Flat Head Closed Round Body Knurled Blind Rivet Nuts

Size Can also be According to the Customer's requirement. APlease check the detailed specification sheet PDF and CAD. See more product details, PDF 91-92 Page.

Designed with a closed end and a sizeable flanged head with a cylindrical groove and O-ring seal mounted underneath, Juxin Fastener’s cold-formed Juxin fasteners blind rivet nuts in steel and stainless steel offer a worry-free, watertight fastening solution in many critical applications.

A setting tool performs an axial crimping action during rivet nut installation. The O-ring seal slides into the groove and is compressed between the flanged head and the plate or profile where the rivet nut is installed. The hex-shaped shank prevents spin out, resisting a torque-to-turn force of at least 30Nm in M8.

After setting, the unique head design ensures metal-to-metal contact on either side of the O-ring that firmly remains in the conically shaped recess, resulting in optimal seal compression. This guarantees a well-functioning seal, ideally positioned away from possible burrs or sharp hole edges and protected against UV light.

The under-head seal protects against fluids, moisture, oil, or dirt ingress, even under up to 10 bar pressure. The Juxin fasteners' design is IP 68, guaranteed under Juxin fasteners test conditions, and available in thread sizes M5 to M8. The standard O-ring seal material is NBR (Buna-N). Still, other O-ring materials (Viton, EPDM, silicone, etc.) can be offered when a specific pressure, temperature resistance, or chemical compatibility is required. 

Originally designed to prevent leaks in a boot hinge assembly in a premium car, the watertight JuXin Fasteners are a trusted solution in many other challenging applications, too. demanding applications

As application requirements became increasingly complicated, other watertight rivet nut solutions must be conceived. Therefore, Juxin Fasteners developed the flat-head blind rivet nut series, involving a non-reactive peripheral seal made of flexible, organic-based material applied to the under-head bearing surface of a flat-head Tubtara rivet nut.

The polyurethane seal compound is resistant to many automotive oils, antifreeze, and transmission fluids and has a sealing capacity exceeding 150 bar. The material offers a temperature resistance from -40 °C to 100°C for continuous usage (150°C peak temp) and is gap-filling, forming a robust seal between mating surfaces. Slight variations in seal thickness may influence head height and grip range, but a correctly installed flat head blind rivet nut ensures an IP 67 waterproof assembly.

This seal can be applied under the flat head of stocked standard parts in all materials and shank shapes, offering OEM customers very short delivery times. It is the preferred solution for numerous applications, such as roof rack assemblies, battery packs, or enclosure covers.

New Juxin fastener developments focus on their outstanding sealing properties rather than on fastening. The latest designs feature options like male or female threads or hose connections, offering zero-risk assembly solutions in HVAC and fluid control applications.

The thread area is enclosed, which prevents leakage past the threads from either side of your application. These rivet nuts have a ribbed body to hold them in place when tightening a screw. The body and flange are zinc yellow-chromate plated steel for corrosion resistance. Install in a drilled hole using a rivet nut tool. The tool collapses the nut, creating a backside flange that holds the nut to the material. Length is measured from under the flange. Installed length is the maximum length of the barrel when installed.

Closed-end inserts offer the advantage of offering a 100% watertight connection, meaning the thread cannot be damaged by water or dirt.

In particular, these rivet nuts are safe for electrical circuits since no fluids can get in.

Fast Facts:

Blind hole, one-sided installation capability.

Provide load-bearing threads in sheet materials.

Offers a water- and air-sealed connection.

It is suitable for use in electrical circuits and in any applications (containers, tanks, airco systems) where a water-sealed connection is needed.

Available in stock in steel. Other materials are available on demand.

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Corrosion resistance: Zinc-nickel alloys have extremely high corrosion resistance, more than 3 times higher than pure zinc layers. At the same thickness, zinc-nickel alloy layers have 4-8 times the corrosion resistance of pure zinc coatings. This excellent corrosion resistance enables zinc-nickel alloy coatings to provide effective cathodic protection and significantly extend service life.

Wear resistance: Zinc-nickel alloy coatings are harder than pure zinc and therefore have better wear resistance. This characteristic makes zinc-nickel alloys excellent in applications where high wear resistance is required.

Low hydrogen embrittlement: The hydrogen embrittlement rate of zinc-nickel alloy coatings is only 1.5%, which is much lower than the embrittlement rate of electroplated pure zinc (typically over 40%). This characteristic is very important to avoid the degradation of material properties caused by hydrogen embrittlement, especially in areas with high demands on material strength and toughness.

Good solderability and machinability: Zinc-nickel alloys have good solderability and machinability, comparable to electroplated pure zinc layers. This means that zinc-nickel alloys can be processed through existing electroplated pure zinc processes without the addition of special equipment, while maintaining excellent corrosion resistance.

Excellent thermal stability: Zinc-nickel alloy coatings have excellent thermal stability and are able to maintain good corrosion resistance over a temperature range of -60 to 250°C, even after radical cooling and heat treatment.

Good bonding and passivation: There is sufficient bonding between the zinc-nickel alloy coating and the substrate to ensure that the coating exerts its high corrosion resistance. In addition, after passivation treatment, the corrosion resistance of zinc-nickel alloy can be greatly improved, and the quality of passivation film has a significant effect on the corrosion resistance.

In summary, zinc-nickel alloys are widely used in the automotive industry, energy field and other demanding industries due to their excellent corrosion resistance, wear resistance, low hydrogen embrittlement, good weldability and processability, and excellent thermal stability.

High-Sealing Components in New Energy Vehicles (NEVs)

In new energy vehicles, components requiring the highest sealing standards are concentrated in the “three-electric system”—battery pack, electric drive (motor), and electronic control units (ECUs). These core systems are directly linked to vehicle safety, reliability, and lifespan. Their sealing designs typically achieve IP67 or higher, with some high-end models reaching IP68.

1. High-Sealing Requirements in Battery Packs

The battery pack is the most critical component in NEVs. Operating voltages often exceed 200V, and the internal chemistry is highly reactive. Water ingress can cause short circuits, leakage, or even thermal runaway, making sealing performance paramount.

Protection Level:

Standard NEV battery packs: IP67 (waterproof up to 1 meter for 30 minutes)

High-end models (e.g., Zeekr, premium EVs): IP68, supporting longer and deeper immersion tests

Sealing Design Features:

Multi-layer protection including top/bottom gaskets (compression rate 30–60%)

Weld seam sealing with adhesives

Connector sealing with O-rings or gaskets

Waterproof blind rivet nuts with raised flange for mechanical fastening

Verification Standards:

In addition to standard water-intrusion tests, some manufacturers conduct 48-hour continuous immersion and post-impact waterproofing testing to ensure long-term safety under vibration, thermal cycling, and extreme operating conditions.

2. Electric Drive System (Motor + Electronic Control Unit)

The electric motor and ECU operate at high speeds, under substantial electromagnetic interference, and at elevated temperatures, imposing strict requirements on sealing materials and assembly design.

Motor Housing:

Prevents coolant from entering the stator winding

Standard solutions: stainless steel dual-lip oil seals, conductive silicone O-rings

Protection level: IP67 or higher

Electronic Control Unit (VCU/DC-DC, etc.):

Contains precision electronics that require dust-proof, moisture-proof, and condensation-resistant protection

Typical solutions: potting compounds, fully sealed housings

Protection level: IP67

Testing Methods:

Some manufacturers use vacuum-pressure leak testing on complex assemblies, such as motor housings and cooling lines, to ensure high sensitivity for sealing verification.

3. High-Voltage Connection Systems

High-voltage wiring, charging ports, and connectors, though small in size, can represent potential pathways for water ingress.

Charging Ports:

Must support outdoor use in the rain

Typically designed to IP67 waterproof standards

Some high-end ports feature integrated waterproof caps

High-Voltage Wiring Harnesses:

Sealed with liquid silicone rubber (LSR) or other high-performance materials

Ensures temperature resistance and electrochemical stability

Connector Mounting Holes:

Usually located on the upper section of the battery pack enclosure to minimize water exposure

Protected with dual-layer sealing (gaskets + adhesive sealant)

Summary:

In NEVs, the highest sealing requirements are concentrated in battery packs, electric motors, ECUs, and high-voltage systems. Using advanced sealing technologies—including IP67/IP68-rated components, multi-layer gaskets, blind rivet nuts, and potting solutions—ensures safety, reliability, and long-term durability even under vibration, thermal cycles, and harsh environmental conditions.

This makes high-sealing fasteners and components indispensable in modern EV design and production.

The inner packaging is a plastic bag, and the outer packaging is a carton. Then the tray. Carton size: 29*19*19.5CM and 23.5*17.5*8, CM and pallet size: 215*100*90CM, or as your request