Causes of bucket tooth breakage (material defects, overload, improper installation), solutions for pin fall-off or bolt loosening

Material defects are a key factor in premature bucket tooth fracture. High-quality bucket teeth require high-strength, wear-resistant steel with strictly controlled carbon and manganese content. A manganese content below 1.2% can reduce the material's wear resistance by over 30%, leading to wear and cracking of the tooth surfaces when loading hard materials such as sand and gravel. A quenching temperature deviation exceeding 50°C during heat treatment can lead to uneven internal structure and stress concentration points, which can easily cause fracture during subsequent operation. Yuezhong uses Q355ND wear-resistant steel in production, strictly controls its composition using spectrum analyzers, and uses computer-controlled temperature-controlled quenching furnaces to ensure heat treatment accuracy, thus mitigating the risk of material defects at the source.

Overloading is a common cause of bucket tooth fracture. Bucket teeth for loaders and excavators are designed to withstand specific loads. For example, the rated load on a 20-ton loader's bucket teeth is approximately 120 kN. Forcibly loading hard rock or frozen soil exceeding 1.5 times the bucket capacity can cause stress on the teeth far exceeding the material's yield strength (approximately 345 MPa), leading to plastic deformation at the tooth root and subsequent fracture after repeated operation. Construction site surveys show that approximately 40% of bucket tooth fractures are related to overloading. For example, a project using a 16-ton excavator to load 25 tons of granite to meet deadlines resulted in tooth fracture after just three days.

Improper installation can exacerbate uneven loads on the bucket teeth, leading to fracture. Proper installation requires a gap of no more than 0.5mm between the tooth and the adapter, and precise securing with dowel pins. Excessive gaps can cause the tooth to wobble during operation, subjecting the tooth root to repeated impact loads. Without dowel pins, bolts alone can subject the bolts to additional shear forces, shifting the tooth's load point and increasing the risk of tooth breakage at the root-adapter connection. Some users omit dowel pin installation for convenience, increasing the probability of tooth breakage by 60%.

To address the issue of pin fallout, improvements are needed in both installation techniques and component selection. During installation, clean the pin and pinhole of any oil or impurities to ensure the mating surfaces are clean, then apply lithium-based grease to reduce wear. After inserting the pin, secure it with a cotter pin through the circular hole at the end and bend it, or use a retaining ring to prevent movement during vibration. Additionally, select pins with anti-slip grooves, which have a 40% higher surface friction coefficient than standard pins, reducing the risk of fallout. Yuezhong's matching pins are machined from 40Cr alloy steel and phosphate-treated for enhanced anti-slip and wear resistance.

Treating bolt loosening requires a combination of anti-loosening technology and routine maintenance. When installing bolts, adhere to the "cross-tightening" principle, and the torque must meet equipment standards. For example, bucket tooth mounting bolts typically require a torque of 80-100 N·m. Insufficient torque can easily lead to loosening, while excessive torque can cause the bolts to stretch and deform. Alternatively, double nuts can be used to prevent loosening, while applying thread lockers (such as Loctite 243) can effectively prevent loosening caused by vibration. During routine maintenance, it is recommended to check bolt torque every 50 hours of operation and tighten promptly if any looseness is detected. This can reduce failures caused by bolt loosening by 70%.

Problems such as broken bucket teeth, pin fall-off, and loose bolts can be avoided through rational selection, standardized operation, and regular maintenance. As a professional manufacturer, Yuezhong not only provides bucket teeth and supporting components that meet international standards, but also offers on-site installation guidance and maintenance training to help reduce the risk of equipment failure. If you encounter problems using bucket teeth or require customized bucket teeth for different working conditions, please contact Yuezhong. We will provide professional technical support to your project.