SU1235932A1 - Method of hardening parts with shape like body of revolution - Google Patents

Description

1235932

The invention relates to the hardening of the surface using vibration treatment and can be used to increase the cyclic durability of new parts as well as parts recovered by the method of electric arc welding: shafts, fingers, pin and other parts such as rotation bodies.

The purpose of the invention is to increase the cyclic durability and quality.

FIG. 1 shows a shaft reinforcement scheme using an ultrasonic percussion instrument containing five rows of impactors; Fig. 2 shows one of the variants of the location of the impactors, and overlaps the rows of prints when the tool is moved in a direction parallel to the axis of rotation of the part (oi - diameter of the impactor) -, the direction of movement is shown by an arrow; in fig. 3 is a diagram with an indication of the values used in deriving the ratio, which allows to determine the minimum distance between the central and peripheral rows of impactors, starting from the diameter of the reinforced part and the depth of the prints, where D is the part diameter (D 2R), the depth of the prints, left by the impactors of the main row, x is the minimum distance between the main and peripheral rows, ensuring the absence of direct simultaneous contact of the peripheral row impactors with the output end of the ultrasonic transducer and strengthened by the surface.

An ultrasonic percussion instrument containing five rows of percussion bars includes a reinforced part 1, a V-code end 2 of an ultrasonic transducer, a main row of 3 percussion bars, and a peripheral row of 4 percussion bars (percussion bars are shown schematically).

The essence of the invention is that part of the impactors are positioned in a row, which is oriented in a plane passing through the axis of rotation of the part. The remaining impactors, which can also be arranged in rows, are displaced at different distances relative to this main row in the direction of the tangent to the work surface, which is perpendicular to the axis of rotation of the part. The distances from the central row are chosen such that the prints of adjacent drummers or rows at first

five

0

five

0

five

0

five

0

five

moving the transducer in a direction parallel to the axis of rotation of the part overlapped. The minimum distance between the main row and the extreme (peripheral) drummer or a row of drummers, the diameter of the reinforced part and the depth of the prints, determined by the required amplitude of ultrasonic displacements at the output of the converter, are related by

Xi; -sJD E - 6 2,

where X is the minimum distance between the main row of drummers and the extreme drummer or a row of drummers;

D is the diameter of the hardened part; - depth of impact drummer

main r yes.

With this arrangement, the main row of impactors during processing is in direct simultaneous contact with the output end of the ultrasonic transducer on the one hand and the treated surface on the other hand. The treatment they produce hardens the material of the product to the maximum possible depth. Such processing is accompanied by the formation of prints, the depth of which is great and is determined by the amplitude of the ultrasonic vibrations of the transducer and the strength of the material being processed. The surface area thus hardened, moving around the circumference during the rotation of the part, is subjected to successive processing with each next row of strikers and reaches the peripheral row. Moving around the circle is accompanied by an increase in the distance from the area under consideration to the plane of the output end of the converter.

If the distance between the axial and peripheral rows satisfies the above condition, the strikers of the peripheral row cannot be in direct simultaneous contact with the ultrasound transducer and the reinforced surface. In this case, the impulse of force transmitted by the output of the HbDvi end face of the transducer to the impactor is transformed last into inertial displacement towards the surface of the product. Collision with the surface in the absence of direct contact of the transducer - striker - the product is accompanied by its microplastic processing. Intensity of plastic deformation (PD)

in this case, lower than with direct contact processing. The decrease in the PD intensity is mainly determined by the length of the path made by the drummer under the action of inertia. The arrangement of the rows of strikers may be symmetrical with respect to the main row. This allows processing to be performed regardless of the direction of rotation of the part.

The described ultrasonic bombardment of the product and the microplastic processing of its surface provided by it ensure the formation of compressive residual stresses of the surface layer and reduce the irregularities on the treated surface 5-10 times.

Thus, the application of the proposed method allows ultrasonic shock treatment at high amplitudes of ultrasonic displacements at the output of the transducer to achieve a high depth of hardening and compressive residual stresses in the surface layer of the product with a roughness of the processed surface not exceeding R, j (20-40). Ultimately, the application of the present invention provides for an improvement in the cyclic durability of products while reducing time and simplifying the technology of their manufacture.

Example. The shaft of steel 20 with a diameter of 400 mm strengthened by surfacing with 08X20H9C2БТЮ corrosion resistant steel is strengthened. The required depth of the hardened layer is provided by the amplitude of oscillations at the output of the ultrasonic transducer, equal to 20 µm. Hardening at the indicated amplitude leads to the formation of prints 100 μm in depth on the surface of the product (steel 08Х20Н9С2БТЮ).

Option I. In accordance with the recommended ratio, the minimum distance between the main and extreme (peripheral) rows of impactors X D is 6.32 x X 10-3 (i).

For a tool with a symmetrical arrangement with respect to the main arrangement of rows, the minimum distance between two peripheral rows (2x) is about 12.6 mm.

„

35

In terms of design, this case corresponds to a set containing seven rows of impactors with a diameter of 2.0-2.5 mm. 5 Hardening the deposited shaft at a specified high amplitude of movements at the output of the ultrasonic transducer (20 µm) with a set of impactors placed according to the proposed method, with a distance of at least 12.6 µm between the peripheral rows, increases the cyclic strength to a level corresponding to 100- 120% of the cyclic strength of the base metal. The purity of the hardened surface is not worse than R .., 20.

Option II. The processing is performed in the same mode, the set contains three rows of percussion bars, the distance between

20 extreme rows 5.5 mm (differs from the recommended more than twice). The cyclic strength is increased to a level corresponding to the 80% cyclic strength of the base metal. Surface finish R (80-100)

Option III. We reduce the amplitude of the displacement at the output of the ultrasonic transducer to a level of 8 µm, which ensures

JQ sets with one (main) row of impactors, obtaining a surface with a purity of R 20. We perform processing with a set containing one row of impactors. The cyclic strength is increased to a level corresponding to the 60% cyclic strength of the base metal. The technical and economic efficiency of the proposed invention is determined by increasing the cyclic

.. durability of parts subjected to hardening after surfacing and extending their maintenance-free operation, simplifying the technology of manufacturing parts that are hardening in order to increase their cyclic durability and reducing the duration of the production of parts subjected to hardening.

45

The use of the invention in repair facilities will help penniTb the problem of providing a reslesa when restoring the parts used in alternating cyclic loads and corrosive environments to the restoration of welding.

Base 8

FIG. 2

Fiz.Z

Editor I. Derbak

Compiled by A. Kulemin Tehred L. Oleinik

Order 3062/24 Circulation 552Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Proofreader V. But ha

Claims (1)

A METHOD FOR STRENGTHENING DETAILS OF A TYPE OF ROTATION BODIES, including power percussion surface treatment using a set of impactors that are in direct contact with the machined surface and the ultrasonic transducer and moved parallel to the axis of rotation of the part, characterized in that, in order to increase cyclic durability and surface quality, subsequent finishing impact processing using additional impactors oscillating in the gap between the transducer and the surface of the part and offset relative to core projectiles at a distance x 5 -4D6 - £ ² ', where x - the minimum distance to the' extreme additional impactor; D is the diameter of the hardened part; 8 - the depth of the prints of the main drummer. FIG. 1 SU,. „1235932