Home » ISO 7380 Button Head Socket Cap Screw Grade 10.9 Black

ISO 7380 Button Head Socket Cap Screw Grade 10.9 Black

FULLERKREG ISO 7380-1 / GB70.2 Grade 10.9 Black Button Head Socket Cap Screws

FULLERKREG ISO 7380-1 / GB70.2 Grade 10.9 Black Button Head Socket Cap Screws are high-strength fasteners featuring a low-profile dome-shaped button head with 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) in a compact, aesthetically clean button head profile. They are the preferred choice for applications requiring both high clamping force and a low-profile, professional appearance — such as robotics, automotive, precision machinery, and structural assemblies where standard socket cap screws are too tall.

Product Specifications

  • Standards: ISO 7380-1 / GB 70.2
  • 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: Button head (low-profile dome)
  • Surface Treatment: Black oxide (blackening)
  • Thread Type: Metric coarse, full thread
  • Thread Tolerance: 6g
  • Drive Type: Hexagon socket (Allen key / hex key)
  • Sizes Available: M3 – M16

Grade 10.9 Button Head — Strength vs Profile Comparison

Understanding how Grade 10.9 button head screws compare to other common options helps you select the right fastener:

Property ISO 7380-1 Grade 10.9 (This Page) ISO 7380-1 A2-70 Stainless DIN 912 Grade 10.9
Head profile Low dome (button) Low dome (button) Tall cylinder
Tensile strength Min. 1,040 MPa Min. 700 MPa Min. 1,040 MPa
Material 10B21 boron steel SUS304 stainless Alloy steel
Surface Black oxide Passivated Black oxide / zinc
Corrosion resistance Moderate (indoor) Excellent Moderate
Max. tightening torque Medium (button head limit) Lower High
Best for High-strength + low profile Corrosion resistance + aesthetics High-torque structural joints

Material — 10B21 Boron Steel Chemical Composition (%)

FULLERKREG ISO 7380-1 Grade 10.9 button head screws are manufactured from 10B21 boron-alloyed steel. The addition of boron (B) significantly improves hardenability, enabling Grade 10.9 mechanical properties to be achieved 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

  • Grade 10.9 high strength — 1,040 MPa tensile strength, significantly stronger than Grade 8.8, in a compact button head profile
  • Low-profile button head — smooth dome design, approximately 50% lower than standard socket cap screws (DIN 912)
  • Wide bearing surface — larger head diameter distributes clamping load over a greater area vs. socket cap screws
  • 10B21 boron steel — excellent hardenability and consistent mechanical properties through heat treatment
  • Black oxide finish — professional matte black appearance with minimal dimensional impact on thread fit
  • ISO 7380-1 / GB 70.2 dual standard — suitable for both international and Chinese domestic supply chains
  • ISO/TS16949 quality management — hardness test, tensile test, salt spray test, and PPAP report available on request

Applications

FULLERKREG ISO 7380-1 Grade 10.9 black button head socket cap screws are widely used in high-strength, space-constrained applications:

  • Robotics and automation equipment (high strength + low profile)
  • Automotive structural components and chassis assemblies
  • Precision machinery and CNC equipment
  • Wind power and energy generation equipment
  • Electronics enclosures requiring high-strength fasteners with clean appearance
  • Bicycle frames, motorcycle components, and sporting equipment
  • Industrial fixtures and tooling
  • Any application requiring Grade 10.9 strength with a button head profile

Dimensional Specifications — ISO 7380-1 (Unit: mm)

Thread (d) Pitch (p) Head Dia. dk Max. Head Dia. dk Min. Head Height k Max. Head Height k Min. Key Size s Key Depth t Min. Body Dia. ds Max. Body Dia. ds Min.
M3 0.5 5.70 5.50 1.65 1.35 2.0 0.74 3.00 2.86
M4 0.7 7.60 7.36 2.20 1.80 2.5 1.05 4.00 3.82
M5 0.8 9.50 9.22 2.75 2.25 3.0 1.35 5.00 4.82
M6 1.0 10.50 10.22 3.30 2.70 4.0 1.60 6.00 5.82
M8 1.25 14.00 13.57 4.40 3.60 5.0 2.20 8.00 7.78
M10 1.5 17.50 17.05 5.50 4.50 6.0 2.75 10.00 9.78
M12 1.75 21.00 20.48 6.60 5.40 8.0 3.30 12.00 11.73
M16 2.0 28.00 27.48 8.80 7.20 10.0 4.40 16.00 15.73

Frequently Asked Questions

Q: What is the difference between ISO 7380-1 and ISO 7380-2?
ISO 7380-1 is the standard button head socket cap screw with a plain button head. ISO 7380-2 features a button head with a flange (wider bearing surface). This page covers ISO 7380-1 (no flange).

Q: Can Grade 10.9 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 refer to the torque specification for ISO 7380-1 specifically, not DIN 912 values.

Q: Why use Grade 10.9 instead of Grade 8.8 for button head screws?
Grade 10.9 provides 30% higher tensile strength (1,040 MPa vs. 800 MPa) and higher yield strength (940 MPa vs. 640 MPa). For applications with high clamping force requirements, vibration, or dynamic loads, Grade 10.9 is the correct choice.

Q: What is GB 70.2?
GB 70.2 is the Chinese national standard for button head socket cap screws, equivalent to ISO 7380-1. These screws comply with both standards and are interchangeable in most applications.

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

Packaging & Availability

  • Standard sizes M3 – M16 available in stock
  • Bulk carton packaging; small box and custom packaging available
  • Material certificates and test reports available on request
  • Custom lengths accepted for large orders

Download Specification

Quality Assurance

All FULLERKREG ISO 7380-1 Grade 10.9 black 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)
  • Salt spray corrosion test
  • Dimensional inspection per ISO 7380-1
  • Chemical composition analysis (10B21, B content verified)
  • PPAP documentation available upon request

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

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