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METALWORKING EQUIPMENT METALWORKING EQUIPMENT
AND TOOLS AND TOOLS
a microscope, a computer, a short-length surface, the normal load of a steel ball with a diameter of Dшар = 30 mm is 0.25 N;
reference standard, connecting wires and ● circular speed of rotation of the shaft nвал [rpm];
software (Fig. 1 - 3). ● the circular speed of rotation of the ball nшар [rpm], determined from the relationship nшар
The tribotester is designed to pose the = nвал × dвал / Dшар 1, where dвал is the diameter of the shaft at the points of contact with the
ball and rotate it at a given speed relative to a ball, Dшар 1 is the diameter of the ball section at the points of contact with the shaft;
specified sample with (or without) coating for a
specified test time, as well as for the possibility Table 1. Results of measurements and calculations of testing the substrate.
of reinstalling the sample in order to replace it
or obtain a new print on a specified surface. The measurements calculation
x
x
-5
3
5
x
5
x
-13
main elements of the tribotester are: a base № bipar, μm biperp, μm b, μm Vs 10 , μm 3 Кs 10 , Is 10 , mm/m Ws 10 , μm /s
-
-
with a control panel, a drive shaft fastening m N 1m 1
3
device, an adjustable object table with a vice, 1 654,15 654,15 681,9 7,07 8,96 22,41 0,24
a DC motor, a frequency converter, a counter-
timer, and control elements. The test specimen 2 699,59 699,15
is installed motionlessly perpendicular to the 3 692,01 692,01
plane of rotation of the ball on the supporting
Fig. 2. View of the tribotester after installing the ball. surfaces of the vise jaws. On the control panel ● test time tисп. [c] (taken on the basis of test tests or knowledge of specific coating properties);
of the tribotester, two parameters, which are ● the length of the sliding path of the ball relative to the plane of the sample S = tисп. × nшар
the rotation speed of the drive shaft and the duration of the tests, are set. π•Dшар, where tисп. - test time [min], nшар - ball circular speed [rpm], Dшар - ball diameter [mm].
To visualize the abrasion zone, a monovideomicroscope with a high-resolution zoom The main measured parameters on the print are: bpar, bperp, apar, aperp (Fig. 4).
lens is used, with a holder for coarse and fine focusing, a base, and an object table with The main design parameters for microabrasive wear tests are:
micro-movements. In order to transfer the image of the research object to the computer, a ● for samples of the base material (substrate) without coatings (samples with a coating with an
digital eyepiece USB video camera is used. The image is transmitted from the microscope to a indentation depth less than the coating thickness): volumetric wear of the substrate
computer via a USB cable, where it can be viewed, measured, and also saved as graphic files.
A program for visualizing a microscopic image and determining the geometric dimensions of ,
prints is installed on the computer. or bulky wear of the coating when the indent depth is less than the coating thickness
The main (variable, replaceable) test components are balls and an abrasive suspension.
Balls are mainly used from the production of rolling bearings. Balls material - heat-treated
steel ShKh15, hardness - 60-62 HRC. The parameter of the surface roughness of the balls where R is the radius of the ball used, b is the average diameter of the substrate indentation
is Ra = 0.1 μm. Ball diameter - 30 mm.
As an abrasive suspension, a water-based sample ball bipar and biperp

b = (bipar ср + biperp ср)/2;
suspension with synthetic diamond single
crystals with a diameter of 1 μm (or based ● for coated samples (indentation depth is greater than the coating thickness): volumetric wear
on electrocorundum) is used. During the of the coating
tests, the supply of the suspension to the
friction zone is strictly dosed and repeated [мм3],
in a given time interval.
For measurements, flat samples with a Table 2. Calculation results of MultiPateks coating test on P6M5 steel for average indentation
coating applied to the end surface are used. diameters a = 585 μm and b = 639 μm.
The dimensions of the samples are limited Vs 10 5 Vc 10 5 (Vs+Vc) Kc 10 -13 Ic 10 -5 Wc 10 5 Ks 10 -13 Is10 -5 Ws 10 5 Ics 10 -5 Wcs 10 5
x
x
x
x
x
x
x
x
x
by the dimensions of the jaws of the vice of drive X 10 5
shaft
the tribotester - up to 30 mm in width, up
to 40 mm in length, up to 10 mm in height. Fig. 3. Layout of the sample relative to the ball and drive μm 3 μm 3 μm 3 m N m -1 mm /m μm /s m N m -1 mm /m μm /s mm /m μm /s
shaft
-1
-1
3
3
3
3
3
3
3
3
The recommended roughness parameter
for coated specimens is Ra ≤ 0.32 µm. The
flatness of the end surfaces of the sample should not exceed 0.05 µm. Recommended coating 3,8 1,6 5,5 6,9 5,2 0,05 4,9 12,2 0,13 17,3 0,18
thickness > 1 µm.
The test duration is determined by obtaining the depth of the wear crater greater than the
thickness of the coating. Evaluation of wear parameters is also possible for thick coatings (the Table 3. Calculation results of the TiN coating test on R6M5 steel for medium diameters of
indentation depth is less than the coating thickness) and for a monolithic material, for example, prints, a = 585 μm and b = 639 μm.
a substrate. Vs 10 5 Vc 10 5 (Vs+Vc) Kc 10 -13 Ic 10 -5 Wc 10 5 Ks 10 -13 Is10 -5 Ws 10 5 Ics 10 -5 Wcs 10 5
x
x
x
x
x
x
x
x
x
Constancy of the following parameters is fundamental to the reproducibility of tests: X 10 5
● the angle of inclination of the sample surface to the horizon (about 60 - 75 °), the optimal
position of the ball relative to the drive shaft (the axis of the drive shaft should be parallel to μm 3 μm 3 μm 3 m N m -1 mm /m μm /s m N m -1 mm /m μm /s mm /m μm /s
3
3
3
3
3 -1
3
3 -1
3
the sample surface);
● normal load of a free-lying ball to the surface of the sample N [H], determined by calculation, 9,81 12,01 7,61 15,54 0,16 1,39 3,49 0,04 19,03 0,2
depending on the mass of the specifically used ball, its location relative to the drive shaft and 2,2
the test sample, as well as the coefficients of friction between the ball with the sample surface
and the drive shaft surface. For a specimen located at an angle of 60 - 75 ° to the horizontal
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