WO2007015688A1

WO2007015688A1 - Method for ultrasound vibro-impact processing of long-length product surface

Info

Publication number: WO2007015688A1
Application number: PCT/UA2006/000049
Authority: WO
Inventors: Georgij Ivanovich Prokopenko; Aleksandr Fedorovich Lugovskoy; Varlerij Ivanovich Chornyj; Andrey Valerievich Movchanuk; Jakob Isakovich Kleiman; Yuriy Filipovich Kudryavtsev
Original assignee: Georgij Ivanovich Prokopenko; Aleksandr Fedorovich Lugovskoy; Varlerij Ivanovich Chornyj; Andrey Valerievich Movchanuk; Jakob Isakovich Kleiman; Yuriy Filipovich Kudryavtsev
Priority date: 2005-08-01
Filing date: 2006-07-28
Publication date: 2007-02-08
Also published as: UA79670C2

Abstract

The invention relates to a method for vibro-impact processing of long-length product surfaces and can be used for mechanical engineering, mainly for finishing long-length metal products, in particular wire, pipes and other articles producible by drawing and rolling. The processing is carried out with the aid of a set of ultrasound converters provided with tools placed along the product path direction, the relative positioning of said tools is determined by the product shape and the number thereof is determined by a required number of impacts per a surface unit at a specified speed. The amplitude of sound oscillations and a pressing force are selected according to the plastic deformation degree of the product surface. Said invention makes it possible to increase the processing speed at a specified quality and stability thereof and to increase the fatigue and corrosion resistance thereof.

Description

IPC B24 V 39/00, 1/04

Method for ultrasonic vibroimpact surface treatment of long products

Technical field

The invention relates to the field of engineering, in particular to the finishing of long metal products, and can be used in the finishing of wire, pipes and other products obtained by drawing, rolling and other methods.

State of the art

Surface strain hardening of metal products, as a final technological operation, significantly increases the efficiency of parts and machines, increases their quality and service life. Today, methods of surface treatment using plastic deformation, such as treatment with balls and rollers, bead peening, vibro-rolling, and others, are widely used. The interest in high-energy types of surface treatment, which includes surface hardening using ultrasonic vibrations, has significantly increased in industry. The test results and operating practice show that when processing products from metal materials, especially high-strength, the ultrasonic method is quite effective and easy amenable to automation. The industry produces a large range of long products of different profiles and cross sections: wire, cord, pipes, strips, etc., which are formed using pressure. As a rule, tensile residual macrostresses are formed in the surface layer of such products, which reduce fatigue strength and corrosion resistance. In this regard, there is a need to create new methods of ultrasonic treatment for hardening and redistribution of residual stresses in long products, drawing and drawing of which is carried out with high speeds. The performance and quality of the ultrasonic treatment process depend on the choice of loading scheme and the optimal operating mode of the ultrasonic tool.

A known method of ultrasonic non-abrasive processing (A.S. USSR W 1278182, IPC B24B 1/04, 1986), in which the working surface of the tool is pressed against the work surface and they are moved relative to each other, characterized in that the tool is informed by bending vibrations and placed it at an angle β in the direction of surface treatment, and the angle is set in the range 0 <β <α, where α is the amplitude of the bending vibrations of the tool face (in angular units).

The known method has low productivity due to the use of a single tool that processes a narrow strip limited by the contact point. Use bending vibrations that are easily damped by the load, leading to a significant decrease in the amplitude of oscillations during processing. Excitation of longitudinal ultrasonic vibrations (along the direction of movement) leads to intensive wear of the surface layer, which reduces its quality.

A known method of non-abrasive ultrasonic surface finishing (Russian patent P 2127658, IPC B24B 1/04, 1999), in which the surface treatment is carried out by moving the working surface of an acoustic instrument at all points on the surface of a complex profile of the workpiece, and the part is rotated during processing. The acoustic system is fixed with the possibility of rotation by an angle of ± 45 ° relative to the axis of the part.

However, this method has a low productivity due to a long scan of the surface of the product, which also leads to uneven processing. The location of the acoustic instrument at different angles to the surface of the product creates conditions for intensive abrasion of the surface layer, which affects the quality of processing and increases the roughness.

The closest to the proposed method for the combination of features and technical result is a method of ultrasonic non-abrasive surface treatment (a. With. USSR EP 1821342, IPC B24B 39/00 1/04, 1993), in which the working tool is pressed to the surface of the workpiece and inform them moving relative to each other, while the worker rotational movement is reported to the tool, and the force of pressing the tool to the work surface is selected so that the depth of the working tool into the surface exceeds the thickness of the oxide film with an amplitude of ultrasonic vibrations of 5-10 μm.

However, this method has significant disadvantages, including low productivity due to the forced rotation of the working tool to cover the entire work surface. Deepening the working tool into the surface and creating lateral displacements to the deepening leads to intensive abrasion of the surface layer, which contributes to its transition into wear products. All this increases the surface roughness, leads to uneven microhardness and depth of processing and, ultimately, to a decrease in its quality and productivity.

Disclosure of invention

The basis of the invention is the task of developing a method of ultrasonic vibroimpact surface treatment of long products, in which an ultrasonic transducer with working tools is pressed with normalized force to the surface of the product and the latter is informed about the movement relative to these tools, the processing is carried out by a fixed set of tools placed along the line of movement of the product, their mutual the location is determined by the profile of the lengthy product, and the number is determined by the number of strokes per unit per erhnosti at a given Velocities, the amplitude of ultrasonic vibrations and the pressing force are selected according to the criterion of the degree of plastic deformation of the surface of the material of the product in order to increase the processing productivity at a given quality and stability.

To solve the problem in a method of ultrasonic vibroimpact treatment of the surface of long products, in which the ultrasonic transducer associated with the working tools is pressed normalized to the surface of the product and tells them to move relative to each other, according to the invention, the processing is carried out by a set of ultrasonic transducers placed along the line communicated with the product moving and according to its profile in the amount necessary for applying to a unit surface of the product specified by the technologist and the number of strokes, the amplitude of ultrasonic vibrations and the pressing force are selected according to the criterion of a given degree of plastic deformation of the surface of the product, and the speed of movement V is associated with the processing parameters by the ratio:

V <f-L-p, where f is the average oscillation frequency of the working tools; L is the size of the output end of the working tool along the line of movement; p - the number of working tools along one processing line.

The problem is also solved by the fact that to the surface of the product opposite the main working tools elastically press additional. The problem is also solved by the fact that in the contact zone of the working tools with the surface of the product serves lubricating and cooling body.

Processing with working tools placed depending on the profile of the lengthy product along the line of movement normal to the surface and at an angle relative to each other, allows impact deformation to simultaneously cover the entire surface of the product that moves at a certain speed. If the product profile is round (bar, wire), then the tools in the proposed method are placed at equal angles relative to each other to cover the entire surface, and if the profile, for example, is flat (strip), then the working tools are placed perpendicular to the surface in several rows with offset between them by a certain interval. The elastic clamping of the working tools to the end face of the ultrasonic transducer and the product creates reliable acoustic contact between the product and the tools and thereby ensures that the product is processed with all the tools - basic and additional. This increases the productivity and quality of processing the entire surface of a lengthy product without gaps that may occur if there are uneven surfaces of the product. As shown by experimental verification, the quality of ultrasonic vibration processing increases with an increase in the number of strokes per unit area. At the same time, with an increase in the pulling speed, its effectiveness decreases. For, in order to increase the productivity of the process, the number of ultrasonic transducers (and, accordingly, working tools) along one processing line is increased. The oscillation amplitude of the ultrasonic transducer is selected depending on the strength of the material of the product so that during processing there is no significant change in the cross section of the product. Thus, the surface treatment is carried out sequentially with an increase in the number of strokes per unit area as the lengthy product is pulled along several groups of ultrasonic transducers with the corresponding set of working tools - percussion instruments. The fulfillment of the condition (V <f-L'n) allows it to be processed uniformly without gaps along the entire length. If we assume that the product f> L is constant, then the speed of broaching the product is directly proportional to the number of tools along one line.

For some types of processing, for example, to relieve residual stresses in a thin wire, there is no need to apply a large number of impacts per unit area with plastic deformation of the material itself to create compressive stresses. In these types of processing, as shown by experiments, it is enough to strike with gaps at a speed of movement of the product V> f * L'P. The energy of each impact during such processing excites elastic vibrations in the product itself. These vibrations propagate at a certain speed along the product over long distances, causing reduction of residual stresses as in conventional vibration processing.

Brief description of the method

The invention is explained by illustrations, where Fig. 1 shows a kinematic diagram of a method; figure 2 - kinematic diagram - view along the line of the broach; Fig. 3 - ultrasonic transducer with a working tool; figure 4 - scheme of processing the product in the form of a strip; figure 5 - layout of ultrasonic transducers; in FIG. b - an ultrasonic transducer with basic and additional working tools that are pressed against the surface of the product by a spring.

In Fig. 1, ultrasound transducers are pressed with a force P to a long product 1, which moves in the same direction at a speed V, which are assembled in three groups 2. In the group, the transducers are placed along one of the parallel lines along the product axis, and each group (3 , 4,5) is located at an angle α relative to each other (figure 2). Thus, each group of converters placed in a row processes its linear section of the product.

In Fig. 3 shows a diagram of an ultrasonic transducer, which consists of a composite piezoelectric transducer 6 with an oscillating velocity transformer (TKC) 7. The working tool 8 has a groove 9 corresponding to the profile of the product 10, and pressed against it with a total force P. On the opposite side of the product is bearing 11. Fig. 4 shows the case when the lengthy product has a strip profile 12. In this case, four groups 13 of ultrasonic transducers are pressed perpendicularly to the surface 14 through their working tools, and the support 15 has a guide groove on a flat surface across the width of the product. Each group 17 contains several working tools located along the processing line, covering in total the entire surface 14.

In Fig. 5 shows a fragment of the surface of the product, which moves at a speed V past two groups of working tools 16 connected to ultrasonic transducers 17 and 18. Each tool has a linear dimension L in the direction of movement. They are located at a distance h from each other within the same ultrasonic transducer. Ultrasonic transducers 17 and 18 are placed at a distance t. On the surface of the product shows the prints 19 of the three instruments of the ultrasonic transducer 17 and the following three prints 20 of the instruments of the ultrasonic transducer 18.

Figure 6 shows an ultrasonic transducer with an attached TKC 7. Here, the product in the form of a wire 10 is clamped by means of a spring 21 between the main working tool 22 and the additional working tool 23 located opposite. The spring 21 rests its second end against the bottom of the cup 24, which is fixed with its edges in the nodal plane of the speaker system 25.

Embodiments of the invention The principle of operation and the sequence of operations to implement the proposed method can be illustrated by the example of the circuit shown in Fig.l. In the process, a lengthy product 1, for example, a wire, is stretched in one direction (linearly or possibly screw movement) at a speed V past groups of stationary ultrasonic transducers 2 mounted at a certain angle to each other. The piezoceramic transducer β excites longitudinal ultrasonic vibrations, which are amplified by TKC 7 (FIG. 3). The end face TKC oscillates with a frequency of 22 kHz and the energy of these vibrations is transmitted due to the impact interaction of the working tools 8. The energy of the impacts of these tools is spent on deforming the surface of the wire 1 in the region of the groove 9, their elastic rebound and on exciting vibrations in the wire. In this case, the average frequency of vibration impact of tools on the product is significantly lower than the ultrasonic one, and is approximately 1-3 kHz. The amplitude of ultrasonic vibrations is chosen quite low (~ 5 - 10 microns). At the same time, due to the reaction of the support 11, counter vibratory impact deformation of the wire occurs in the region of the guide groove.

Since the working tools vibrate only in the direction perpendicular to the surface of the wire, there is no removal or removal of its thin surface layer. Normal Vibration Shocking Leads to Surface Hardening _{γ χ}

wire, reduce and favorable redistribution of residual stresses from tensile to compressive, as well as to reduce the roughness of the surface layer.

To obtain high quality and stability of surface hardening, it is necessary to achieve a uniform distribution of impacts of all working tools both along the product profile and along its length. The uniformity of processing along the profile is achieved by the symmetrical arrangement of the working tools over the cross section, so that each hit of an individual tool falls on an unprocessed portion of the surface of the product that follows the processed one! If the size of the output end of one tool in the direction of movement is L (Fig. 5), then at a frequency of oscillations f, the speed of movement of the wire should be V = f'L. Then the tool 16 will make prints on the surface of the product close to each other. To increase processing productivity with increasing draw speed V, several impact elements 16 are pressed against one end of TKC 17, for example, three (Fig. 5), each of which has dimension L in the direction of movement. The tools are placed from each other at a distance h, which is selected less than size L. During processing, if the dynamic characteristics of the tools are identical, they will simultaneously make three prints 19, which are located at distances h (Fig. 5). This is equivalent to a three-fold increase in size L (in accordance with the number of tools), which confirms the above the ratio V = f * Lti, where: n is the number of tools along one processing line.

If a second identical ultrasonic transducer 18 is installed at a distance t (Fig. 5), then its tools will make similar prints and the speed V can be doubled. In other words, each tool makes consecutive hits on the surface of the product, and plastic prints when pulling the wire are folded into one continuous strip without gaps. If the speed is greater than the specified one, then some parts of the product surface will remain without prints, if less, then the processed surfaces will mutually overlap.

One of the ways to reduce residual stresses is the so-called vibration processing. The impact of working tools causes the excitation of elastic vibrations in the wire. To carry out such processing in the proposed method, it is sufficient to use a smaller number of tools at a product moving speed of V>f> Ln. However, the combined effect of surface plastic deformation and vibration processing can lead to a more significant positive effect. By changing the amplitude of the oscillations of the ultrasonic transducers, their number, the angle of inclination relative to each other, as well as the clamping force P, at a given speed of drawing, you can choose the optimal processing mode to obtain the desired technical result. When processing the product with the main and additional working tools 22, 23 (Fig.6), placed against each other, the latter can change the direction of impact due to random turns around the axis of the ultrasonic transducer, which leads to strikes on the product profile at different angles. The dashed lines in Fig. 6 show the possible inclination of the working surfaces of the tools during processing. In this case, the guide groove in the working tools 22, 23 can have a significantly larger radius than half the diameter of the product 10. According to this scheme, it is possible to process wire of various diameters.

Since there is a small frictional force between the wire 10, the tool 8 and the support 11 (Fig. 3), a certain amount of heat will be generated at the contact points as a result of high-speed pulling. Particles of contamination will also be present in this area due to scale degradation or the appearance of wear products. Therefore, to stabilize the thermal regime and remove wear products, a lubricating and cooling body (liquid, air) is additionally introduced into the contact zone of the working tools with the surface of the product.

An example.

A device was implemented according to the proposed method for processing steel cord with a diameter of 0.8 mm in the delivery state after cold drawing. Ultrasonic transducers had a resonant frequency of 22 kHz. They were installed in three rows of 3 pieces at an angle of 60 ° relative to each other. Each ultrasonic transducer contained 4 working tools and was pressed against the product with a force of about 10 H. The instruments had a diameter of 5 mm and a broaching speed of 3 m / s. This arrangement of the device provided uniform processing of the cord surface with a sequential increase in the number of strokes per unit area with an amplitude of oscillation of the end face of the TKC ultrasonic instruments 10 + _ 1 μm. In this case, the degree of plastic deformation of the cord material corresponded to a predetermined one according to the technology (about 1-2%). The selected treatment mode ensured an increase in the endurance limit of the cord during fatigue bending tests by an average of 30% compared with the initial state.

Claims

Claim

1. The method of ultrasonic vibroimpact treatment of the surface of long products, in which the ultrasonic transducer associated with the working tools is pressed normalized to the surface of the product and tells them to move relative to each other, characterized in that the processing is carried out by a set of ultrasonic transducers placed along the line communicated with the product moving and according to its profile in the quantity necessary for applying to the unit surface of the product the number of strokes specified by the technology, the amplitude trazvukovyh vibrations and the pressing force is selected by a predetermined criterion degree of plastic deformation of the product surface, and the moving speed V is associated with parameters ratio of processing:

V <f-L-n, where f is the average oscillation frequency of the working tools; L is the size of the output end of the working tool along the displacement path; p - the number of working tools along one processing line.

2. The method according to claim 1, characterized in that additional ones are elastically pressed against the surface of the product opposite the main working tools.

3. The method according to p. 1-2, characterized in that in the contact zone of the working tools with the surface of the product serves lubricating and cooling body.