Home » Socket Flanged Button Screws (ISO 7380-2) - High Tensile Steel (10.9) - Black

Socket Flanged Button Screws (ISO 7380-2) - High Tensile Steel (10.9) - Black

FULLERKREG ISO 7380-2 Grade 10.9 Black Flanged Button Head Socket Cap Screws

FULLERKREG ISO 7380-2 Grade 10.9 Black Flanged Button Head Socket Cap Screws are high-strength fasteners featuring a low-profile dome-shaped button head with an integrated flange and a hexagon socket drive. Manufactured from 10B21 boron-alloyed steel with a black oxide surface treatment, these screws deliver Grade 10.9 tensile strength (min. 1,040 MPa) with the added benefit of a built-in flange that distributes clamping load over a significantly larger bearing area — eliminating the need for a separate washer in most applications. The flange also provides a positive seating surface that prevents the screw from pulling through thin or soft materials.

Product Specifications

  • Standard: ISO 7380-2 (2022)
  • Strength Grade: 10.9 (heat treated)
  • Material: 10B21 boron-alloyed steel
  • Tensile Strength: Min. 1,040 MPa
  • Yield Strength: Min. 940 MPa
  • Hardness: HRC 32–39
  • Head Type: Flanged button head (low-profile dome with integrated flange)
  • Surface Treatment: Black oxide (blackening)
  • Thread Type: Metric coarse, full thread
  • Thread Tolerance: 6g
  • Drive Type: Hexagon socket (Allen key / hex key)
  • Sizes Available: M4 – M16

ISO 7380-2 vs ISO 7380-1 — Flanged vs Plain Button Head

The key difference between ISO 7380-2 and ISO 7380-1 is the integrated flange. Understanding this helps you select the right fastener:

Property ISO 7380-2 Flanged (This Page) ISO 7380-1 Plain Button Head
Head profile Low dome + integrated flange Low dome only
Bearing surface area Significantly larger (flange) Standard button head
Washer required? No — flange acts as integrated washer Sometimes yes
Pull-through resistance Superior Standard
Load distribution Excellent on thin/soft materials Good
Assembly efficiency Faster — one fewer component Standard
Overall head height Slightly taller (flange adds height) Lower profile
Best for Thin panels, soft materials, high pull-through risk General low-profile applications

The Flange Advantage — Why Choose ISO 7380-2?

The integrated flange in ISO 7380-2 provides several engineering advantages over plain button head screws:

  • Eliminates separate washer — reduces part count, assembly time, and risk of washer misalignment or loss
  • Superior pull-through resistance — the flange distributes clamping load over a much larger area, preventing pull-through in thin sheet metal, plastic, and composite materials
  • Positive seating — the flat flange underside provides a consistent, repeatable seating surface for accurate torque control
  • Vibration resistance — larger bearing area reduces the risk of loosening under vibration
  • Clean appearance — integrated flange looks more finished than a separate washer assembly

Material — 10B21 Boron Steel Chemical Composition (%)

FULLERKREG ISO 7380-2 Grade 10.9 flanged button head screws are manufactured from 10B21 boron-alloyed steel. The addition of boron (B) significantly improves hardenability, enabling Grade 10.9 mechanical properties with a leaner alloy composition. All values are maximum unless a range is indicated.

Grade C Si (max) Mn P (max) S (max) B
10B21 0.18–0.23 ≤0.30 0.80–1.10 ≤0.030 ≤0.030 0.0005–0.003

Mechanical Properties — Grade 10.9 (ISO 898-1)

Property Requirement Unit
Tensile Strength (Rm) Min. 1,040 MPa
Yield Strength / Proof Load Stress (Rp0.2) Min. 940 MPa
Core Hardness 32–39 HRC
Surface Hardness (max) ≤44 HRC
Elongation after fracture (A) Min. 9 %
Reduction of area (Z) Min. 48 %
Impact energy (KV) at room temp. Min. 37 J
Thread Tolerance Class 6g —
Surface Treatment Black oxide (blackening) —

Key Features

  • Integrated flange — built-in washer function eliminates need for separate washer, reducing part count and assembly time
  • Grade 10.9 high strength — 1,040 MPa tensile strength for demanding structural and mechanical joints
  • Superior pull-through resistance — large flange bearing area prevents pull-through in thin sheet metal, plastic, and composite materials
  • Low-profile button head — smooth dome design with clean aesthetic appearance
  • Black oxide finish — professional matte black appearance with minimal dimensional impact
  • 10B21 boron steel — excellent hardenability and consistent mechanical properties through heat treatment
  • ISO 7380-2 (2022) standard — latest revision compliance
  • ISO/TS16949 quality management — hardness test, tensile test, and PPAP report available on request

Applications

FULLERKREG ISO 7380-2 Grade 10.9 black flanged button head socket cap screws are widely used in:

  • Thin sheet metal assemblies where pull-through resistance is critical
  • Plastic and composite material fastening (large bearing area prevents crushing)
  • Automotive body panels and interior trim components
  • Robotics and automation equipment frames
  • Electronics enclosures and control panels
  • Bicycle frames, motorcycle components, and sporting equipment
  • Industrial machinery and equipment where washer elimination improves assembly efficiency
  • Any application requiring Grade 10.9 button head screws with integrated washer function

Dimensional Specifications — ISO 7380-2 (Unit: mm)

Key dimensions per ISO 7380-2 (2022). The flange diameter (dc) is the critical additional dimension vs. ISO 7380-1.

Thread (d) Pitch (p) Head Dia. dk Max. Head Dia. dk Min. Flange Dia. dc Max. Flange Dia. dc Min. Head Height k Max. Head Height k Min. Key Size s Key Depth t Min.
M4 0.7 7.60 7.36 9.40 9.00 2.20 1.80 2.5 1.05
M5 0.8 9.50 9.22 11.80 11.40 2.75 2.25 3.0 1.35
M6 1.0 10.50 10.22 13.60 13.20 3.30 2.70 4.0 1.60
M8 1.25 14.00 13.57 17.90 17.50 4.40 3.60 5.0 2.20
M10 1.5 17.50 17.05 22.30 21.80 5.50 4.50 6.0 2.75
M12 1.75 21.00 20.48 26.70 26.20 6.60 5.40 8.0 3.30
M16 2.0 28.00 27.48 35.70 35.20 8.80 7.20 10.0 4.40

Frequently Asked Questions

Q: What is the difference between ISO 7380-1 and ISO 7380-2?
ISO 7380-1 is the plain button head socket cap screw with no flange. ISO 7380-2 adds an integrated flange under the button head, which significantly increases the bearing surface area. The flange acts as a built-in washer, eliminating the need for a separate washer in most applications and providing superior pull-through resistance.

Q: Do I still need a washer with ISO 7380-2 flanged button head screws?
In most applications, no. The integrated flange provides sufficient bearing area to replace a standard flat washer. However, for very soft materials or applications with specific sealing requirements, an additional washer may still be beneficial.

Q: Can Grade 10.9 flanged button head screws handle the same torque as Grade 10.9 socket cap screws?
No. Due to the shallower socket depth in the button head design, the maximum recommended tightening torque is lower than for standard socket cap screws (DIN 912) of the same grade. Always use ISO 7380-2 specific torque values.

Q: What is the flange diameter for each size?
Please refer to the dimensional specifications table above. The flange diameter (dc) ranges from 9.0 mm for M4 to 35.2 mm minimum for M16.

Q: Can I get material certificates and test reports?
Yes. PPAP reports, material certificates, hardness test reports, and tensile test reports are available upon request for all FULLERKREG products.

Packaging & Availability

  • Standard sizes M4 – M16 available in stock
  • Bulk carton packaging; small box and custom packaging available
  • Material certificates and test reports available on request
  • PPAP report available on request
  • Custom lengths accepted for large orders

Download Specification

Quality Assurance

All FULLERKREG ISO 7380-2 Grade 10.9 black flanged button head socket cap screws are manufactured under strict quality control procedures including:

  • Rockwell hardness test (HRC 32–39)
  • Tensile strength test (min. 1,040 MPa)
  • Dimensional inspection per ISO 7380-2 (2022), including flange diameter verification
  • Chemical composition analysis (10B21, B content verified)
  • Salt spray corrosion test
  • PPAP documentation available upon request

For wholesale pricing, bulk orders, or technical inquiries, please contact our sales team.

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