RU2679114C2 - Method of application of marking on surface layers from metal materials - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used for marking a metal product with a local effect by a high-intensity pulsed magnetic field. Modification is carried out by local magnetic pulse treatment of the surface of the product with the help of magnetic impulses from 1 kA/m to 100 MA/m, with an energy from 0.1 to 50 kJ and a frequency of not more than 50 Hz, created by the inductor. From 1 to 50 pulses are applied, the duration of each of which is more than 5 mcs, with obtaining sections with a modified structure of the surface and subsurface layers at a depth of from 5 mcm to 7 mm. Shape of the inductor's magnetic field hub follows the contour of the surface area of the product with a modified structure. Resulting areas with a modified surface are given labeling.

EFFECT: method provides high wear resistance and durability of marking, as well as increased protection of recorded information.

1 cl, 1 dwg, 1 ex

Description

The invention relates to the application of information, namely, distinctive markings, on metallic materials, in particular, on products made of iron or iron-based alloys, including steel pipes for various purposes, high-quality, shaped and sheet metal.

There are various methods and methods for marking products made of iron and alloys based on it, including steel pipes for various purposes, long, shaped and sheet metal, which differ in both the coding principle and the marking method:

- laser marking (barcode, binary code and other graphic encoding options);

- marking with paint or other paints and varnishes (LKM) (barcode, binary code, two-dimensional color barcode and other graphic encoding options);

- the use of RFID tags (application of a binary signal coding system);

- the use of special surfacing (combined information coding system);

- change in surface roughness (linear or binary coding).

Existing methods have several disadvantages:

- low resistance of laser marking due to shallow penetration, over time, the probability of error increases;

- low marking resistance applied by coatings, which is especially critical when working in aggressive environments;

- the difficult use of RFID tags on the surface of metal products, the high complexity and cost of this method;

- when using surfacing there is a local increase in the thickness of the product and a local increase in the corrosion rate;

- low marking resistance, identified by a change in the surface roughness, since the corrosion processes occurring on the surface over a short period of time offset the difference in roughness;

- a large error when using the pipe passport; during operation, degradation (change) of defects and the appearance of new ones occur.

The prior art various methods for marking metal products using a laser and external heating, the essence of which is the surface change in the structural state of the metal.

A known method of applying markings using laser irradiation (patent RU 2392100 C1 "Method for laser marking the surface of a metal or alloy", 06/20/2010), including laser marking of the metal surface with preliminary construction of the dependence of the depth of marking on the laser power and the subsequent generation of the security code, where Each code number corresponds to a specific marking depth. The size of the recesses does not exceed 100 microns.

The disadvantage of this method is the small marking depth (100 μm) and its physical dimensions, low wear resistance of the marking under various operating conditions of the product, including when exposed to aggressive environments and mechanical external influences.

From patent RU 2462338 C1, 09/27/2012, a method for marking an object is known, including forming an encoded message, consisting of fingerprints, on the surface of the object using local laser heating. Such prints consist of nanostructures in the form of oxides of elements that make up the surface of a metal product. The encoded message contains a barcode or color image of the logo.

The disadvantage of this method is the small thickness of the modified layer obtained by processing the metal surface with a laser, which leads to low resistance to external influences.

Patent RU 2276406, 05/10/2006, describes a method for marking a metal part by applying an electrical impulse between the electrode and the workpiece through a working medium with voltage and power sufficient to ensure breakdown of the working fluid and local structural change in the material in each selected zone, this distinctive marking of the object is the relative position of the zones with a structural change in the metal.

The disadvantage of this method is the difficulty of implementing the method and installation for its implementation, as well as the need to use a working medium - liquid.

Recently, the method of magnetic-pulse processing of various parts of machines and mechanisms has become widespread in industry in order to increase their operational properties. The use of magnetic pulse processing (hereinafter - MIO) allows to lower the surface roughness, increase surface hardness, change the microstructural state and mechanical properties of the surface layers (to a depth of several millimeters) of the processed product.

The use of MIO significantly reduces the internal energy of the processed material; orders the defects of the crystal lattice of a metal with the formation of a subgrain structure; leads to the diffusion redistribution of alloying elements, which increases the surface strength and hardness and, as a result, wear resistance, without changing the shape of the treated surface. The use of MIO also leads to a decrease in surface roughness (see, for example, G. Knopfel “Superstrong Pulsed Magnetic Fields”, published by Mir, Moscow, 1972; IV Bely, SM. Fertik, L.T. Khimenko “Handbook of magneto-pulsed metal processing” ed. At Kharkov State University of the Vishka Shkola Publishing Association, Kharkov, 1977; A.Yu. Kozlyuk, A.G. Ovcharenko, M.O. Kurepin “Justification of the combined scheme magnetic pulse processing of carbide cutting tools ”,“ Polzunovskiy Vestnik ”, 1 / 1-2012 publishing 1st Center FSBEI HPE Altai State Technical University named after II Polzunov (Barnaul 2012).

From the prior art, the closest analogue has not been identified.

The objective of the claimed invention is to obtain hidden (indistinguishable without special devices) markings on the surface of the product, which ensures the possibility of its traceability throughout the life cycle of the product. In addition, the method allows you to record information in an amount sufficient for complete identification of the product.

The technical result of the claimed invention is to increase the reliability of marking, increase the wear resistance and durability of the marking when exposed to external adverse factors, for example, when abrasion, the influence of atmospheric moisture, etc., which leads to an increase in the life of the product with marking, as well as secrecy ( increased protection) of recorded information.

The technical result is achieved through the implementation of the method of applying distinctive marking (code writing) to an item made of metals or alloys based on them, in which the marking is applied by local magnetic-pulse surface treatment of the item using high-intensity magnetic pulses (from 1 kA / m to 100 MA / m) with an energy of 0.1 to 50 kJ and a frequency of not more than 50 Hz, a series of pulses in an amount of 1 to 50, with a duration of at least 5 microseconds to obtain areas with a modified structure of the surface and subsurface layers to a depth of 5 microns to 7 millimeters.

Marking of the product is carried out using an inductor made of metal or alloy, or an inductor with a magnetic field concentrator to reduce the edge effects that occur in the processed product.

Thus, surface treatment is carried out by a high-intensity pulsed magnetic field, as a result of which a code is formed on the surface layer of the product, which is a structure with physical properties different from the base metal, including hardness, electrical conductivity, magnetic permeability and coercive force.

Marking is intended to identify products during production, operation and organization of traceability.

The choice of specific processing modes depends on the specific parameters of the material, chemical composition, size of the treated area and the required depth of the altered structure of the surface and subsurface layers. Thus, when a metal product is treated with a high-intensity pulsed magnetic field, structural changes occur in the surface layer, which leads to a change in the physical properties of the metal, including electrical conductivity, magnetic permeability, and coercive force. The claimed method for marking steel products and alloys based on it is based on this effect.

Local modification of the structure of the surface layers of the metal to a certain depth provides traceability throughout the product life cycle with a relatively simple way of recognizing and reading identification information.

In FIG. 1 shows an experimental sample - a cylindrical inductor with an annular magnetic field concentrator, consisting of the following components:

1. procurement;

2. winding;

3. hub.

The method is as follows.

To form a modified layer on the surface of the product, an inductor or inductor with a magnetic field concentrator of various configurations is used to provide a sharp transition boundary of physicochemical properties between the modified and untreated parts of the product. Electric energy is supplied from an electric energy storage device, for example, a capacitive type, through a controlled electrical switch. As a result of exposure to a high-energy pulsed magnetic field through an inductor, sections with modified surface and subsurface layers of the metal are formed in the metal, having physico-chemical properties different from the base metal, with sizes proportional to the dimensions of the working part of the inductor and concentrator. Additionally, to ensure the calibration of the reader, an inductor with a fixed-size concentrator is used, with which a marker is recorded.

Dimensions marking form, the depth of metal modification is chosen in accordance with the selected form and the content of the recorded information in each case.

To apply the code, an inductor or inductor with a magnetic field concentrator of the appropriate design is used depending on the geometric parameters of the product, the required dimensions of the marking and its depth. For these purposes, for example, a ring inductor can be used for marking by the diameter of the pipe (ring marking). In this case, increased safety of the recorded information in the code with local marking damage will be achieved.

By successive exposure to high-intensity magnetic field pulses, a code is formed in the surface layers of the product with the required information.

The optimal values of the magnetic-pulse processing mode for marking are calculated and experimentally taking into account the chemical composition of the material and the state of processing of which the product is made, the geometric dimensions of the marking elements, the required marking depth (depends on the life and aggressiveness of the medium), the material and geometric inductor parameters by the type and content of the recorded information.

To eliminate the error caused by the influence of external factors (corrosion, mechanical stress, etc.), leading to a decrease in the thickness of the modified zone, an additional calibrated mark is applied, formed by an inductor with a constant-width concentrator.

To read the marking, any of the known methods can be used to determine the change in the physicochemical properties of the modified zones with respect to the main non-modifiable material of the product, for example, measuring the scattering gradient of a magnetic field by a flux-probe control method, using the eddy current method, and a method based on magnetic particle inspection. For marking to be read out, additional magnetization of the marking area may be necessary to produce additional scattering fields.

Example.

A series of experiments was conducted on the local processing of a limited surface area in order to modify the surface layers of the material. As a test sample, we used a cylindrical specimen made of 09G2S steel with a diameter of 20 mm and a length of 100 mm

A cylindrical inductor with an annular magnetic field concentrator was used (see Fig. 1).

The sample was subjected to a single aperiodic pulse of energies of 6 kJ and a duration of 0.5 milliseconds. After processing and exposure at room temperature for 1 hour, the sample was studied by magnetic particle inspection in an applied field. At the interface between the treated and the untreated section, a clear characteristic pattern was obtained that repeats the contour of the ring-shaped portion, while the pattern was slightly wider than the thickness of the ring concentrator.

After this, metallographic studies were carried out with the following results:

- the depth of the modified layer within 100 microns;

- microhardness in comparison with neighboring, untreated areas increased more than 2 times on average and amounted to 1800 kgf / mm2.

Thus, the practical possibility of modifying the surface and subsurface layers of certain sizes and depth in accordance with the selected form and content of the recorded information and which can be easily identified using available methods, for example, based on scattering fields or by the eddy current method, was confirmed.

Claims (2)

1. The method of applying a distinctive marking on the surface layer of a metal product, including local modification of the surface of the product to obtain areas with a changed structure of the surface and subsurface layers, characterized in that the modification is carried out by local magnetic-pulse surface treatment of the product using magnetic pulses generated by the inductor from 1 kA / m to 100 MA / m with an energy of 0.1 to 50 kJ and a frequency of not more than 50 Hz, while 1 to 50 pulses are supplied, duration each of which is more than 5 μs, with obtaining sections with a changed structure of the surface and subsurface layers at a depth of 5 μm to 7 mm. 2. The method according to p. 1, characterized in that the marking on the surface of the product is carried out in an inductor with a magnetic field concentrator, the shape of which follows the contour of the surface area of the product with a changed structure.

Images