PERCUSSION ABRASIVE WEAR OF DROBILES ON WORKING DETAILS MADE FROM SOLID ALLOYS

ABSTRACT

This article describes the impact-abrasive wear of abrasive particles from a hard alloy under the action of a flow of particles during ore crushing, the angle of impact of abrasive particles, the initial size of abrasive particles, the initial size of abrasive particles, the initial concentration of abrasive particles, the moisture content of the crushed material, the number of abrasive particles dedicated to laws.

АННОТАЦИЯ

В данной статье описаны ударно-абразивный износ абразивных частиц из твердого сплава под действием потока частиц при дроблении руды, угол удара абразивных частиц, исходный размер абразивных частиц, исходный размер абразивных частиц, исходная концентрация абразивных частиц, влажность измельчаемого материала, количество абразивных частиц, посвященных законам.

Keywords: а crusher, а finger, the working capacity, Energy dispersive X-ray spectroscopy, scratched areas, abrasive particle.

Ключевые слова: дробилка, палец, работоспособность, энергодисперсионная рентгеновская спектроскопия, поцарапанные области, абразивная частица.

Introduction

One of the main factors influencing the efficient, uninterrupted and high-quality operation of ore crushers used in mining and metallurgical enterprises is the impact resistance of the parts directly involved in the crushing of the ore to impact abrasive wear [1-2]. Therefore, in most cases, the working parts of the crushers (knives, fingers, hammers, etc.) are made of WC-Co based hard alloy. The main reason for this is that the wear resistance of hard alloys in one WC-Co group is higher than the wear resistance of other types of materials [3-4]. However, it is still difficult to conclude that WC, Ti-based hard alloys fully meet the modern requirements for the wear resistance and cost of materials used by mining companies. Because one of the main problems in solving this problem is that the improvement of the operational properties of WC, Ti based hard alloys often leads to an increase in the cost of their production [5-6].

In our opinion, one of the most optimal ways to improve the operational properties of WC, Ti-based hard alloys, especially impact abrasive abrasion without increasing the cost of production, is to study their abrasive abrasion mechanism and adapt the physical and mechanical properties of hard alloys to operating conditions. In this paper the results of a study on the mechanism of impact abrasive crushing that occurs in the working parts of ore crushers made of WC-Co based hard alloy is presented.

Object and method of the research

In order to study the mechanism of impact abrasive wear of tungsten carbide cobalt hard alloy,in the "Selective smelting unit" of the Central Mining Administration of JSC "Navoi Mining and Metallurgical Combine" found 94% WC A finger detail made of a hard alloy containing + 6% Co was selected. A picture of a finger grinding ore in a crusher for 110 hours is shown in Figure 1.

In order to study the mechanism of impact abrasive corrosion of tungsten carbide cobalt hard alloy, in the “Selective melting unit in the assembly”, the Central Mining Administration of JSC "Navoi Mining and Metallurgical Combine " made a finger detection of 94%WC+6%Co hard alloy of “CEMCO” and “BARMAK” crushers used in crushing ores containing rare metals. A picture of a finger grinding ore in a crusher for 110 hours is shown in Figure 1.

Figure 1. A finger that grinds ore in a crusher for 110 hours: A - Abrasive weared surfaces

The finger is 232 mm long and 38.1 mm in diameter, 6 pieces are placed between the rotor of the crusher and the lining plates, the working capacity of the crusher averages 220 t/h, while the total working resource of the fingers is 110 hours. During ore grinding, the average depth of the surface on one side of the finger that was eaten was 8 mm, while the mass of the finger before eating was 3.8 kg and the mass after eating was 2.09 kg. The abrasive absorption of the material was 2.36 t/g.

The chemical and granulometric composition of the ore crushed in the crusher is given in Tables 1 and 2.

Table 1.

«Gold smelting shop»chemical composition of ore fragments

Table 2.

 «Gold smelting shop»granulometric composition of the ore

To study the abrasive abrasion process that occurs in hard alloys, samples measuring 15x10x5 mm were cut from the abrasive surface of the finger using a diamond disk and the areas were photographed using SEM-EVO MA 10 (Zeiss, Germany) scanning electron microscope.

Results and discussions

Pictures 2, 3 and 4 show the magnification of x100 to x1000 times using SEM - EVO MA 10 (Zeiss, Germany) scanning electron microscope of different areas of the surface exposed to impact abrasive wear on the finger.

Figure 2. Macrostructure of the abrasive weared surface of a hard alloy, x100: a - scratched; b - solidified abrasive particle; s - stained areas

During the analysis of the structure of the surface subjected to abrasive wear, there are three categories of areas (Fig. 2, a, b, c) that differ from each other in terms of their origin on the surface: a - scratched areas; b - abrasive particle areas penetrated into the solid alloy base and s - black stained areas of unknown origin were identified.

An image of a particle piercing the surface of a hard alloy is shown in Figure 3.

Figure 3. Pictures of scratched area: a - scratched area of ​​different degrees; b - punctured abrasive particle; c - the abrasive particle adhering to the surface

Figure 4. Energy-dispersion X-ray spectroscopy of ore fragments sunk into the finger surface and area

At different magnifications of the abrasive weared surface of the finger (Fig. 3), the particle immersed in the body of the hard alloy and its mark left during immersion are clearly visible (b). It can also be seen that the surface of the particle is partially melted and a portion of it flows to the side and sticks to the material (c). An energy-dispersion X-ray spectroscopy was performed in the area to determine if the particle flowing from the particle belonged to it. The results are shown in Figure 4.

According to the results of the analysis, the particle and the adjacent part of it showed that the origin of the products between the cracks is the same. In addition, the image clearly shows cracks of different sizes and shapes on the surface around the particle (Figure 4). A structural analysis of the surface perpendicular to the eroded surface was performed to determine the origin of the pits around the submerged particles and how deep they were (Figure 5).

Structural analysis of the perpendicular surface to the impact abrasive weared surface showed that the scratches themselves and adjacent lines (Fig. 5, a) have a transverse dimension of 25 ... 50 μm, length 250 ... 350 μm, depth 200 ... 300 mkm were found to be cracks. In the areas of the cracks close to the eroded surface, the tungsten carbide grains were broken, and at the lower ends, the crack passed along the cobalt binder between the carbide particles. This indicates that the crack was caused by a large impact on the material.

Figure 5. A crack on the surface of the finger perpendicular to the bent surface

Conclusion

According to the results of the study, the mechanism of impact abrasive abrasion on the surface of the finger part of the crusher made of tungsten carbide cobalt hard alloy is a complex process and it consists of at least three stages occurring simultaneously. In the first stage, the surface of the hard alloy begins to crack on the surface under the influence of a series of blows by large pieces of ore; The second stage begins with the increase in the amount of cracks in the surface unit, in which the ore fragments begin to knock the amount of material in the micro-volume from the body of the solid alloy with their blows; in the third stage, the crushed ore particles continuously grind the surface of the hard alloy.

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