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SS304 oval head semi-tubular rivet
- Product description：SS304 oval head semi-tubular rivet
In scenarios such as electronic equipment, automotive interiors, and medical devices—where high requirements for lightweight fastening and corrosion resistance apply—rivets have become important connectors due to their characteristics of "no threads required and quick assembly". Among them, 304 crimped rivets (complying with the GB873 standard) and semi-hollow, hollow, and large flat round head rivets (with M3/M5 as common specifications) are based on the corrosion resistance of 304 stainless steel, combined with the lightweight advantages of different hollow structures. They adapt to diverse fastening needs ranging from precision electronics to heavy-duty equipment, and perform exceptionally well in vibrating and humid environments.
I. Product Definition: A Hollow Fastening System Under National Standard Specifications
304 crimped rivets GB873 and the series of hollow rivets all use 304 stainless steel (containing 18% chromium and 8% nickel) as the base material, with their core feature being "hollow structure + crimped fastening":
- 304 Crimped Rivets GB873: Produced in accordance with the GB873 national standard, they have a semi-hollow shank and mostly flat round or countersunk heads. A special tool is used to crimp and deform the end of the shank, forming a non-detachable fastening structure with the connected parts. They are suitable for connecting thin plates (thickness 0.5-3mm).
- Semi-Hollow Rivets: The middle part of the shank retains a solid area, with only the end being hollow. They balance strength and lightweight properties. Specifications M3/M5 are commonly used in electronic equipment casings and toy components. They require less crimping force during fastening, avoiding deformation of thin materials.
- Hollow Rivets: The shank is fully hollow (the hole diameter is approximately 1/3 of the shank diameter), and they are 20%-30% lighter than semi-hollow rivets. Suitable for weight-sensitive scenarios (such as drone frames and lightweight automotive components), the M5 specification can withstand medium loads.
- Large Flat Round Head Rivets: The head is a large-diameter flat round shape (e.g., the head diameter of an M3 rivet is approximately 6mm), with a contact area 50% larger than that of ordinary round heads. They are suitable for soft materials (such as plastic and leather) to avoid crushing the surface during fastening, and are commonly used in furniture and luggage accessories.
Their core difference from solid rivets lies in the "hollow structure": solid rivets are heavy and require large assembly force, while hollow rivets achieve lightweight by reducing material usage. At the same time, they lower the strength requirements for connected parts, making them particularly suitable for fastening thin or soft materials.
II. Standard Specifications: Core Technical Requirements of GB873
As the exclusive national standard for 304 crimped rivets, GB873 ensures product reliability in terms of dimensional accuracy, mechanical properties, and corrosion resistance:
- Dimensional Accuracy: Centered on the nominal diameter (with M3/M5 as common specifications), it specifies a shank length tolerance of ±0.1mm and a head thickness tolerance of ±0.05mm. The depth of the semi-hollow hole should be 1/2-2/3 of the shank length (e.g., for an M5×10mm rivet, the hollow hole depth is 5-6.7mm) to ensure uniform deformation during crimping; the straightness of the shank is ≤0.1mm/m to avoid deviation during assembly.
- Mechanical Properties: The 304 stainless steel base material has a tensile strength of ≥520MPa and a yield strength of ≥205MPa. After crimping, the shear strength of the rivet is ≥6kN for M3 and ≥15kN for M5, ensuring no detachment in vibrating scenarios; the connection strength between the head and the shank must pass a "pull-off test"—the head should not fall off when a load of 1.5 times the rated load is applied.
- Corrosion Resistance: 304 stainless steel inherently has corrosion-resistant properties. GB873 additionally requires no red rust after a 48-hour salt spray test, making it suitable for humid environments (such as bathroom appliances and outdoor equipment); some high-end products undergo passivation treatment to further improve salt spray resistance to 72 hours, meeting the requirements of medical devices and marine equipment.
III. Structural Advantages: Dual Breakthroughs in Lightweight and Adaptability
The structural design of the series of rivets focuses on "lightweight" and "multi-scenario adaptability", with three particularly prominent highlights:
First, the balanced corrosion resistance and strength of 304 material: Compared with ordinary carbon steel rivets, 304 stainless steel does not rust in humid, acidic, or alkaline environments, extending its service life by 3-5 times; at the same time, it has good ductility and is not easy to crack during crimping, making it suitable for the precise assembly of precision electronics (e.g., M3 rivets used for connecting mobile phone middle frames).
Second, the lightweight advantage of hollow structures: Semi-hollow rivets are 15% lighter than solid rivets of the same specification, and hollow rivets are 30% lighter. In automotive interiors (such as door panel buckles) and drone components, they can reduce the overall weight and improve product performance; moreover, the hollow structure reduces material usage and lowers production costs.
Third, the protective feature of large flat round heads: The large-diameter flat round head increases the contact area. When M3 large flat round head rivets are used for plastic toy panels, they can avoid crushing the plastic surface; the edges of the head are smooth and burr-free, which also prevents scratching clothes or skin when used in luggage and furniture, improving usage safety.
IV. Application Scenarios: Precise Adaptation of M3/M5 Specifications
As core specifications of the series of rivets, M3 and M5 cover multiple fields with their dimensional advantages:
- Electronics and Precision Equipment: M3 semi-hollow rivets are used for connecting headphone casings and router panels. Their lightweight design does not increase the weight of the equipment, and the 304 material prevents internal circuits from rusting due to moisture; GB873 crimped rivets are suitable for printer toner cartridges and copier components, and can resist vibration during equipment operation after crimping and fastening.
- Automotive and Transportation Field: M5 hollow rivets are used for fixing automotive seat buckles and interior panels, and their lightweight feature reduces the weight of the vehicle body; M5 large flat round head rivets are used for bus handrails and subway interiors. The large contact area ensures stable connection while avoiding scratching passengers.
- Home Furnishing and Medical Device Field: M3 large flat round head rivets are used for wooden furniture connectors and luggage hardware to protect the surfaces of wood and leather; M5 304 rivets are used for wheelchair accessories and medical bed rails. Their corrosion-resistant properties meet the humid disinfection environment of hospitals, ensuring usage safety.
V. Usage Precautions
Three points should be noted during use:
- Select the shank length according to the thickness of the connected parts, ensuring that the remaining shank length after crimping is 1.2-1.5 times the shank diameter (e.g., for an M5 rivet connecting a 2mm thick plate, select a shank length of 5-6mm).
- Use a special crimping tool to avoid uneven deformation of the shank caused by manual tapping, which may affect fastening strength.
- In humid environments, prioritize 304 rivets complying with the GB873 standard to ensure corrosion resistance and avoid connection failure due to rust.
As a "corrosion-resistant pioneer" in lightweight fastening, 304 crimped rivets GB873 and the series of hollow rivets (M3/M5) solve the fastening problems of thin materials, soft materials, and humid environments with the reliability of 304 material, the lightweight of hollow structures, and the adaptability of multiple specifications. They have become ideal connectors in the electronic, automotive, and home furnishing fields.