SU1523287A1 - Method of producing articles - Google Patents

Abstract

The invention relates to the field of metallurgy, in particular to the chemical and heat treatment of steels for the manufacture of cores, cores, poles of electromagnetic devices. The aim of the invention is to increase wear resistance while maintaining magnetic properties and reducing the complexity of the process. The method is carried out by vacuum annealing at 1000 - 1170 ° C for 30 - 45 minutes with simultaneous local cementation with filling the cavity bounded by a sealing seat, a mixture containing activated carbon, trilon-B and lanthanum hexaboride at a ratio of 1: 1: 1. Then the product is cooled at a speed of 300–400 ° C / h to 900 ° C, and to room temperature - at the generally accepted speed, after which laser hardening, grinding and finishing of the saddle part and final tempering at 300–350 ° C are performed. 1.5 h. 1 s. f-ly, 1 tab.

Description

The invention relates to the field of metallurgy, in particular to the heat treatment of steels for the manufacture of cores, cores, poles of electromagnetic devices, and more specifically it relates to the vacuum chemical-heat treatment of small precision parts of electrovalves made of magnetically soft steels and alloys.

The purpose of the invention is to increase the magnetic properties and reduce the complexity of the process.

The goal is achieved by the fact that, according to the method of vacuum annealing at 1000–1170 ° C, local local cementation is carried out for 30–45 minutes with backfilling of the cavity bounded by a sealing seat, a mixture containing activated carbon, Trilon-B, and lanthanum hexaboride in equal quantities , then laser hardening of the cemented surface is performed, followed by tempering at 300-350 ° C.

At the same time, in order to reduce the brittleness of the thin saddle part, cooling after the end of exposure under vacuum annealing with simultaneous cementation is carried out at a speed of 300-400 ° C / h to 900 ± 10 ° C, then at a generally accepted speed. At the same time, in order to increase the processability, simplify the preparation of chemical-heat treatment, improve the quality, laser quenching is carried out directly after annealing with cementation on the sealing surfaces without their machining, and stabilizing tempering at 300-350 ° C is carried out after lapping and finishing the . The influence of each of the factors on the course of processes in the surface zone and in the base metal of Korea is as follows:

Qi cement with high-temperature annealing, carried out for high-chromium magnet steels of type 10X13, 16X-VI in the range of 1000-1170 ° C, allows to obtain a diffusion layer in a short time

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increased wear resistance. The active cementation time is limited to 30-45 minutes, with a total duration of vacuum annealing of 240 minutes to eliminate through-diffusion and possible embrittlement of sealing seats;

the zone backfill containing activated carbon, trilon-B and lanthanum hexaboride limits the degree and depth of diffusion saturation, its activity decreases after 30-50 min. the depleted composition introduced into the compaction zone does not cause an increase in the carbon and boron concentration in the layer while annealing is continued for obtaining magnetic properties;

accelerated cooling from annealing temperatures to temperatures above the Curie point does not lead to a decrease in magnetic properties, but eliminates the formation of a carbide mesh in the cemented zone, allows us to obtain a more stable and uniform structure for subsequent laser hardening;

laser hardening on the surface with increased roughness and better optical characteristics, immediately after vacuum annealing with simultaneous cementation, provides stable hardness, facilitates control of the laser hardening process, improves the quality of laser hardening;

stabilizing tempering in the range of 300-350 ° C after finishing and lapping does not cause a decrease in magnetic properties, does not increase the fragility of the layer, does not cause additional thermal deformation of thin Koreas.

As a result of processing by the proposed technology, it is possible to increase the wear resistance and hardness of the sealing surfaces, to exclude brittle chipping under multi-cycle loading, to ensure a high level of magnetic properties of the base material with minimal heat-intensiveness. The reliability of the valve assemblies increases, and the service life increases by a factor of 1.3 times.

Example: Ya.kor magnetic valves were made and processed from 16X-VI steel, vacuum annealing was carried out in furnaces with a backfilling of the zone of the saddle part of korea with a mixture of activated carbon, crushed to a dust-like fraction, trilon-B and lanthanum hexaboride powder in the ratio 1: 1: 1, placing the parts in a stainless steel getter container.

After warming up to 1150 ° C in a vacuum of 1.33-10 Pa and holding for 45 minutes, argon was supplied and after 10 minutes annealing was continued according to the standard mode to a total exposure time of 240 minutes, and then the cage was cooled to 900 ° C at a rate of 350 ° C / h, then in the standard mode 100 ° C / h to

750 ° C / h and 250 ° C / h to 200 ° C. Laser hardening was carried out at the Kvant-15 setup with a spot diameter of 0.8-1.0 mm and a pulse duration of 2.5-4.0 ms with a working

voltage 800 with blown helium. Vacation after grinding the sealing surface was carried out in a vacuum cabinet of NSEL at 350 ° C for 1.5 hours. Pressing the volume bounded by hardened shoulders was carried out

40-P.

As shown by research and testing of the Koreas and valves during the processing by the proposed method, the strength and hardness of the saddles increase by 2-2.5 times in comparison

processed by a known method and in all cases higher than when processed by the prototype. The microhardness of the sealing beads is But 49 601-625 versus But 49 220-231 for the 1bH-VI steel annealed in the standard mode. As a result, the fixing of the sealing fluoroplastic is improved, the service life increases by an order of magnitude and the reliability of the valve is increased. The magnetic properties of the main core material are not inferior to those specified in accordance with GOST.

In the table and examples of the method are given the comparative properties of high-chromium magnet of soft steel when machining in various modes.

Thus, the proposed method is effective, easy to implement, does not require

additional costs for equipment and auxiliary materials and will solve the problem of increasing the performance of micro-valves with multi-cycle loading.

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Claims (2)

1. A method of manufacturing products, mainly korea of solenoid valves from high-chromium steel, including vacuum annealing, chemical-thermal treatment in a carbon-containing medium, followed by laser hardening of the diffusion layer and stabilizing annealing, which is different in order to increase wear resistance while maintaining magnetic properties and reduce the complexity of the process, chemical-heat treatment is carried out locally by filling into the cavity bounded by a sealing saddle of a carbon-containing medium containing in equal quantity activated carbon, trilon-B and lanthanum hexaboride, the chemical heat treatment is combined with vacuum annealing and carried out for 30-45 minutes, and tempering is carried out at 300-350 ° C. 2. A method according to claim 1, characterized in that in order to reduce brittleness, cooling to. 900 ° C in the process of vacuum annealing is carried out at a rate of 300-400 ° C / h.  - in the column, the reset time with grouting for all positions, the total annealing time is 240 min in all cases.