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0STUDY OF A CYLINDRICAL SURFACE DURING DIAMOND GRINDING
KHAMROEV KHAMZA KHAMIDOVICH
senior tutor
Bukhara Engineering and Technology Institute, Bukhara, Uzbekistan
SAVRIYEV YULDOSH SAFAROVICH
docent
Bukhara Engineering and Technology Institute, Bukhara, Uzbekistan
SHODIYEV ZIYADULLO OCHILOVICH
docent
Bukhara Engineering and Technology Institute, Bukhara, Uzbekistan
Abstract: The article discusses the properties of metals and alloys that characterize the ability to resist external forces, the ability of metals and alloys to resist impact forces depending on the application of force (whether static, dynamic or variable). Determining the hardness of a metal is the most important study to assess the ability of a material to withstand deformation. The main quality indicators - hardness, durability, and long-term performance - depend on various other properties. In modern technology, information about its dependence on the nature of the impact (stretching, bending, compression or twisting). The Brinell method is used to determine the hardness of metals. The WP 300 universal instrument was used in Brinell's tests.
Key words: metal, impact force, resistance, elongation, plastic properties, mechanical properties, metal hardness, Brinell method, mechanical press, hardened steel ball, sample, diamond triad, strength
Introduction. The properties that characterize the ability of metals and alloys to resist the action of external forces are called their mechanical properties. The ability of metals and alloys to resist the forces acting depends, firstly, on the insertion of the force (whether the force is static, dynamic or variable), and secondly, on its nature of action (whether it is stretching, bending, compressing or twisting) [1,2,3].
Testing the hardness of metals. The ability of a metal to resist the immersion of an object harder than it on its surface is called the hardness of that metal.
Knowledge of the hardness of metals is necessary for these metal scrapers, as metal scraping is largely dependent on its hardness; shearing modes are also determined by the hardness of the metal. The technique has several methods for determining the hardness of metals, among which the Brinel and Rockwell methods are common.
Experimental part. Brinel method. This method is used only when determining the hardness of non-polished metals. Depending on the consistency of the metal to be determined and its thickness, a polished steel ball with a diameter of 2.5; 5 and 10 mm is gradually immersed in the testing sample with a strength of 187 kg, 750 kg and 3000 kg in a given time, as a result of which a trace of a steel ball falls on the Figure 13 describes the scheme of the brinel mechanical press and the method for determining the hardness of metals in it. In the experiment, we will use a universal device WP 300 [3].
If we mark the face of the trace of the Sphere falling on the testing metal with the letter F, we can express the hardness of the metal on the Brinel by the formula:
P
H В = — kg /mm2 F
Draw 1. Brinel press scheme. When testing the hardness of metals, to be able to calculate it every time, a maxsuc table was compiled (Table 1). According to the diameter (d) of the spherical trace found in this table, the hardness of the metal on the Brinel scale is determined [5].
Tab
Diameter of the Hardness on Brinel, Diameter of the ball Hardness on Brinel,
sphere face, on in the HB kg/mm2 track, in mm in kg/mm2
account of mm count account HB
D D
3,8 255 4,5 179
3,9 241 4,6 170
4,0 229 4,7 163
4,1 217 4,8 156
4,2 207 4,9 149
4,3 196 5,0 143
4,4 187 5,1 137
5,2 131
5,3 126
5,4 116
5,5 111
Carbon steels have a known bond between hardness and strength, this bond is expressed by the following formula:
Ob = 0,33 +0,36 HB
Draw 2. Universal device for WP 300 materials test.
The abbreviation HBS is added to the hardness value on polished steel balls or the hardness value on balls made from the abbreviation HBW Carborundum. In Brinell hardness surface tests, the
ball pressure (load) of a certain diameter D is placed vertically on the detail being processed, which is checked using the F control pressure (load), with consistent increase, and is performed with a specific test pressure (load) over a certain period of time. This process performs the pressing of the sphere, after which the diameter D of the resulting spherical segment is measured after the test pressure (load) is removed [3].
The sample should not move during this process.
The degree of hardness in Brinell is calculated based on the test pressure (load) F and the AV impact area of the spherical segment.
The hardness value on HB Brinell is f Test pressure (load) - N.at Av impact area-mm2 The coefficient of 0.102 is used for historical reasons, taking into account the change
(conversion)from kp/mm2 to kn/mm2.
Draw 3. WP 300 universal rigoracu (10 kN Force effect)
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Citing Time
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Draw 4. WP 300 Brinell test program Draw 5. WP 300 Brinell test program
(results obtained)
In the experiment wp 300 universal rigoracura 10 kN Force effect.(Figure 4). We enter the results obtained in the WP 300 Brinell test program. The material's durability to eat depends, among other things, on its hardness. The harder the Material,the stronger its edible resistance. The stiffness belongs to mechanical resistance, with which the body enters against the attack of another object. Accordingly, in the process of normative testing of the hardness surface, the surface of the sample is under the vertical pressure of the solid object being tested. In a sample, a three-axis voltage occurs under the object where the pressure is being exerted. Due to this, the constant (constant) level of pressure can be achieved even in very hard and brittle (fracture) materials without material damage. This differentiates hardness-to-surface testing from stretching-to-surface testing, in this testing
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process, only a one-axis voltage state is created in the sample, which makes plastic deformation impossible in solid materials. One of the dominant aspects of hardness-surface testing is that, in contrast to stretching-surface testing, material descriptions can be collected without sample distortions unless small crushed areas in the sample object are taken into account. The disadvantages are that in hardness-to-surface tests, only one hardness description can be determined, not from the hardness itself, but depending on the event of conducting the Test (test). Due to this, the test process must always be indicated along with the hardness value.
In Tests on Brinell, a balloon made of Carborundum or a polished steel balloon is used as a test sample according to ISO 6506. For the WP 300 materials test, a polished steel ball is used in the universal device. The ISO 6506 standard recommends the use of a balloon made of Carborundum, due to which the determination of hardness on Brinell using a universal device for the WP 300 materials test is carried out on the basis of the ISO 6506 standard.
Conclusions. We compare the results obtained with the amounts that we bring to the references. In order not to count it every time when testing the hardness of metals, a maxsuc table is compiled (Table 1). The results obtained by analogy have an almost birz pointer. In conclusion, by determining the mechanical properties (hardness) of materials, it allows students to establish their theoretical knowledge in the experiment. At the same time, students shape their knowledge and skills [3].
REFERENCES:
1. Materials science and engineering. An Introduction. William D.Callister, Jr. David G. Rethwisch. 346 b.
2. Fundamentals of modern manufacturing. Marerials, processes and systems. Fourth editions. Mikell P. Groover. 156 b.
3. N.S.Bibutov, Khasanov S.M, Khojiev A.X, Roziev Sh.R. "Material resistance". experimental work on the subject. Bukhara,"Durdona" 2017, page 324
4. https://hozir.org/2--laboratoriya-ishi-metallarning-qattiqligini-brinell-usuli-b.html
5. http://www.fayllar.org/materialshunoslik-mavzu-metall-va-qotishmalarning-xossalarini.html?page=2
6. 197368216.pdf (core.ac.uk)
