SU1575099A2 - Method of determining wear-out of metals - Google Patents

Abstract

The invention relates to the field of measuring the wear of metals and can be used in mechanical engineering and instrument making. The aim of the invention is to improve the accuracy of determining wear with prolonged frictional heating. Thermocouples are installed on the surface of the friction of the sample and on the surface opposite to the abraded, as well as on the height of the sample at various distances from the surface of the friction, on the surface subjected to wear and on the surface opposite to the abraded. For each cycle of frictional transfer, temperature distribution curves are plotted along the length of the sample and the areas under these curves are determined over time. After that, the sample's wear during the test period is determined according to the formula, which takes into account the intensity of frictional heating, the heat absorbed by the sample due to thermal conductivity, heat transfer to the environment by convection and radiation. 2 Il.

Description

The invention relates to the measurement of metal wear and can be used in mechanical engineering and instrument making.

The aim of the invention is to improve the accuracy of determining wear in conditions of prolonged frictional heating, taking into account heat transfer by convection and radiation.

Figure 1 shows the results of measuring temperatures at different time intervals; Fig. 2 shows temperature variation curves along the length of the sample.

The method is implemented as follows.

Thermocouples are installed at the surface of friction of the sample and the surface opposite to the abrasionable, as well as at the height of the sample at different distances from the friction surface and at the surface subjected to wear and at the surface opposite to the abraded, thermocouples. time, the measurement results determine the time intervals at which sharp decreases in the temperature difference on the surface of the friction and in the surface layer are observed. Yati areas correspond to frictional transfer cycles

No. 0

sl-h

sl o so

IM

sample material on the counterbody. At the same time, the temperature of the surroundings is measured. For fixed time points with extreme values of temperature differences (maximum and minimum) in the surface layer from the side of the abradable end, for each cycle temperature distribution curves are plotted along the sample length, the areas under these curves are determined. According to the results of temperature measurements, the average temperature differences between the abradable surface and (the surface opposite to the abradable and lateral surfaces are found. Then the wear of the sample during the test is calculated using the formula

xt, 4 l UVcp a (tj) -fc (tj)

& h - 2- V cp tT-tv

at Cg-us +

5b-them;

Ph

9 (t;) and Q (t)

in the surface layer to the test; &h; - surface wear for i

cycles;

& - depth of temperature measurement in the surface layer at the surface opposite to abrasion;

areas under temperature curves

along the length of the sample in mt to the cops of time ti and t;

R; h; S is the perimeter, length, and cross-sectional area of the sample, respectively; 6 — emissivity;

W, 67 JT is constant.

Example, Calculations were performed for the 3 rd cycle of frictional transfer in the period from, 15 s to, 00 when the sample is abraded from the RT material

rial - titanium (b 16.1: C

micron

de fl; WITH;

VCP

bV

for the period from t1. up to t1 /;

with

accordingly, thermal conductivity coefficient, specific heat capacity and sample density; the average temperature difference in the near-surface layers of the abradable surface and the surface opposite to the abradable time is the number of cycles;

- accordingly the average temperature of the friction surface;

- average temperature of the surface opposite to abrasion;

-the average temperature of the side surface of the sample;

-the temperature of the environment over a period of time

from tf to;

i i

And d - 2Gd. - the depth of temperature measurement in the near-surface (abradable) layer;

U, is the distance from the friction surface to the temperature recording point

wed

g

 582 -D; g-; p - 4500 R; Ј- 0.8) L

m

BUT

 0.415 mm; S -Ј- 2.32-10P 1.88 10 2m; th 0.5.

Using experimental data (Figures 1 and 2, the values of all other parameters of the formula were determined.

The total wear of the sample, determined by the proposed method, is uh 0.1 13 mm.

The total wear defined by the prototype method is 138 mm.

From these data it can be seen that over time, the error in determining the wear by the prototype method increases. This is due to the increase in heat transfer by convection, which is not taken into account in the prototype method.

Claims (1)

Invention Formula The method of determining the wear of metals according to the auth. L 1093948, about tl and h aa y and, so that, in order to increase the accuracy of determining wear under conditions of long-term frictional heating, the temperature of the sample at the surface opposite to the abraded one and the ambient temperature using which the amount of heat given by convection - A 6JSLSLГ (at I. II / t, and% IV. + (V & (vcp vc) g wed V.) +  Phi vc) H and the amount of heat given radii Јvo ,, r, РЬ- etc r t Phi -75 K + cf) -rJh in determining wear, is the perimeter, respectively length and area of 15 cross section of the sample; - the average temperature difference between the surface opposite the truth # (gdk Oh d t  R L Ј in raem, a period of time from t; to t; {average surface temperature opposite to abrasion; average lateral temperature of the sample; ambient temperature over a period of time t; to t-; the depth of temperature measurement in the surface layer at the surface opposite to the abradable; emissivity; with L-I W B, o / -yy constant, m to t, t; t, c -la;) - lsi) 95 I g, mm