- ZHUHAI JIALI HARDWARE CO.,LTD.
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Cup head hexagon three combination screw
- Product description：The material of hexagon socket combination screw can be divided into iron and stainless steel. Iron is made with different iron screws and wires. In general, the wire of hexagon screw is 10101018, 10B
Cup head hexagon three combination screw
Material: stainless steel 304316, grade 8.8 high strength and grade 12.9 high strength
It can also support non-standard customization.
In the field of precision fasteners, non-knurled cup-head hexagon socket combo screws have become a common fastening solution in electronic equipment, precision instruments, automotive components and other fields, thanks to their unique appearance of "cup head (cylindrical head) without knurling", the convenient operation of hexagon socket, and the integrated structure of "screw + spring washer + flat washer". One of their core characteristics lies in the flexible material selection, which is mainly divided into two categories: ferrous and stainless steel. Among them, the ferrous type, with the advantage of strength improvement through heat treatment, is widely used in scenarios requiring high fastening force. Its wire selection and processing technology directly determine the product performance and service life.
From the perspective of material classification, the two materials of non-knurled cup-head hexagon socket combo screws are suitable for different scenarios. The stainless steel type inherits the weather resistance and corrosion resistance advantages of stainless steel fasteners, making it applicable to harsh environments such as humidity, acid and alkali. For example, in the internal connection of bathroom equipment and outdoor precision instruments, it can resist rust without additional plating. After installation, it has a neat appearance, and the non-knurled cup head can fit better with the equipment surface, enhancing the overall delicacy. On the other hand, the ferrous type features "customizable strength" as its core highlight. By selecting different types of ferrous screw wires and matching them with subsequent heat treatment processes, it can meet diverse needs from ordinary loads to high-strength loads. For instance, in the fixing of components around automotive engines and machine tool fixtures, high-strength ferrous combo screws can provide stable fastening force. Moreover, compared with stainless steel types, they have more cost advantages, making them a cost-effective choice for mass production scenarios.
For ferrous non-knurled cup-head hexagon socket combo screws, wire selection is the "foundation" of performance. Common types of ferrous screw wires in the industry include 1010, 1018, 10B21, etc. The differences in chemical composition and mechanical properties of different types determine their applicable product grades and application scenarios. The 1010 wire is low-carbon steel with low carbon content, featuring soft material, good toughness and low processing difficulty. It is suitable for manufacturing ordinary-grade combo screws with low strength requirements, such as the fixing of plastic brackets inside electronic equipment. Since it does not need to bear excessive loads, the ductility of 1010 wire can prevent the screw from breaking due to improper force during installation. The 1018 wire is medium-carbon steel with a slightly higher carbon content than 1010. It has moderate strength and hardness, and after simple processing, it can meet the fastening needs of daily mechanical components. For example, in the fixing of end covers of small motors, it can provide sufficient connecting force without damaging the connected components due to excessively hard material.
The 10B21 wire is the core raw material for manufacturing Grade 8.8 high-strength non-knurled cup-head hexagon socket combo screws. As low-carbon steel containing boron, the hardenability of 10B21 wire is significantly improved after adding boron. After heat treatment, it can form a uniform martensite structure, which significantly enhances the tensile strength and yield strength of the screw, fully meeting the mechanical standards of Grade 8.8 fasteners. In key connection parts such as automotive chassis brackets and heavy mechanical equipment, Grade 8.8 ferrous combo screws need to bear large vibrations and loads. The high-strength characteristic of 10B21 wire can ensure that the screw will not deform, slip or have other problems after long-term use, making it the "standard" wire for high-strength scenarios.
The processing technology of ferrous non-knurled cup-head hexagon socket combo screws, especially the subsequent treatment links, is crucial to ensuring product quality. Among them, the two major steps of "heat treatment" and "hydrogen relief plating" are directly related to the screw performance and the service life of the spring washer. After completing the cup-head shaping, hexagon socket grooving, and assembly of spring washer and flat washer, the ferrous screw needs to undergo a heat treatment process: the screw is heated to a specific temperature (usually 850-900℃), kept at that temperature for a period of time, then rapidly cooled (quenching), and finally subjected to low-temperature tempering. Through this process, the hardness and strength of the screw are improved. After heat treatment, the hardness of the screw made of 10B21 wire can reach HRC22-30, and the tensile strength exceeds 800MPa, meeting the Grade 8.8 standard.
"Hydrogen relief plating" is the key process to prevent the spring washer from breaking. During the plating process of ferrous combo screws, hydrogen ions in the electrolyte may penetrate into the spring washer, forming a "hydrogen embrittlement" phenomenon — when the spring washer bears external force or vibration, the accumulation of hydrogen atoms inside increases its brittleness, making it prone to breaking. Therefore, after heat treatment, the screw needs to be placed in a special hydrogen relief furnace and kept at a temperature of 190-230℃ for 2-4 hours to promote the escape of hydrogen atoms inside the spring washer and reduce the risk of hydrogen embrittlement. Subsequently, plating processes such as galvanizing and nickel plating are carried out, which not only improve the corrosion resistance of the screw but also ensure that the spring washer maintains elasticity during long-term use, avoiding fastening failure caused by breakage.
In practical applications, the finely processed ferrous non-knurled cup-head hexagon socket combo screws cover various scenarios with stable performance. In the automotive industry, Grade 8.8 combo screws made of 10B21 material are used for connecting gearbox housings and valve bodies, and their high strength after heat treatment can resist the impact and vibration during gearbox operation. In the field of electronic equipment, ordinary-grade combo screws made of 1010 material are used for fixing internal plastic parts of printers and scanners. The non-knurled cup head will not scratch the plastic surface, and the processing cost is low, making it suitable for bulk purchase.
From material selection to process details, every step of the non-knurled cup-head hexagon socket combo screw is centered around "meeting needs". The ferrous type balances strength and safety through precise wire selection and fine heat treatment and hydrogen relief processes; the stainless steel type excels in weather resistance. Together, they form a diversified application system of this fastener, providing reliable support for precision fastening needs in various fields.