Din 6921

Flange Bolt
A specialized bolt featuring an integrated flange washer (flange collar) as its core design. Characterized by an expanded serrated or flat circular disc beneath the hex head, it eliminates the need for traditional bolt + separate washer assemblies, engineered to address three critical challenges

DESCRIPTION

PRODUCT Tags

Parameter	Specification & Range	Test Standard
Standards	DIN 6921 (Serrated) · ISO 4162 (Flat) · ANSI B18.2.1 (Hex Flange) · JIS B1189	ISO 898-1
Flange Type	Serrated · Flat · O-ring Groove	DIN 6921 Sec.4.2
Thread Specification	M6-M36 · UNC/UNF #4-1½" · Pitch: Standard/Fine (e.g. M12x1.25)	ISO 261/262
Flange Diameter (D)	1.7×d to 2.5×d (d=thread diameter) · e.g. M10: Φ17-25mm	DIN 6921 Table 1
Serration Angle	30° (DIN) · 45° (ANSI)	DIN 6921 Fig.1
Tooth Depth	0.4-0.8mm (flange diameter dependent)	ISO 16047
Material Grade	Carbon Steel: 8.8 (800MPa) · 10.9 (1040MPa) · Stainless: A2-70(700MPa)/A4-80(800MPa)	ISO 898-1/3506-1
Surface Treatment	Electro-Zinc	ASTM B633
Torque Value (Nm)	M10 Grade 10.9: Clamp Force 64kN · Torque 85Nm (lubricated)	VDI 2230
Operating Temp.	Carbon Steel: -50℃~+250℃ · Stainless: -200℃~+400℃	ASTM A193

Key Applications
Flange bolts (also known as frame bolts or flange head bolts) are characterized by an integral, circular flange (washer-like bearing surface) directly beneath the bolt head. This flange distributes clamping force over a wider area than a standard bolt head, reducing surface pressure, preventing pull-through in softer materials, and often eliminating the need for a separate washer. This makes them suitable for a wide range of applications:
Piping Systems & Pressure Vessels:
Flanged pipe connections (ASME B16.5, B16.47, etc.) for oil & gas, chemical processing, water treatment, power generation (steam, water lines).
Pressure vessel manways, nozzles, and cover plates.
Pump and valve connections.
HVAC systems (high-pressure ducting, chillers).
Automotive & Transportation:
Engine assemblies (cylinder heads, manifolds - though often studs/nuts, bolts are used).
Transmission and drivetrain components.
Suspension systems (bushings, brackets).
Chassis and frame assembly.
Exhaust system components (manifolds, flanges).
Wheel mounting (lug bolts often have a flange).
Machinery & Industrial Equipment:
Assembly of heavy machinery frames, housings, and guards.
Mounting motors, gearboxes, and pumps.
Securing covers, access panels, and inspection ports on equipment.
Material handling equipment (conveyors, cranes).

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din 6921

din 6921 8.8

DIN 6921 Hex Flange Bolt – High-Strength Fastening Solution

DIN 6921 bolts are hex flange bolts designed with an integrated flange under the head, providing a larger bearing surface to distribute load and eliminate the need for separate washers. Available in strength grade 8.8, these bolts offer excellent mechanical performance for demanding industrial and automotive applications.

DIN 6921 Hex Flange Bolt 8.8: Reliable High-Strength Bolts for Secure Assemblies

DIN 6921 Standard – Ensured Quality and Dimensions

Manufactured to meet DIN 6921 specifications, these hex flange bolts guarantee consistent size, thread, and flange dimensions for easy integration into assemblies and reliable performance.

Strength Grade 8.8 – High Tensile and Yield Strength

The 8.8 grade indicates a high-strength bolt made from medium carbon steel, quenched and tempered to provide excellent tensile and yield strength suitable for heavy-duty fastening.

Hex Flange Design – Load Distribution and Washer Elimination

The integrated flange under the bolt head increases the contact area with the surface, distributing clamping forces evenly and eliminating the need for additional washers, simplifying installation.

Versatile Applications in Automotive and Machinery

DIN 6921 8.8 bolts are commonly used in automotive assemblies, heavy machinery, construction, and structural applications where secure and durable fastening is critical.