Трофімов І

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Трофімов І
ISSN 03702197 Problems of friction and wear, 2013, 1 (60)
21
UDC 621.891
M.V. KINDRACHUK1, A.V. RADIONENKO2, V.M. KINDRACHUK3
1
National Aviation University, Ukraine
Pryazovskyi State Technical University, Ukraine
3
Frantsevich Institute for Problems of Materials Science, Ukraine
2
RESEARCH OF WETTABILITY OF FRICTION SURFACES WITH PARTIALLY REGULAR MICRORELIEF
The problems of friction surfaces wettability, lubricating oil running and adhesion depending on the roughness of the surface, the extent of running – in and free superficial
energy of friction surfaces are considered.Technological method of partially regular
microrelief formation on the friction surface is described (PRMR).To control wettability of cylindrical surfaces with partially regular microrelief a technique has been
developed which allows the error effects due to the form of the surfaces studied to be
eliminated.The experimental procedure and the results obtained in the study of the influence of geometrical parameters of partially regular microrelief on the rate of luboil
running have been presented.
Keywords: friction surfaces wettability; partially regular microrelief; rate of luboil
running.
Introduction. Wettability of surfaces, spreading and adsorption of lubricant oil
were studied by Derjaginym B. V, Akhmatov A.S., Zimonom A. D, Fuksom G. I,
Shсhedrovym V. S, Matveevsky P. M., Rebinderom P. A, etc.
By results of researches of these authors it is possible to make generalization:
1. Wettability, adsorption and spreading lubricant oil directly depend on free superficial energy of a firm body which raises with development of imperfections of a
crystal structure at plastic deformation.
2. Essential influence on wetting and adsorption renders a roughness of surfaces.
There are data, that the best wettability of surfaces is observed at the optimum roughness which are being within the limits of parameter of roughness Ra = 0,1 – 0,4 microns. Parameters of microgeometry and their parity also can influence wettability of
surfaces of friction.
3. Spreading lubricant oil on hydrophilic surfaces occurs better in narrower channels or channels to the greater radius and smaller depth.
4. Porosity of surfaces renders positive influence on wetting.
5. After extra earnings of surfaces of friction wettability improves and dynamic
balance between free superficial energy and a condition of a lubricant film is established.
6. Wettability of surfaces of friction can serve as criterion of the termination extra
earnings.
7. Direct influence of wettability on process extra earnings and characteristics of
friction is studied insufficiently. It is not enough works on research of influence of superficial plastic deformation (SPD) on wettability of surfaces lubricant substances. Influence of a submicrorelief on wetting and adsorption is not investigated. Methods of
measurement of wettability of surfaces are imperfect.
8. Speed of self-restoration of a lubricant film at its break can be adjusted due to
wettability which can be operated by means of methods SPD and parameters of microgeometry.
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9. At finishing processing surfaces of friction it is necessary to aspire to maintenance of conditions of the best wetting surfaces due to creation optimum hardening and
an optimum roughness. Optimum hardening and a roughness can be received by methods SPD which is not causing temperature loss of strength a superficial layer by depth
up to 1 micron. It is possible to carry to such methods diamond burnishing, burnishing
spheres in diameter up to 2 – 3 mm, roll forming profile rollers and artificial extra earnings of surfaces of friction.
Statement of a problem. The big number of methods is developed for creation
маслоемких surfaces, to one of which is vibroroll forming [1].
Vibroroll forming – formation on a surface of friction of a grid of microflutes by
means of spherical indenter a method of superficial plastic deformation (SPD). Such
surfaces of friction have received the name “surfaces with partially regular microrelief
(PRMR)”.
The mechanism of boundary greasing of surfaces with PRMR is not studied for
full understanding of processes of friction. The role of wettability of surfaces with
PRMR during friction is not revealed.
Earlier carried out researches of friction and greasing of surfaces with PRMR were
spent without precise differentiation of modes of friction on boundary or mixed lubrication. There are no recommendations on the most effective application of surfaces
with PRMR in the industry at boundary friction.
Presumably, one of mechanisms of lubricant action at boundary greasing of surfaces of friction with it is artificial the created microflutes, is spreading greasings and
its self-restoration. Spreading and self-restoration are caused by forces of a superficial
tension which are created by a power power field of a surface of friction and lubricant
substance. This question was deeply studied with reference to free surfaces of various
firm materials and various liquids. Influence of superficial energy on spreading lubricant oil, on self-restoration of a boundary lubricant film, wettability and adsorption on
surfaces of friction with PRMR is studied insufficiently. The role of wettability of surfaces of friction during extra earnings of these surfaces is not revealed.
The purpose of the given work is revealing a role of wettability of surfaces of friction with PRMR lubricant oil in the mechanism of boundary greasing.
Way of the control of wettability. The way [2] is developed for the control of
wettability of cylindrical surfaces with PRMR, allowing to exclude influence of errors
of the form and a sinuosity of the investigated sample.
The way consists in the following: on an investigated surface of the cylindrical
sample 1 (fig. 1) is imposed matte lavsan a film by 2 thickness 0,1 mm. One end of a
film is fixed, and the second is tightened with constant effort Q. In the center of a film
there is an aperture in diameter of 0,5...1 mm from which axis on an external surface of
a film the uniform grid is put. The dosed out drop of lubricant oil is put on a surface of
a film in a point of an arrangement of an aperture 3 and time is marked.
Lubricant oil gets through an aperture into a backlash formed by ledges of microroughnesses of a roughness of the sample and a film and is sucked in there by capillary
forces of a superficial tension. Due to contact of a film with oil on it distinctly appears
the dark spot testifying to the area spreading of lubricant oil in a backlash between a
surface of the sample and a film in time tspreading. On speed spreading judge wettability
of an investigated surface.
ISSN 03702197 Problems of friction and wear, 2013, 1 (60)
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Fig. 1. A way of the control of wettability of cylindrical surfaces:
1 – the sample; 2 – lavsan a matte film; 3 – a drop of lubricant oil
It is necessary to consider, that the method is relative. The investigated surface
forms a backlash with a film, instead of with the interfaced surface of a detail in pair
friction. The roughness of a film and size of its superficial energy differ from their values on the interfaced surface in pair friction. Therefore it is possible to judge only
change of wettability concerning a surface of a film at research of various surfaces of
samples. Thus it is necessary to provide a constancy of size of superficial energy of a
film, ie. To watch an invariance of its roughness and a degree of pollution adsorbed
pellicles.
Ability of a surface to wettability is defined on speed spreading lubricant oil. That
it is possible to supervise speed spreading in different directions is important: along
forming the sample or it is perpendicular to it.
Speed spreading lubricant oil under a film high, therefore for precise fixing intervals of time and the sizes of the area spreading oils has been applied filming with frequency of 12 staff in a second. Filming was made by a movie camera «Kiev-16U» on
negative film КN-2.
As frequency of the staff in a movie camera size a constant under number of the
staff on a film it is possible to define an interval of time from the beginning spreading
oils under a film and the sizes of a spot spreading. The moment of the beginning
spreading was well fixed on a film on the moment отрыва drops of oil from the end of
a needle of a medical syringe.
On fig. 2 dependences of the sizes of a spot of oil under a film l1 and l2 from time
spreading tspreading and from number of a shot, and on fig. 3 film-grams spreading oils
are shown. Speed spreading is under the formula, as half of size of a spot of oil under a
film l1 or l2 in unit of time (fig. 2).
Research of influence of geometrical parameters PRMR for the speed spreading lubricant oil. It is known, that on size of a corner of wetting and, hence, speed
spreading considerably is influenced with a degree of clearing of a surface from adsorbed pellicles, and, the more cleanly a surface, the this influence is more appreciable.
At presence on a surface of a firm body adsorbed pellicles the size of free superficial
energy caused by a atom-molecular condition of a surface, weakens much more strongly, than the size of superficial energy connected with a roughness of a surface. Therefore in the given experiment at the control of wettability of a surface did not achieve a
high degree of clearing of a surface, and aspired only to reception on investigated surfaces pellicles identical thickness.
For this purpose following preparation of a surface was carried out: double clearing by gasoline, acetone and repeated processing by the cleared gasoline. Then the
dosed out drop of the cleared gasoline in which 20 % of oil Industrialnoe–20 have been
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ISSN 03702197 Problems of friction and wear, 2013, 1 (60)
dissolved was put on a surface. This drop was carried on a surface of the sample on the
constant area. After drying gasoline on a surface there was a uniform thin film of oil.
The film was similarly prepared and lavsan.
Fig. 2. An example of definition of speed spreading lubricant oil VΘ under a film
Fig. 3. Film-gram spreading lubricant oil under лавсановой a film at current time
tspreading
Before studying of influence of the area of microflutes of surfaces with PRMR for
the speed spreading oils have been put the experiment, allowed to compare influence of
a roughness of a surface on size of a regional corner of wetting and on speed spreading
V.
Researches were spent on cylindrical samples in diameter 30 mm. A material of
samples Steel 45 with initial hardness HRC 28-30.
Processing of samples included thin grinding with the subsequent operational development pritirs with the purpose of decrease in errors of the form and a sinuosity.
The size of a corner of wetting on samples without microdeepenings was fixed on
a film at photographing a drop of oil Industrialnoe–20 put on a surface, in two seconds
after отрыва it from the end of a needle of a syringe. Photographing was made at counterillumination that allowed to receive a precise silhouette of a drop of oil on a surface
(fig. 4).
Fig. 4. A drop of oil on a surface of the sample
With roughness Rz = 0,1 microns (a) and Rz = 2,9 microns (b)
ISSN 03702197 Problems of friction and wear, 2013, 1 (60)
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On fig. 5 the schedule of dependence of size of a regional corner of wetting from a
roughness of a surface for annealed samples and for the same samples after finishing
processing, before them annealing is presented. Annealing samples passed in the furnace of mark HLBO SOLO-300 in the environment of nitrogen at temperature 850°С.
The given experiment is set as with the purpose of revealing of influence on wettability of a degree hardening surfaces at various finishing processing samples.
Discrepancy of curves 1 and 2 on fig. 5 speaks that неannealed samples possess
greater superficial energy, than annealed, т. To. Their superficial layer as a result of
finishing processing is riveted, and at annealed samples hardening is removed annealing. But the thin oil film on a surface of samples weakens the size of superficial energy
depending from hardening (atom – a molecular condition of a surface) therefore the
curve 2 comes nearer to a curve 1. This remark proves to be true that the difference in
values of a corner of wetting is more at a roughness nearby Rz = 0,1 microns, ie. In case
of when at finishing processing by polishing rather thin superficial layer hardening is
stronger.
Speed spreading oils was defined on the way described above on the same samples
on whom values of a regional corner of wetting and on samples with PRMR were
measured. Results are presented on fig. 6 and 7.

V ,мм/с
1-отжиг в среде азота,
микротвердость Н=4012 МПа
34
32
30
1
2,0
1,8
28
26
24
F k= 0
2,2
2- без отжига,
микротвердость Н=7130 МПа
F k= 49%
1,6
2
Fk=0
22
20
h k =3,5мкм
1,4
1,2
r k =1,0мм
1,0
0,8
18
16
0,1
0,8 1,0
1,6
Rz, мкм
2,0
Fig. 5. Dependence of a regional corner of
wetting on a roughness of a surface
0,1
0,8 1,0
1,6
2,0
Rz, мкм
Fig. 6. Dependence of speed spreading oils
VΘ from a roughness of a surface
V ,мм/с
1,8
1,6
1,4
1,2
Rz = 0,1мкм
1,0
h k = 3,5мкм
r k = 1,0мм
0,8
0,6
0,4
10
20
30
40
50 Fk ,%
Fig. 7. Dependence of speed spreading oils VΘ from the relative area of microflutes Fk
Results of the control of wettability of a surface on speed spreading V depending on the
relative area of microflutes Fk are presented on fig. 7.
Considering, that size of a regional corner of wetting inversely proportional speeds
spreading VΘ, it is possible to draw a conclusion at comparison of curves on fig. 5 and
fig. 6, that their character is identical. Dependence and VΘ from a roughness of a surface have an optimum corresponding roughness Rz = of 2,0...3,2 microns. This optimum is more obviously expressed on the schedule of speed spreading V and a little bit
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displaced aside a smaller roughness. It speaks that the size of a corner of wetting is
measured on the open surface, and speed spreading - between two surfaces. And, if at
measurement of a corner, wettability is defined by a roughness of one surface at control
V wettability depends and on a roughness of a film which increases size of a capillary
backlash between an investigated surface and a film.
Character of curves allows is equivalent to judge wettability of a surface, both on a
corner, and on speed spreading V, application of a way of the control of wettability on
speed spreading V for surfaces with PRMR therefore is possible.
Increase of speed spreading at increase Fk is caused by faster spreadingм lubricant
oil along flutes VΘk, than on sites between flutes VΘ (fig. 8).
a
b
Fig. 8. The mechanism spreading oils on a surface with PRMR at boundary greasing:
a – spreading from a point A; b – the further spreading from points of crossing of microflutes –
B; VΘК – speed spreading oils along a microflute; V – speed spreading oils on a surface between
microflutes
It occurs only on those surfaces with PRMR at which sites between flutes have a
roughness which is not providing satisfactory wettability. Surfaces of friction of
precision units of the devices working in conditions of boundary greasing at resource
greasing by oils concern to such surfaces. The roughness of such surfaces does not
exceed Rz = 0,8 microns that reduces their wettability and deduction of lubricant oil on a
surface.
In the given work all experiments with use of surfaces with PRMR were spent on
samples with microflutes, the roughness of a bottom and walls which was equal Rz =
0,7...1,2 microns. The roughness of a bottom and walls directly after their formation by
method SPD is not more rough than microflutes Rz = 0,5 microns. The difference in a
roughness is connected by that at operational development of samples by diamond
paste the roughness of a bottom and walls microflutes worsened. It affected and speed
spreading oils. It has noted been, that greasing spreads worse on flutes of the samples
who have been not last operational development with diamond paste.
Spreading oils on a flute occurs owing to presence of a corner (fig. 8). The less
size of a corner, the above speed spreading.
The best wettability of surfaces with PRMR in precision units of friction with
highly smooth surfaces speaks origin of the new centers spreading a liquid lubricant in
points of crossing of flutes (a point In, fig. 8). Such points of crossing are characteristic
for PRMR II and III kinds [1], (GOST 24773-81). The conclusion that surfaces of friction with PRMR II and III kinds provide the best spreading greasings From here follows and create more favorable conditions for the mechanism of greasing and process
of friction. It proves to be true results of many researches which have confirmed optimality PRMR II and III kinds at boundary greasing [1, 3].
ISSN 03702197 Problems of friction and wear, 2013, 1 (60)
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Conclusions. The developed way of the control of wettability of surfaces has allowed to estimate speed spreading lubricant oil on surfaces of friction with partially
regular microrelief and, hence, speed of self-restoration of the lubricant boundary film
broken off at friction. Data about speed spreading lubricant oil depending on a roughness of a surface and from the relative area of microflutes Fk of surfaces with PRMR
are obtained.
Results of experiments have confirmed, that on surfaces with PRMR II and III
kinds speed of restoration of a lubricant film above, than on surfaces of friction without
microdeepenings. It will be coordinated with results of tests of surfaces of friction at
boundary greasing [1]. Researches have shown, that is possible is equivalent to judge
wettability of a surface, both on a corner, and on speed spreading V, application of a
way of the control of wettability on speed spreading V for surfaces with PRMR therefore is possible. Positive influence of wettability of surfaces with PRMR on process of
friction in conditions of boundary greasing is shown on высокогладких surfaces of
precision units of friction with roughness Rz 0,8 microns.
It is established, that with increase in the relative area of microflutes Fk at constant
width of a microflute bk, wettability of a surface with PRMR improves.
The best wettability surfaces with PRMR II and III kind possess. It speaks presence of the big number of the centers spreading, being in points of crossing of microflutes among themselves. Spreading oils and self-restoration of a lubricant film on a
surface of friction with PRMR occurs better in microflutes to the greater radius and
smaller depth. The more the radius and is less depth of a microflute, the the corner (fig.
8) and above speed spreading is less.
The list of the literature
1. Шнейдер Ю.Г. Эксплуатационные свойства деталей с регулярным
микрорельефом. – Л.: Машиностроение, 1982 – 248 с.
2. Способ определения маслоемкости поверхностей трения: А. с. 985549 СССР, МКИ
F 16 N 29/02// G 01 N 11/ 00 / А.В. Радионенко (СССР) - № 3321642/25 – 08; Заявл.
20.07.81; Опубл. 30.12.82, Бюл. № 48. – 110 с.
3. Радиненко А.В. Модель трения поверхностей с частично-регулярным
микрорельефом и их технологическое обеспечение / А.В. Радиненко, М.В. Кіндрачук //
Проблеми трибології. – 2005. – № 1. – С. 59-68.
Article received on 04.06.2013
М. В. КІНДРАЧУК, О. В. РАДІОНЕНКО, В. М. КІНДРАЧУК
ДОСЛІДЖЕННЯ ЗМОЧУВАНОСТІ ПОВЕРХОНЬ ТЕРТЯ З ЧАСТКОВО
РЕГУЛЯРНИМ МІКРОРЕЛЬЄФОМ
Розглянуті питання змочуваності поверхонь тертя, розтікання і адгезії мастильної олії залежно від
шорсткості поверхні, від міри прироблення і від вільної поверхневої енергії поверхонь тертя.
Описано технологічний спосіб утворення на поверхні тертя частково регулярного мікрорельєфу
(ЧРМР).
Ключові слова: змочуваність поверхонь тертя, частково регулярний мікрорельєф,
швидкість розтікання мастильної олії.
Kindrachuk Myroslav Vasilyevich – Dr.Tech.Sc., professor, Head of Engineering Department of National Aviation University, [email protected]
Radionenko Alexander Vasilevich – Cand.Tech.Sci., the senior lecturer of faculty of
technology of mechanical engineering of Pryazovskyi State Technical University, Mariupol.
Kindrachuk Vitaly Miroslavovich – Cand.Tech.Sci., doctoral student of Frantsevich Institute for Problems of Materials Science.

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