Release time：2020-01-16 18:44 Browse：
1. Standard Compliance
These stainless - steel hex socket bolts strictly adhere to GB standards. The GB standard, such as GB/T 70.1 - 2008 for hexagon socket head cap screws, precisely defines the dimensional accuracy, mechanical properties, and other technical requirements. This compliance ensures that the bolts are interchangeable and reliable in various industrial applications. For instance, the diameter, thread pitch, and head dimensions are all specified to a high degree of precision, making them suitable for use in assemblies where tight tolerances are crucial.
2. Material Specifications
Manufactured from high - quality stainless steel, common grades include 304 and 316. Grade 304 stainless steel contains approximately 18 - 20% chromium and 8 - 10.5% nickel. The chromium forms a passive oxide layer on the surface of the bolt, which significantly enhances its corrosion resistance in general - purpose environments. This makes it suitable for indoor applications, such as in the assembly of furniture, electronics, and general machinery. Grade 316 stainless steel, on the other hand, has an additional 2 - 3% molybdenum. The molybdenum improves the material's resistance to pitting and crevice corrosion, especially in harsh environments. It is highly recommended for applications in the marine industry, chemical processing plants, and food and beverage industries, where exposure to saltwater, chemicals, or corrosive substances is common.
3. Design Features
Cylindrical Cup Head Design: The bolts feature a cylindrical cup head, which offers several advantages. The low - profile design of the cup head reduces protrusion in assemblies, minimizing the risk of snagging or interference with other components. The smooth cylindrical surface also provides an aesthetically pleasing appearance. The internal hexagon socket, which can be driven by Allen keys, allows for high - torque transmission. This enables precise tightening of the bolts, ensuring a secure and reliable connection. For example, in high - vibration machinery, the ability to apply high torque without cam - out is essential to prevent loosening of the bolts over time.
Threading: The bolts are available with metric threads, both coarse and fine pitch, in accordance with GB/T 196. Coarse - pitch threads are suitable for applications where quick assembly and disassembly are required, as they can be tightened and loosened more rapidly. Fine - pitch threads, on the other hand, offer better resistance to vibration and are often used in applications where a more precise and secure connection is needed, such as in precision machinery or aerospace components. The threads are carefully machined to ensure accurate engagement with nuts and other threaded components, reducing the risk of cross - threading and improving the overall performance of the connection.
4. Dimensional Range
The bolts are available in a wide range of sizes. The diameter typically ranges from M3 to M30, and the lengths can vary from 10 to 300 mm. This extensive dimensional range allows for their use in diverse applications. Smaller - diameter bolts, such as M3 and M4, are often used in electronics and small - scale machinery, where space is limited. Larger - diameter bolts, like M20 and M30, are suitable for heavy - duty applications in construction, industrial machinery, and infrastructure projects. The availability of different lengths also ensures that the bolts can be used in assemblies with varying thicknesses of materials. For example, in a multi - layer structure, a longer bolt may be required to pass through all the layers and provide a secure connection.
5. Surface Finish
Standard Passivation: As a standard, the stainless - steel bolts are passivated, following GB/T 15519. Passivation involves treating the surface of the bolt with a chemical solution, usually nitric acid - based. This process removes any iron - rich contaminants from the surface and enriches the chromium content in the passive oxide layer. The result is an enhanced corrosion - resistant surface. Passivation is especially important for protecting the bolts in environments with moderate humidity and mild corrosive agents.
Optional Finishes: In addition to passivation, there are several optional finishes available. Polishing can be done to achieve a smooth, shiny surface. This not only improves the appearance of the bolts but also reduces the surface roughness, which can be beneficial in applications where dirt and debris accumulation need to be minimized, such as in food - processing equipment. PTFE (polytetrafluoroethylene) coating can be applied to provide a low - friction surface. This is useful in applications where the bolts need to be tightened and loosened frequently, as it reduces the torque required for rotation and minimizes wear. Black oxide coating can be used for both aesthetic and anti - glare purposes. It gives the bolts a black, matte finish, which can be suitable for applications where a non - reflective surface is desired, such as in optical or lighting equipment.
6. Applications
Industrial Machinery: Stainless - steel hex socket bolts are extensively used in industrial machinery. They are used to assemble various components, such as motors, gearboxes, and conveyor systems. The high strength and corrosion resistance of the bolts ensure the long - term reliability of the machinery, even in harsh operating conditions. For example, in a factory where there is exposure to dust, moisture, and vibrations, the bolts need to maintain their integrity to prevent equipment failures.
Electronics: In the electronics industry, these bolts are used to secure components in electronic enclosures. The non - magnetic properties of stainless steel, especially in grades like 304, make them ideal for use in sensitive electronic devices, where magnetic interference can affect the performance of the equipment. They also provide a secure and durable connection for printed circuit boards, power supplies, and other electronic components.
Construction: In construction, the bolts are used in the assembly of structural components, such as in the construction of buildings, bridges, and towers. Their high strength and corrosion resistance are crucial for ensuring the safety and longevity of the structures. For example, in coastal areas where there is high humidity and salt - laden air, stainless - steel bolts are preferred over carbon - steel bolts to prevent rusting and degradation of the structure.
Automotive Sector: In the automotive industry, the bolts are used in the assembly of engines, chassis, and body components. They need to withstand high mechanical stresses, vibrations, and temperature variations. The corrosion - resistance of stainless steel is also important, as the bolts are often exposed to road salt, moisture, and other corrosive substances in the automotive environment.
7. Quality Control
Tensile Strength Testing: Tensile strength testing is carried out in accordance with GB/T 228.1. This involves subjecting the bolts to a gradually increasing tensile force until they break. The results are compared to the minimum requirements specified for the particular grade of stainless steel. For example, for a grade 304 stainless - steel bolt, the minimum tensile strength should meet a certain value, and if the tested bolt fails to reach this value, it is considered defective.
Thread Inspection: Thread inspection is done using GB/T 3934. Specialized thread gauges are used to check the pitch, diameter, and form of the threads. The gauges are designed to ensure that the threads are within the specified tolerances. If the threads are not accurate, it can lead to problems such as poor engagement with nuts, cross - threading, and reduced connection strength.
8. Advantages
High Torque Tolerance: The hexagon socket design allows for the application of high torque, enabling a secure and tight connection. This is crucial in applications where the connection needs to withstand high mechanical loads and vibrations.
Minimal Head Projection: The low - profile cylindrical cup head reduces the amount of protrusion in assemblies, which is beneficial in applications where space is limited or where a smooth surface is required to prevent interference with other components.
Compatibility with Automated Assembly Tools: The standardized design of the bolts makes them compatible with automated assembly tools, such as robotic screwdrivers and torque - controlled fastening systems. This improves the efficiency and accuracy of the assembly process, especially in high - volume production environments.
