Rotary drilling rigs need to choose the appropriate teeth according to the geology. The correct selection of the teeth can improve the working efficiency of the rotary drilling rig and reduce the construction cost. The commonly used teeth of the rotary drilling rig are as follows:
The carcass of the pick is generally a high-strength alloy steel, and the alloy head is a hard alloy.
Among the pick-cutting models in the drilling pile market, such as HQ3050-22,30-finger seat fitting diameter (mm), 50-maximum diameter of the carcass (mm), 22 refers to the maximum diameter (mm) of alloy parts.
At present, the diameters of the common cutting alloy heads on the market are 19, 22, and 25mm, and 22mm is the most widely used.
Advantages: the point of the tooth is in point contact with the formation, the contact area is small, and it can provide a large penetration force.
Disadvantages: When drilling in strata with low strength, the crushing efficiency is low; in strata with great strength, the picks are severely worn.
Stratigraphy: dense sandy gravel, hard frozen soil, hard rock, etc.
Bucket teeth are made of a relatively hard wear-resistant alloy. The types of bucket teeth currently used in the market are 25T, V19, and V20.
25T is a patented product of the United States Iceco, with a middle pin, which is less difficult to process and has a higher unit price;
V19 is also a US-based patented product, with side latches, which is difficult to process, has good installation stability, and has a high unit price. V20 is a domestic tooth, which is similar to V19 in installation and has a high cost performance. Common teeth.
Advantages: the contact between the tooth tip and the formation is a line contact, the contact area is large, and the drilling efficiency is high.
Disadvantages: The tooth strength is low, and it is easy to be damaged when the strength is strong.
Strata is recommended: soil layers other than dense sand and dense gravel.
The shovel tooth is an upgraded version of the bucket tooth and has high strength.
Advantages: The contact between the tooth tip and the ground is linear, and the contact area is large. High drilling efficiency.
Disadvantages: After the strength of the tooth back is strengthened, a certain drilling resistance will be caused when drilling, and the drilling efficiency of the soil layer is not as good as that of ordinary bucket teeth (V19, V20, 25T).
Strata is recommended for drilling: soft sand and very soft rock formations such as dense sand, dense pebble, strong weathered bedrock, moderately weathered mudstone, and moderately weathered muddy cemented sandstone (limestone).
4. Cone teeth
When the roller rotates with the rotary drilling rig, the teeth of the roller will rotate, and the rock will be broken by the impact load generated by the rotation.
Advantages: smooth drilling and less damage to equipment.
Disadvantages: The single tooth is expensive, and the excessively high pressure can easily damage the teeth.
Strata is recommended: extremely hard rock formations such as moderately weathered and slightly weathered granite, diorite, siliceous limestone, siliceous sandstone.