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As seen from tables 1 and 2, the tests carried out by us for abrasion wear with samples of coating thickness of 2.5-3.0 mm were completely consistent with the results of field trials, which do increase performance and durability ofmolded parts oftillers after heat treatment with dual phase recrystallization to two or three times.
Heat treatment affects not only wear resistance of surface, but the subsurface layers of hard-alloy coatings. This is important for a number of parts of tillers, where the wear limit can be about one millimeter. When comparing wear resistance of specimens with hard-alloy coatings before and after heat treatment it can be found that the effect of this treatment on the layer depth is increasing from 7% at the depth of 0.6 mm to 90% at the depth of 1.4 mm.
The technologies of application ofhard-alloy coatings in molding based on consumable patterns and subsequent thermal treatment with double phase recrystallization developed by us were used in production of an experimental batch of cast parts and tested under field conditions in different regions of the country. Field
test results have shown that the wear resistance of cast steel parts with hard-alloy coating without heat treatment, compaction stability and increase in wear resistance of 2.2-2.6 times, and after heat treatment with dual phase recrystallization are 3.0-3.5 times higher than that of commercially available products [8; 9].
Conclusions. Thus, it can be concluded that the effective way to increase the abrasive wear resistance is to apply wear-resistant hard-alloy coating with molding based on consumable patterns to operating surfaces of the products. Heat treatment hard-alloy coating of high-chromium alloy carried out with double phase recrystallization, is forming optimal structure of high-density dislocation, disperse and secondary coagulated primary carbides. The data submitted show that heat treatment ofhard alloy coating with a double phase recrystallization increases the efficiency and durability of finished castings in three or more times. The developed technology was implemented in production of «Metallmexqurilish» HK and «Uzmetkombinat» JSC with a good economic effect.
References:
1. Mavlyanov N. M. Improving reliability of the working bodies and quality ofpresowing and sowing machine-tools. - Tashkent: Mehnat, 2000. - 462 p.
2. Tilabov B. K., Mukhamedov A. A., Islamkulov K. M. Getting hard-alloy wear-resistant coatings on operating surfaces of machine parts//Bulletin (Khabarshysy) of the International Kazakh-Turkish University named after K. A. Yassavi. Turkestan. - Kazakhstan. -№ 3. 2004. 21-24 p.
3. Mukhamedov A. A. Effect of heat treatment on the wear parts with hard-alloy coatings. Monthly scientific-technical and industrial journal//Physical metallurgy and heat treatment of metals. MiTOM. - Russia. 2003. - № 3. 29-31 p.
4. Tkachev V. N. Depreciation and increase of durability of working organs of tillers. - M.: Engineering, 1996. - 293 p.
5. Tilabov B. K. The wear resistance of melted hard alloy of PG-C27 type with metastable austenite and martensite. Republican Inter-university collection of scientific papers. "Current issues in the field of technical and socio-economic sciences". - Tashkent: Issue 1, 2011. 359-362 p.
6. Skakov Y. A. Crystallography, X-ray and electron microscopy. - M: Metallurgy, 2010. - 632 p.
7. Tenenbaum M. M. Resistance to abrasion. - M.: Engineering, 1996. - 267 p.
8. Mukhamedov A. A. Heat treatment with double phase recrystallization for improving service properties of machine parts and tools//Heat treatment and technology of surface coating. Materials of the Congress. Vobume v. MOTO. December 11-14. - Moscov, 1998. P. 38-39.
9. Tilabov B. K. Increase the service life of cast parts tillihg machines. International Conference «Global Science and Innovation» March 23-24, 2016. USA. Chicago, 2016. C. 222-225.
Baymetov Rustam Isayevich, Scientific research Institute for mechanization and electrification of agriculture, Doctor of technical science, Professor, the chief of laboratory
Astanakulov Komil Dullievich, Scientific research Institute for mechanization and electrification of agriculture, Doctor of technical science, Senior scientific employee, the chief of laboratory
Fozilov Golibjon Gulomjonovich, Scientific research Institute for mechanization and electrification of agriculture, Scientific employee, laboratory of cereal harvesting machines, Uzbekistan,
E-mail: [email protected]
Results of the done theoretical research for choosing the type of hole of the corn sheller sieve and determining its useful area coefficient
Abstract: In the article results of the done theoretical research are illustrated which are about choosing the type of hole of the corn sheller machine sieve and determining its useful area coefficient. Keywords: corn, pith, husk, grain, corn sheller, sieve, types of the hole.
Nowadays, requirement is increasing for grain of the corn in Uz- to harvest the corn for grain. According to above written problem, a bekistan. However, farmers are coming face to different difficultness new type corn sheller machine was created at scientific research In-
stitute for mechanization and electrification of agriculture of Uzbekistan and it is being developed for modern requirement [1].
When an experimental sample of the corn sheller was tested, results were that threshing efficiency was 99.4 per cent, damaging of the grain was 0.9 per cent, cleaning efficiency of the grain was 99.2 per cent, above written indexes answer to the requirement. However, it was known that the amount of the grain which was coming through pith and husk outlet of the corn sheller included 4.7-5 per cent [2].
For the purpose to prevent the defect of the corn sheller machine we researched and found technical solution [3]. According to the done research, the sieve was installed opposite of pith and husk outlet of the corn sheller, every hole's size was 15 mm.
The technological process of the corn sheller sieve is difficult for separating the grain from pith and husk, the grain must be separated from pith and husk by sieve's hole, pith and husk must not be gathered on surface of the sieve and it must be provided that, the grain must be separated also pith and husk must fall down from sieve on time during work process.
According to above written work process, for increasing ofwork efficiency of the sieve the hole type must be selected correctly and fixed up also it is demanded that, the coefficient of the useful area of sieve should be determined according to the selected holes.
The main constructive parameters of the sieve are width of the sieve BS, its length LS and the area of the sieve holes SH. The number of the holes and their position influence straightly to the work efficiency of the sieve. The quantity of the holes is characterized with coefficient of the useful area of sieve ^ and it depends on the area of the all holes F0 also the total area of the sieve F and it is determined by following formula [4]:
" (1)
here F0 — an area of the all sieve holes, m 2;
F — a total area of the sieve, m 2;
^ — a coefficient of the sieve useful area.
An area of the all sieve holes F0 is determined by the following formula:
f = nn.h ■ sa.h, (2)
here Nnh — a number of the all sieve holes, piece;
SA H — the area of the one hole, m 2.
For choosing the type of hole of the corn sheller sieve at first we counted by circle form holed sieve (figure 1).
Figure 1. The scheme of the circle formed hole sieve According to figure 1, SAH in the (2) is equal to following formula for circle holed sieve [5]:
nD2
sa.h - nr2 - -
(3)
here RH and DH are radius and diameter of the sieve hole respectively, mm.
If we put (3) to the (2), so, formula (2) is seen by following form:
F0 = Nn.h , (4)
When we did the experimental research on corn sheller machine, it was seen that, 4.5-5 per cent grain had been coming out together with pith and husk through pith and husk outlet of the corn sheller machine. Then, we made a decision that it is optimal solution to separate grain from pith and husk by the even surface sieve which is formed rectangle. So, the surface of the sieve is equal to following formula:
F = Bs • Ls, (5)
here BS is width of the sieve and LS is length of the sieve.
According to above written (4) and (5) equalities, formula (1) is seen by following manner:
N -I nDk 1 2
B • L
(6)
So, the coefficient of the useful area of circle form holed sieve is determined according to formula (6). Now, if we imagine the sieve hole of the corn sheller is equal side triangle (figure 2).
B
a / h
Figure 2. The scheme of the equal side triangle formed hole sieve
According to figure 2, SAH in the (2) is equal to following formula for equal side triangle form holed sieve [5]:
a 2S
SH.A =
4
(7)
h = -
l < h =-
(8)
(9)
here a — length of the one side the equal side triangle, h in the figure 2 is equal to the following formula:
2 '
However, h has to be equal to the following formula for easy going down of the grain through sieve hole:
a%/3 2 '
here lg — length of the grain, mm. a in the formula (7) may be determined by the bellow formula:
h , N cosa=-, (10)
a
If we determine a by the formula (10), it is seen by following manner:
h , ,
a =-, (11)
cosa
So, formula (7) is seen by next formula: h
sh.a =
cosa
■S
4
If we put (12) to the (2), so, next formula is appeared:
h Y S
F = N
n .h
cosa
4
(12)
(13)
According to above written (5) and (13) formulas, the coefficient of the useful area of equal side triangle hole sieve is determined by the following manner:
N„
cosa
■S
B ■ L
(14)
Then, if we imagine the sieve hole of the corn sheller is rhomb form (figure 3).
Figure 3. The scheme of the rhomb formed hole sieve
So, according to figure 3, SAH in the (2) is equal to following formula for rhomb form holed sieve [5]:
SA H = a2sina,
(15)
According to scheme of the figure 3, di and d2 must be that d1 > lg and d2 > lg respectively. So, a in (15) can be determined by the following formula:
di
cosa = —, (16)
a
a can be found by the above written (16) and it is equal to following formula:
di
a = (17)
cosa
Thus, if we put (17) to the (15), it is appeared by following manner:
(a Y
sa.h =
di
2
cosa
■ sma,
(18)
Then, when we put (18) to the (2) next formula is appeared:
' d V
F = N„
cosa
■ sma,
(19)
According to above written (5) and (19) formulas, when the holes of the sieve are rhomb form, the coefficient of the useful area of sieve is determined by the following formula:
( d Y
N ■
n .h
2
cosa
■ sma
m = -
B ■ L
(20)
Next counting work is done by the square hole of the corn sheller sieve (figure 4).
So, according to figure 4, SA.H in the (2) is equal to following formula for square form holed sieve [5]:
SA.H = a2, (21)
here a is size one of the side of hole, mm. And it must be equal to that a > ¡s. So, if we put (21) to the (2), formula (2) is seen by following form:
F0 = Nn.h ■ a2, (22)
Figure 4. The scheme of the square form holed sieve
According to above written (5) and (22) formulas, when the holes of the sieve are square form the coefficient of the useful area of sieve is determined by the following formula:
N„
B ■ L
(23)
Then, if we imagine the sieve hole of the corn sheller is rectangle form (figure 5).
Figure 5. The scheme of the rectangle form holed sieve So, according to figure 5, SAH in the (2) is equal to following formula for rectangle form holed sieve [5]:
sa.h = ab, (24)
here a and b are width and length of the hole of sieve respectively, according to size of grain a and b must be a > lg and b > l . So, formula (2) is written by following manner:
F = nn.h -(ab), (25)
According to formulas (5) and (25), if the hole of the sieve is rectangle form the coefficient of the useful area of sieve is determined by the following formula:
N„
■(a-b)
B ■ L
(26)
In conclusion, it is seen that by above written formulas (6), (14), (20), (23) and (26) the coefficient of the useful area of corn sheller sieve depends on numbers ofholes, their size, total area of the holes, also sieve's width and length. When values were counted according to formulas (6), (14), (20), (23) and (26) Nnh = 273 pieces; DH = 15 mm; n = 3.14; BS = 350 mm; LS =460 mm; h = 15 mm; d1 = 15 mm; a = 15 mm; b = 8.7 mm. ^ was determined 0.59, 0.20, 0.12, 0.38 and 0.22 respectively.
So, it is required that, the coefficient must be > 0.5 for being high work efficiency of the corn sheller sieve. For preparing the sieve of the corn sheller machine we must pay attention to above written requirement and the holes of the corn sheller sieve must be made in optimal distance. According to theoretical research, circle form hole is optimal for corn sheller machine's sieve to separate the grain from husk and pith.
References:
Astonakulov K. D., Fozilov G. G., Kodirov B. X., Ochildiyev O.Sh., Khatamov B. A. Patent No. FAP 00776. Corn sheller for shelling the pod corn//Official information paper. - 2012. - No. 12.
2
h
4
2. Fozilov G. G. Determination description of the mixture which is coming through pith and husk outlet of the corn sheller machine//per-spective of development private business of agriculture: Devoted for 20 years of independence Republic scientific-applied conference's articles collection. -Andijan: - 2011. - P. 260-262.
3. Astanakulov K. D., Fozilov G. G. and others. "Development of early harvesting technological process of the ear cereal plants and corn also creating the high effective new technical implements for crop harvesting as well redevelopment the existent implements" account of the scientific-research work. - Gulbakhor, 2010. - P. 76-77.
4. Fozilov G. determination the coefficient of the useful area of corn sheller sieve according to circle holes. Journal Agro ilm. - No. 1 (39), 2016. - P. 71-72.
5. Mathematics: collection of formulas. - Moscow, Astrel, 2013. - P. 51-56.
Shukurova Sevara Egamkulovna, Bakiev Masfarif Ruzmetovich Tashkent Institute of Irrigation and Melioration, Tashkent, Uzbekistan E-mail: [email protected]
Floodplain correction by varying build-up combined dikes
Abstract: In the article the relationships for determination of flow dynamic axes deflection, specific discharges in unobstructed flow section has been obtained and carrying capacity has been evaluated for varying build-up combined dike perforated section asymmetrically obstructing flow.
Keywords: dam, dam combination, deaf dam, dam-through variable construction, waterworks, tightness flow hydraulics, the degree of tightness, spreading.
In spite of the fact that the idea of combined dike construction has been known long ago [1], combined dikes has been built relatively recently in Amudarya river at Takhiatash water structure complex.
Floodplain correction project in Amudarya river at Karshi main canal water intake structure has been also executed with the use of combined dikes. They asymmetrically obstruct flow in order to direct flow into water intake point.
Operation of combined dikes with constant build-up perforated part has been discussed in works [2; 3; 4].
The main principles of varying build-up perforated spur dike construction and theoretical bases for their design has been reviewed in work [5] for the first time.
The scheme for asymmetrically obstructed flow by constant build-up combined dikes is illustrated in the picture.
Picture 1. Flow asymmetrical obstruction Specific discharge uniform plot reforms in section line I-I under dike action and in section 0-0 its shape looks like what is shown in the picture.
The discharge approaching the blank dike fully declines from the protected bank only when one part of the discharge approaching the perforated dike declines to unobstructed area of floodplain and the other part passes through perforated dike to tail-water on account of gradual decrease of build-up coefficient.
by varying build-up combined dams.
Obstruction dissymmetry provides more intense deflection of flow dynamic axes in the direction of shorter length dike.
The goal ofthe research within the scope ofthis article consists of:
- determining the dynamic axes deflection for left and right section of flow;
- determining the specifics discharges in unobstructed section. Considering the varying build-up along the length we accept
the velocity and specific discharge distribution behind beyond per-
