SU1655997A1 - Method for improving inner surface of hollow products - Google Patents

Abstract

The invention relates to metallurgy, specifically to the processing of pipes by surface plastic deformation. The purpose of the invention is the expansion of technological capabilities by processing long pipes. The method consists in the fact that an ultrasonic waveguide enters the tube from one end and a rod having a sphere-shaped end at the other end, while they are located at a distance between their ends, a multiple of A / 2, where A is the ultrasound wavelength in the air. Steel balls and alloying element powder are placed in the gap between the ends. Ultrasonic vibrations are turned on, and the tube is transmitted in translational motion at a velocity V (r0 Imfo) 2 Vp / ff Q, 2n / Jl Ro (3Ro + -2fn A / 2), where r0 is the radius of the balls; p is the density of their material; Иt and f0 are the displacement amplitude and oscillation frequency of the free end of the waveguide; then, 2 is the yield strength of the pipe material; RO is the radius of the pipe; m 1, 2, 3, ... is an integer; n is the number of balls. Using the method allows to significantly increase the wear resistance of pipes. 1 il. Yo

Description

The invention relates to metallurgy, specifically to the processing of metals, and alloys by surface plastic deformation in the manufacture of long pipes.

The aim of the invention is the expansion of technological capabilities by processing long pipes.

Example. The inner surface of the pipe with a diameter of 30.0 mm (radius R0 15.0 mm) and a length of 1500 mm of ZOHN2MFA steel was machined.

The drawing shows the installation diagram

Indicated in the drawing; 1 - ultrasonic generator UZG-2-4M; 2 - magnetic striction transducer

PMS-15A-18; 3 - step concentrator made of VTZ-1 alloy; 4 - ultrasonic wave guide; 5 - cylindrical rod; 6 - product (pipe); 7 - working chamber formed by the pipe walls and the ends of the rod and the waveguide, with steel balls and powder of the alloying substance; 8 - a moving carriage, fastened with a pipe; 9 - carriage guide; 10 - mechanical switch of the generator UZG-2-4M; 11 - bed; 12 - electrodynamic sensor; 13 - voltmeter B7-34 for

I ate with you

Xi

registering the hub displacement amplitude; 14 - frequency 43-44 for recording the frequency of oscillation of the system.

Steel balls and a powder of the alloying element, an ultrasonic waveguide 4 and a cylindrical rod with a spherical end are placed into the internal cavity of the pipe (working chamber 7).

The inner surface of the pipe is processed using ultrasound, whereby the pipe is transmitted in translation relative to the waveguide and the rod at a speed

y - (Go gm fo j2 Vp / Cfr, 2 Lm

 7rRo (3Ro + 2mA / 2) UJ

where r0 is the radius of the working bodies;

p is the density of their material;

| t and f0 are the displacement amplitude and oscillation frequency of the free end of the waveguide;

n is the number of balls;

sgo, 2 is the yield strength of the pipe material;

RO is the radius of the pipe.

m 1, 2, 3, ... is an integer.

Placing the powder of a molybdenum disulfide or molybdenum carbonyl alloying element into the working chamber can significantly increase the resistance of the pipe due to the mass transfer of the atoms of the alloying element to the depth of the pipe material when the balls hit the inner surface.

The manufacture of a rod end in the form of a hemisphere contributes to the dispersion of balls in all directions and thereby ensures uniform hardening of the inner surface of the pipe.

The location of the ends of the rod and waveguide at a distance that is a multiple of I / 2, where I is the wavelength of ultrasound in air, provides a resonant mode in the air column of the working chamber and, as a result, the appearance of acoustic fluxes and radiation pressure. These factors significantly intensify the hardening process.

The movement of the tube relative to the waveguide and the rod with a certain speed (1) allows you to evenly process the entire inner surface of the tube

The processing of the pipe was carried out according to the following parameters: the oscillation frequency was up to 20.0 kHz, the displacement amplitude Јt - 100 µm, the density of the material of the balls was 7.8 g / cm, their diameter was 1.0 mm (radius r0 0.05 cm). The ultrasound wavelength I is 1.84 cm. The rod and the waveguide were installed at a distance between the ends of I I / 2 1.84 cm (i.e., m - 1). The radius of the sphere butt rod

was 1.5 cm. The yield strength of the material of the pipe steel ZOHN2MFA was Hundred, 2 120 kgf / mm. Number of balls h 1000 pcs.

5Thus, the speed with which the pipe must move is

7,8rcMJ

(15 g - o11 / sЈ At Tsp1uЈ; 10 3.14 1.5 cm (4.5 cm + 1.8 cm)

10; cmУs2 -2.5 10 s / cm 103 4.5 6.3 cm2

: 0.1 cm / s.

For processing the whole pipe,

time - -1500 with 25 min.

If the speed of movement is less than V, then the surface is over-stuck, and if the speed of movement is greater than V, then the surface will not be completely riveted. With

In this way, the wear resistance of the steel is reduced.

Pipes were also processed by

prototype method (placing balls and

ultrasonic waveguide into the inner

tube cavity and sonication (npH.f0 20.0 kHz, t 100 µm, I 1.84 cm).

Comparative tests showed that after processing by the proposed method, the wear resistance of pipes increased by 1.2 - 1.5 times compared with the processing by the method prototype. Using the proposed method makes it possible to harden the inner surface of the through long pipes.

Claims (1)

The invention The method of hardening the inner surface of hollow articles, mainly pipes, including the processing of internal the surface of the pipe with the help of steel balls driven by an ultrasonic waveguide, which is a free end in the cavity with a gap between the waveguide and the cavity balls diameter, characterized in that, in order to expand technological capabilities by processing long pipes, at the same time as hardening, doping is carried out when placing the powder in the cavity, and the treatment is carried out by introducing into the tube from the side opposite the waveguide a rod with a diameter that coincides in the inner diameter of the tube, which has a spherical end surface with a sphere radius that coincides with the radius of the inner surface of the tube and is located at a distance , multiple I / 2, where I is the wavelength of ultrasound in the air, at the same time the pipe is reported to move forward relative to the waveguide and the rod with a speed (V) V - (ro-Јni fo) Vp / Ogan ° 7TRo- (3R0 + 2m-А / 2) where r0 is the radius of the working bodies; p is the density of their material; Иt and f0 are the displacement amplitude and oscillation frequency of the free end of the waveguide; 7o.2 - yield strength of the pipe material; RO is the radius of the pipe; . n is the number of balls; m 1, 2, 3, ... is an integer.