily loaded parts of agricultural machines and tractors.

A known method of processing parts from iron-carbon alloys, including plastic deformation at intervals at room temperature and high-speed heating (1000-4000 ° C / s) for the final heat treatment (quenching) W ·

This method reduces warping and improves productivity, but does not fully utilize the possibilities of hardening the surface.

A known method for processing steel parts is that the parts are preliminarily subjected _to cold or hot plastic deformation with degrees, respectively. 15-35 and 15-502 and stabilizing tempering at 250-600 ° C (£ |.

However, the existing processing method is aimed solely at intensifying the process of chemical-thermal treatment and does not eliminate warpage of parts.

The purpose of the invention is the reduction of warpage of products.

To achieve this goal according to the processing method, including cold plastic deformation, heating, chemical-thermal treatment and cooling, additional deformation of the areas previously hardened by plastic deformation is performed.

In addition, the treatment includes cold plastic deformation, heating at a rate of 1000-4000 ° C / s, cementation, quenching to a temperature of quenching and quenching with the application of additional elastic deformation in the process of quenching and quenching.

‘Processing also includes cold plastic deformation, heating with

825657 4 at a rate of 1000-4000 ° C / s, low-temperature nitriding and cooling with the imposition of additional elastic deformation in the process of nitriding and subsequent cooling.

The plastic deformation of the surface layer portions produce closed intervals which are isolated from each other and arranged in the center of the deformed portions w that allows the most efficient distribution of the density of defects and dislocations due to multiple their sliding and simultaneously drastically reduce the influence on the characteristic intervals ι ₅ the characteristics of the formed diffusion layer. The effect of partial resorientation of the grains of the substructure during a long saturation process is eliminated by elastic deformation, which 20 is carried out with rapid cooling of the parts after chemical-thermal treatment. The parts are elastically fixed, the coincidence of the elastic deformation in phase with the preliminary plastic deformation, i.e. the extension of the action of elastic deformation to the hardened areas obtained during plastic deformation makes it possible to use the intervals for elastic relaxation arising in the processes of rapid cooling of internal stresses during elastic deformation. Intensification and non-deformation of the process is also facilitated by high-speed induction heating for chemical-thermal treatment, which partially preserves orientation in the substructure and defect density, and also reduces the total processing time. 10

The drawing shows a device for performing these operations and the sequence of operations of the method.

Part 1, making translational and rotational motion, plastically 45 deforms with a degree of deformation of 8-15% in the break-in rollers 2 located at an angle of 90 ^{0 to} each other and offset along the axis by the value of the specified technological interval. Ob- ₅₀ inaccurate rollers 2 form continuous intersecting deformed on the surface of the part to a depth equal to 0.5-1.0 of the depth of the diffusion hardened layer, sections 3 (from 55 of one roller 'and 4 (from the second roller) with closed intervals 5 located in the center of the deformed sections.

The plastically deformed part, while maintaining rotational and translational motion, is moved to an induction heater 6, in which, using an inductor 7 with a magnetic circuit 8 (to increase the thermal power of the inductor), it is heated to a temperature of chemical-thermal treatment (950-1050 ° C) at a high speed of 1000 -4000¾ / s Simultaneously with high-speed heating, a gas carburizer is supplied to the heating zone using an injection device 9. The induction heater 6 and the injection device 9 have a certain length associated with the translational speed of the parts in such a way as to ensure the formation of a diffusion surface layer during the passage of the part through the heater 6 depths.

Parts 1 with a formed diffusion surface layer at the outlet of the heater 6 fall into the rolling rollers 10, where, while maintaining rotational and translational motion, they undergo elastic deformation and rapid cooling due to the fact that the rollers are water-cooled and, thus, provide the cooling rate of the part after chemical heat treatment. Elastic deformation after chemical-thermal treatment in the rollers 10 with the help of a correlating device is performed in areas deformed by preliminary plastic deformation by the rollers 2, while maintaining the interval of the deformed sections. The rollers 10. are located at an angle of 90 ° and are offset along the axis by the value of the technological interval of preliminary plastic deformation.

Cooled to the quenching temperature, the part, while maintaining rotational and translational motion, enters into the rolling quenching rollers 11, equipped with axial air-water nozzles, where it undergoes elastic deformation and high-speed quenching cooling due to the water cooling of the rollers 11 and 12, thereby ensuring the cooling speed of the part 300 700 ° C / s, up to 200 ° C.

Elastic deformation during the hardening process in the rollers 11 is carried out in areas deformed by preliminary plastic deformation by the rollers 2, while maintaining the intensity of the deformed sections.

On the details of rectangular, square and other sections, the implementation of the proposed technical solution with a small reconstruction of the break-in rollers and the use of rotating magnetic fields for the induction heating is possible. The ratio of the areas of the deformed areas and the closed intervals between them should be kept in the range from 20: 1 to 100: 1.

Example 1. Spend chemothermal processing of vacuum rollers of two sizes of steel 20HGT. Parts are rolled around with rollers in increments of 20 mm at a speed of 50 rpm and a force of 0.8-1.2 tons, the rollers are located at an angle to each other equal to 90 ° and are offset along the axis by an interval equal to 3.212.0-0 5 mm. The depth of the deformed layer of 0.350.95 mm, the degree of plastic deformation of 5-15%. Then the rollers are heated for cementation at a speed

1000 .. .4000 ° С / s to 950-1050 ° С. Gas carburetor overpressure

120 .. .180 mm water column The cementation time is 90-240 s, the depth of the cement layer with 1/2 of the transition zone is 0.68-0.96 mm. After the parts of the induction heater, in which they were subjected to chemical-heat treatment, pass, the rollers undergo rapid cooling from 950-1050 ° C to 820-840 ° C at a speed of 80-120 ° C / s by rolling in water-cooled rollers, made and arranged similarly to the rollers for plastic deformation. The force on the rollers, depending on the diameter of the workpiece and the grade of steel, ranges from 30,120 kg, the cooling time is 1.5-3 s. Then the rollers are subjected to rapid cooling from 820-840 ° C to 20-180 ° C at a speed of ZOO-7OO * C / s with water-cooled rollers with axial air-water nozzles, designs and located similarly to rollers for plastic deformation. Force on rollers 30-120 kg, water pressure c. Air-to-water nozzle

3-4 ati, air pressure 1.0-1.5 ati

IS

Example 2. Nitriding of rollers from steel .38 HMOA with a diameter of 1410.05 mm and a length of 27310.5 mm is carried out. Preliminary plastic deformation 825657 · 6 tion and heating to a nitriding temperature of 525125 ° C is carried out analogously to example 1. Ammonia consumption in sections of an induction heater 10012 l / min, nitriding time 210.2 min.

The deforming force on the rollers during the cooling process is 80-100 kg, the cooling rate of the parts is 150200 ° C / min. The depth of the nitrided layer is 0.2-0.3 mm, the hardness of the layer is HRC 63-64, and warpage is 0.15.

All operations of the method are performed in a continuous-sequential manner on a installation with a horizontal arrangement of supporting and rolling-in devices with a heating source (standard installation B, 4G-1-100 / 0066). Productivity of the installation is 5595 mm / s.

Using the proposed method for processing parts provides the following advantages in comparison with the known ones: the ability to combine the intensification of the processes of chemical-thermal treatment with their deformation-free ability to carry out high-performance 'processes of chemical-thermal processing in a continuous-sequential way and improving the quality of chemical-thermal and final heat treatment.

Claims (3)

The invention relates to chemical heat treatment of steel products and can be used for surface hardening of heavy loaded parts of agricultural machines and tractors. From: The Westen method of processing parts from iron-carbon alloys, including plastic deformation with parts at intervals at room temperature and high-speed heating (1000–4000 C / s) for the final physical treatment (hardening) l. This method reduces warping and increases productivity, however, it does not fully use the possibilities of surface hardening. A known method of treating steel parts is that the parts are previously subjected to cold or hot plastic deformation with degrees of corresponding go. 15-35 and 15-50% and stabilizing tempering at 250-600 0 I. However, the process of processing is aimed solely at intensifying the process of chemical heat treatment and does not eliminate the distortion of parts. The purpose of the invention is to reduce the distortion of products. In order to achieve this goal, according to the treatment method, which includes cold plastic deformation, heating, chemical-thermal treatment and cooling, creeping deformation of the areas previously strengthened by plastic deformation is performed. In addition, the treatment includes cold plastic deforming, heating at a speed of 1000–4000 ° C / s, cementation, pushing up to the quenching temperature, and quenching with the imposition of additional elastic deformation during the pressing and quenching process. The treatment also includes cold plastic deformation, heating at a rate of 1000-AOOO C / s, low-temperature nitriding and cooling with the imposition of additional elastic deformation during the nitriding process and subsequent cooling. Plastic deformation of the surface layer is carried out in closed sections, the intervals in which are isolated from each other and located in the center of the deformed areas, which makes it possible to most efficiently distribute the density of defects and dislocations due to their repeated slip, and at the same time, drastically reduce the effect of the intervals on characteristics of the formed diffusion layer. The effect of partial resorientation of the grains of the substructure during the long process of saturation is eliminated by elastic deformation, which is carried out during rapid cooling of parts after chemical-thermal treatment. The parts are resiliently fixed, with a drop in other deformation in phase with preliminary plastic deformation, i.e. The spreading of the effect of elastic deformation on the hardened areas, obtained during plastic deformation, makes it possible to use intervals for elastic deformation for relaxation of internal stresses arising in the processes of rapid cooling. 1 ntenification and processlessness of the process also contribute to high-speed induction heating for chemical-thermal treatment, which partially preserves, orientation in the substructure and the density of defects, and also reduces the overall processing time. The drawing shows a device for carrying out these operations and a sequence of operations of the method. Part 1, having made a translational and destructive motion, is plastically deformed with a degree of deformation of 8–15% in rolling rollers 2, i acno laid at an angle of 90 to each other and displaced along the axis by the value of a given technological interval. Rolling rollers 2 form on the surface details of continuous re-reacted deformed to a depth equal to 0.5-1.0 depths of the diffusion hardened layer, sections: 3 from one roller) and 4 (from the second roller) with closed intervals 5 located in the center of the deformed plots. 74 The plastically deformed part, preserving the rotational and translational motion, moves to the induction heater 6, in which by means of an inductor 7 with a magnetic core 8 (for increasing the thermal power of the inductor) is heated to a temperature of chemical heat treatment (950-1050 C) at a high speed of 1000 -4000 C / s. Simultaneously with the high-speed heating, the gas carburizer is supplied to the heating zone by means of a pilot device 9. The injection heater 6 and the injection device 9 have a certain length associated with the speed of the translational movement of parts in such a way as to ensure the formation of a diffusion surface layer of a certain depth during the passage of the part through the heater 6. The parts 1 with the formed diffusion surface layer at the exit of the heater 6 fall into the rolling rollers 10, where, maintaining rotational and translational movement, they are subjected to elastic deformation and rapid cooling due to the fact that the rollers are water-cooled and, thereby, provide the rate of cooling the part after chemical - thermal processing. Elastic deformation after chemical-thermal treatment in rollers 10 with the help of correlating device is carried out in areas deformed by preliminary plastic deformation by rollers 2, while maintaining the interval network of deformed sections. The rollers 10. are located at an angle of 90 and are offset along the axis by the value of the technological interval of the preliminary plastic deformation. The part cooled to the quenching temperature, maintaining rotational and translational motion, enters the rolling quenching rollers 11, equipped with axial air-water nozzles, where it is subjected to elastic deformation and high-speed quenching cooling due to the water cooling of the rollers 11 and 12, thereby ensuring the cooling rate of the part 300700 ° C / s, up to 200 ° C. Elastic deformation in the aakalki process in rollers I1 is produced in areas deformed by preliminary plastic deformation with 5 rollers 2, maintaining an intense spine deformed parts. On parts of rectangular, square and other sections it is possible to implement the proposed technical solution with a small reconstruction of the rollers and use of magnetic fields for induction heating of rotating rollers. The ratio of the areas of deformed areas and closed intervals between them should be kept in the range from 20: 1 to 100 :. Example 1. Chemical-thermal treatment of vacuum rollers of two sizes of steel 20XHT is carried out. Details roll with rollers with a pitch of 20 mm at a speed of 50 rpm and a force of 0.8-1.2 tons, the rollers are angled to each other, equal to 90 °, and axially displaced by an interval value equal to 3.2t2.0 -0.5 mm. The depth of the deformed layer is 0.350, 95 mm, the degree of plastic deformation is 5-15%. Then the rollers are subjected to heating under cementation with a speed of 1000 ... to 950-1050 ° C. Gas carburetor overpressure 120 ... 180 mm water column The cementing time is 90-240 seconds, the cement layer depth with 1/2 of the transition zone is 0.68-0.96 mm. After passing the details of the induction heater, in which they were subjected to chemical-thermal treatment, the rollers are rapidly cooled from 950-1050®С to 820-840®С at a speed of 80-120 ° С / s by running in water-cooled rollers similar to plastic deformation rollers. The force on the rollers, depending on the diameter of the workpiece and the steel grade, ranges from 30120 kg, cooling time 1.5-3 s. The rollers are then subjected to rapid cooling from 820-840 ° C to 20-180 ° C at a speed of 300-700 c7C with water-cooled rollers with axial air-water nozzles, made and arranged similarly to the plastic deformation rollers. The force on the rollers 30-: 120 kg, the water pressure in the air-water nozzle is 3-4 bar, the air pressure is 1.0-1.5 bar. Example 2. Nitrogenation of rollers made of .38 XMOA with a diameter of 14tO, 05 mm and a length of 27310.5 mm. The preliminary plastic deformation of 7 qi and heating up to the nitriding temperature is carried out as in Example 1. Ammonia consumption. In the induction heater sections 10012 L / min, nitriding time, 2 min. The deforming force on the rollers during the cooling process is 80-100 kg, the cooling rate of the parts is 150200 C / min. The depth of the nitrated layer is 0.2-0.3 mm, the hardness of the layer is HRC 63-64, the distortion is 0.15. All operations of the method are carried out in a continuous-sequential way on a unit with a horizontal arrangement of supporting and rolling devices with a heating source (standard installation B 4G-1-100 / 006b). Plant capacity 5595 mm / s. The use of the proposed method of processing parts provides the following advantages in comparison with the known ones: the ability to combine the intensification of chemical heat treatment processes with their deformation-free ability to perform high-performance chemical heat treatment processes in a continuous-sequential manner and increase the chemical-thermal and final heat treatment performance. Claims 1. A method of machining parts, including cold plastic deformation,; heating, chemical heat treatment and cooling, distinguishing and so that, in order to reduce the distortion of products, additional deformation of the sections previously strengthened by plastic deformation is performed. 2. Method POP.1, characterized in that it conducts cold elastic deformation, heating with a corrosion rate of 1000-4000 s / s, cementation, airing to quenching temperature, hardening with the imposition of additional spring deformation in the process of podstuivanie and hardening. 3. Method POP.1, distinguished by the fact that cold elastic deformation, heating with a corrosion rate of 1000-4000 C / s, low-temperature nitriding and cooling by superposition of additional elastic are carried out 18256578 deformation during nitriding .1. USSR author's certificate and subsequent cooling. No. 670621, cl. C 21 O 1/78, 1976. Sources of information, 2. USSR author's certificate taken into account in examination No. 331101, cl. From 21 D 1/78, 1970.