The drill rod is a rock drilling tool that connects the drill bit and the shank adapter in the rock drilling system and transmits the driving force of the rock drill to the drill bit through the threaded connection to achieve the purpose of rock drilling. During the rock drilling process, it is necessary to withstand the cyclic stress of tension, compression, bending, and torsion imposed by high-frequency, high-impact rock drills under the action of wear and corrosive media. Its service life is not long due to the influence of the rock drilling environment and other factors. The failure forms of drill rods have normal and abnormal failures. The causes of different failure forms are different, but many failures are mostly caused by product quality or human operation. How to solve them and keep us away from the trouble?
Understand the types and materials of drill rods
First, it is fundamental to understand the type of drill rod we use (such as integral drill rod, tapered drill rod, or threaded extension rod) and its material. Drill rods of different materials and types suit different operating environments and geological conditions. Choosing the right drill rod can significantly improve durability and work efficiency.
Understand typical solutions to drill rod failures
1. For the fatigue from the outer surface caused by using a hammer on stuck steel or the nick or dent on the surface layer, we should use the drill rod wrench to twist the stuck steel to loosen.
2. Due to the fatigue originating from the outer surface caused by improper care and handling, the surface layer of steel will be compromised by a nick or dent. The solution to this problem is storing rods in a rod rack carefully when retracting drill rods. Do not drop rods.
3. The solution to the fatigue originating in the bore caused by corrosion or corrosion caused by brine and other corrosive flushing agents is to evaluate if proper storage practices are being followed and change outer components more frequently or neutralize the flushing agent.
4. Wandering or drifting holes generate failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is employing straight hole drilling devices or systems.
5. Worn threads or coupling sleeves. Migrating coupling sleeve (bridge worn out) generates failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is replacing worn components. Do not put a worn coupling sleeve on a new rod. Change out your coupling sleeves with new rods.
6. Bending due to overfeeding generates failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is monitoring feed force and tuning to rock conditions.
7. Bending due to misalignment generates failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is to utilize alignment tools to monitor hole orientation once the hole has been collared. Replace wear pads on feed.
8. Heavy rotational loads caused by drilling with a dull bit and increased reflected stress generates failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is resharpening bits when the wear flats appear 1/3 dull or discarding when carbide profile height is compromised.
9. Drilling in voids, seams or broken conditions generates failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is to adjust drilling pressures and tunes to rock conditions.
10. Continued percussion when drill steel jams in void or seam generate failure occurs where the coupling sleeve ends or above the thread radius. Typically, a solution to sudden failure is to use a drill with anti-jam features. Reduce feed and percussion pressure.
11. Too much play in coupling. Drill steels improperly joined in coupling sleeve as a result of a thread or bridge wear generate chip broken off end of drill steel solution of replacing worn components.
Strategies to prevent drill rod failure
Select high-quality drill rods
- Material selection: prioritize high-strength and high-wear-resistant alloy steel materials to ensure the drill rod maintains excellent performance under harsh working conditions.
- Brand reputation: choose well-known brands with good market reputations, which usually have strict control over product quality.
Reasonable selection and use
- Matching equipment: ensure that the drill rod matches the power, speed, and other parameters of the drill jumbo.
- Regular inspection: check whether there are cracks, severe wear, and other problems with the appearance of the drill rod before construction, and replace damaged parts in time.
- Proper installation: follow the operating procedures to ensure the drill rod is firmly installed, preventing loosening, increased vibration, and early failure.
Optimize the operating environment
- Geological survey: conduct geological surveys before construction to understand the hardness of the rock and the development of cracks and select appropriate drilling methods and drill rod materials.
- Control drilling parameters: adjust the impact force and speed of the drill jumbo according to geological conditions to avoid excessive impact and breakage of the drill rod.
- Keep clean: regularly clean up debris around the borehole to prevent stones and soil from entering the borehole and affecting the proper operation of the drill rod.
Maintenance
- Avoid overload: avoid long-time continuous operation, and reasonably arrange rest time to prevent the drill rod from deformation or breakage due to overheating.
- Storage environment: during non-operation, the drill rod should be stored in a dry, ventilated environment without corrosive gases to avoid moisture and rust.
Fault handling and emergency measures
Fault identification and diagnosis
- Observe the phenomenon: pay attention to abnormal phenomena, such as the sound and vibration of the drill rod during operation, and find the signs of fault in time.
- Analyze the cause: analyze the specific cause of the fault in combination with factors such as drill rod material, working environment, and usage.
Emergency treatment
- Stop inspection: if signs of drill rod failure are detected, the operator should stop the machine for inspection to prevent the failure from worsening.
- Temporary repair: for minor wear or deformation, temporary repairs can be made by welding and grinding to ensure construction continuity.
- Replace spare parts: if the fault is severe and cannot be repaired, we should replace the drill rod with a new one in time to ensure safe and efficient operation.
Improve operator skills
- Professional training: organize operators to participate in professional training on a regular basis to enhance their knowledge of drill rod performance, operation skills, and fault-handling ability.
- Experience sharing: operators are encouraged to exchange experiences, share successful cases and fault-handling experiences, and jointly improve the operation level.
Conclusion
The drill rod is subjected to repeated pressure load cycles, and fatigue failure is inevitable. Factors that affect the fatigue life of drill rods are the material and smelting process, surface quality and geometry of the rod, and manufacturing process and drilling conditions, and if the rod breaks due to fatigue caused by one of these factors, the damage is enormous. Therefore, a trustworthy drill rod supplier, regular maintenance, and correct operation are very important for drill rods. In addition, if you want to extend the service time of the drill rod, you still need to analyze the failure causes according to the specific use conditions. Only in this way can the problem be solved basically.
