In rock drilling engineering, the shank adapter plays a crucial role as a connecting component. The selection of materials and processing technology are directly related to the performance and service life of the shank adapter. This article will discuss the materials and processes of shank adapters to help readers better understand and apply relevant knowledge.
What is a shank adapter?
The shank adapter is a key component connecting the rock drilling tools and rock drill. When working, it directly bears high-frequency impact and strong torsion of the rock drill, transmits the impact work of the rock drill piston movement from the end of the shank adapter to the drill rod and the rock drill bit, so it needs to have good strength, toughness, and abrasion resistance. To ensure the quality of shank adapters, the correct selection of materials and proper manufacturing processes are crucial.
Selection of shank adapter material
Shank adapters are often used in large and medium-diameter threaded connections and supporting drilling tools for drilling rigs. Because the shank adapters are frequently in a high-frequency, high-power shock cycle stress state. The selection principle of the shank steel grade must be tough and wear-resistant and have good rigidity and toughness. Its mechanical properties require good hardenability.
Shank adapters generally use high-quality alloy steel as raw materials. Alloy steel is the addition of alloying elements, such as manganese, molybdenum, and vanadium, to carbon steel to improve the strength, toughness, wear resistance, and corrosion resistance of materials. 35SiMnMoV is a commonly used alloy steel with good mechanical properties and wear resistance, suitable for shank adapters manufacturing.
The geometric structure and parameters of the shank adapter
The shape geometric structure design and parameter selection of the shank adapter directly affect the performance of the rock drill and supporting drilling tools and the rock drilling efficiency of the entire drilling process. Therefore, the design principle of the shank adapter, on the one hand, is to meet the high-frequency, high-power impact, and rotational stress requirements of rock drills. In addition, to slow down the stress concentration tendency formed by the change of geometric dimensions of various parts on the shank adapter body, appropriate transition arc treatment should be carried out in all grooves, grooves, steps and other sections and stress buffer transition areas, and water (gas) The method and size of a reasonable choice to ensure the drilling life of the shank adapter.
As one of the supporting drilling tools for rock drilling, the shank adapter is relied on to connect other drilling tools during the drilling process. For this reason, its thread structure shape has a definite internal relationship with the connection thread structure and precision of the supporting drilling tools. It should meet the requirements of convenient loading and unloading, labor saving, reliable connection, good wear resistance, and high service life during use. As a result, the geometric design and selection of dimensional parameters of shank adapters are affected by many factors. It has a great relationship with the model and specification of the rock drill but also has a lot to do with the thread structure and dimensional accuracy of the matching coupling sleeve and threaded drill rod.
The manufacturing process of shank adapters
In the manufacturing process of shank adapters, their geometric dimensions, precision, and internal quality are the key factors affecting the service life of shank adapters, and advanced manufacturing technology and equipment are the prerequisites for ensuring the quality of shank adapters. In the manufacture of shank adapters, despite the different levels of process technology and equipment, the process flow of domestic and foreign manufacturing plants is similar.
The more typical process flow is as follows:
Raw material inspection – cutting to length – straightening – forging billet – soft annealing – machining – heat treatment – surface cleaning – grinding outer circle – anticorrosion – packaging – storage.
The heat treatment process of shank adapters
The heat treatment process of the shank adapters has a crucial influence on the performance and quality of the shank adapters. The typical shank adapters’ heat treatment processes include normalizing, quenching, tempering, carburizing, etc. Quenching and tempering are the most commonly used heat treatment processes.
Quenching is to heat the shank adapters to a specific temperature and then cool them quickly to increase the hardness and strength of the material. Tempering is reheating the quenched shank adapters to a specific temperature and then cooling it slowly to reduce the material’s brittleness and improve its toughness. Carburizing is the process of infiltrating carbon into the surface of the shank adapter to improve its hardness and wear resistance.
During heat treatment, attention needs to be paid to the control of temperature, time, and atmosphere to ensure the performance and quality of the shank adapters to the best level. In addition, to prevent cracks and deformation during heat treatment, pretreatment, and heat preservation treatment are required before heat treatment.
Common defects and prevention measures of shank adapters
During the manufacturing process of shank adapters, some deficiencies may appear, such as low surface hardness, insufficient carburized layer depth, and surface decarburization. These defects will affect the performance and quality of the shank adapters, so corresponding preventive measures need to be taken.
To prevent low surface hardness, the quenching temperature or cooling rate can be increased appropriately in the heat treatment process. To prevent insufficient depth of the carburized layer, the carbon potential and carburizing time can be increased appropriately in the carburizing process. To prevent surface decarburization, control the atmosphere and temperature in the heat treatment process to avoid oxidation.
Considerations for shank adapters in practical application
In practical applications, the performance and service life of the shank adapter are affected by many factors, such as the working environment and usage methods. Therefore, you need to pay attention to the following points when using the shank adapter:
1. Choose the suitable material for the shank adapter and process it based on the working environment to ensure optimal performance and extended service life.
2. During use, the operator should avoid excessive force or impact to avoid damage to the shank adapter.
3. Regularly inspect and maintain the shank adapter, discover and deal with potential problems in time, and extend the service life of the shank adapter.
Conclusion
Understanding the material and manufacturing process of the shank adapter is crucial to making a high-quality shank adapter. Correct material selection and manufacturing process can ensure that the shank adapter has sufficient strength, toughness, and wear resistance to meet the requirements of the rock drill. In practical applications, different models of shank adapter materials and processes are available according to specific needs and conditions.
