Coal mining picks are one of the main consumables in coal mining machines. With the advancement of intelligent, high-yield, and efficient coal mining, the proportion of hard coal seams and gangue-containing composite coal seams being mined continues to increase. Coal picks are subjected to high-frequency impacts, abrasive wear, alternating loads, and high-temperature friction. Frequent replacement not only interrupts continuous production but also significantly increases consumable costs and underground operational safety risks, directly restricting mining efficiency and increasing the cost per ton of coal produced.
The main failure modes of coal mining bits are as follows:
1. Abrasive wear: The tooth tip becomes blunt, the alloy head wears down, and the cutting ability is lost.
2. Impact fracture: Impact from gangue causes the carbide head to chip and crack; alternating loads generate fatigue cracks in the tooth body, leading to tooth shank fracture.
3. Weld failure: Insufficient brazing strength causes the entire alloy head to detach; impact cracking leads to the entire carbide head detaching.
4. Thermal fatigue failure: Cutting friction generates instantaneous high temperatures, and spray cooling causes repeated thermal expansion and contraction, resulting in a network of microcracks on the tooth head, accelerating the wear and fracture process.
To address the aforementioned issues, Luoyang Golden Egret has focused its research on upgrading materials, innovating processes, and improving structures to enhance the overall performance of cutting teeth in terms of wear resistance, impact resistance, and fatigue resistance.
Luoyang Golden Egret balances hardness and toughness by adjusting the tungsten-cobalt ratio in its alloy teeth. For soft coal seams and hard coal seams with intercalation of gangue, they use gradient cobalt-containing cemented carbides and WC powders with different grain sizes to prepare cemented carbides, improving strength while maintaining hardness. RS1 high-strength alloy steel is selected as the base material for the tooth body and forged. Simultaneously, a composite heat treatment process is employed to enhance the fatigue resistance of the tooth body and significantly reduce fatigue fracture.
Luoyang Golden Egret Coal Minig Picks Application Case
In a coal mine in Jincheng, Shanxi Province, Luoyang Golden Egret and Manufacturer K conducted comparative tests on U95 coal mining cutting picks. After on-site comparison underground, the consumption ratios of the two specifications of cutting picks from Luoyang Golden Egret and Manufacturer K were 1:8 and 1:1.8, respectively. Overall, the consumption of our company's cutting picks was lower, and the customer recognized the effectiveness of our products.
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Mining Face Operating Information |
Total length 124 frames (approximately 210 meters), mining height approximately 3.5 meters. Frames 70-84 consist of gangue and large interbedded rocks (blue sandstone, high hardness and strong abrasiveness), the remainder being coal seams. |
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Equipment Brand and Drum Type |
Tiandi 1650 Coal Mining Machine Diameter: 2.24 meters, single drum can hold 54 cutting teeth, 24 cutting teeth are installed on the inner ring of the drum. |
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Installation Method |
10 cutting teeth are installed on the inner ring of the head drum, the remaining 14 are installed on the K manufacturer's drum. Comparison only of cutting tooth consumption on the inner ring of the drum. |
Working Conditions and Application Scenarios of Underground Rock Strata
| Cutting Section | Consumption Volume | Inner Drum Ring King Bit Proportion | Inner Drum Ring K1 Proportion | Consumption Ratio Comparison: King Bit vs K1 | |
|---|---|---|---|---|---|
| Head drum cuts from frame 93 to frame 63. The fault strata after blasting are relatively loose. Coal haulage runs back to frame 84 at the tail, then machine halts for pick inspection
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K1: 12 pcs | King Bit: 1 pc | 10/24 | 14/24 | 1/8 |
| Cutting Section | Consumption Volume | Inner Drum Ring King Bit Proportion | Inner Drum Ring K2 Proportion | Consumption Ratio Comparison: King Bit vs K2 | |
|---|---|---|---|---|---|
| ① Head drum cuts from frame 93 to frame 63. The fault strata after blasting are relatively loose. Coal haulage runs back to frame 84 at the tail, then machine halts for pick inspection
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K2: 15 pcs | King Bit: 5 pcs | 9/24 | 15/24 | 1/1.8 |
| Cutting Section | Consumption Volume | Inner Drum Ring King Bit Proportion | Inner Drum Ring K Proportion | Consumption Ratio Comparison: King Bit vs K | |
|---|---|---|---|---|---|
| Head drum cuts from frame 84 to frame 77. The fault strata after blasting are relatively solid. Machine halts for pick inspection
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