12.9 Grade High Tensile Black Button Head Hex Socket Allen Screws, M2 M2.5 M3 M4 M5 M6, Length 3–60mm

Introduction

This product series is high-strength 12.9 grade alloy steel button head internal hex socket allen bolts, finished with uniform black electroplating anti-corrosion coating. Covering six mainstream metric thread sizes including M2, M2.5, M3, M4, M5 and M6, the bolt shank lengths range from short 3mm thin-plate mounting up to long 60mm multi-layer component assembly to meet diverse fastening depth requirements.

The standard internal hex socket design enables convenient tightening and disassembly with matching allen keys, while the low-profile round button head reduces protruding height after installation to avoid collision and structural interference in narrow assembly spaces. Manufactured from high-tensile carbon alloy steel with precise rolling thread machining and smooth deburring surface treatment, these screws deliver outstanding toughness, impact resistance and long service life. Balancing superior mechanical load-bearing performance and cost efficiency, they serve as universal heavy-duty fastening hardware widely adopted for furniture assembly, industrial equipment fixture installation, automotive, marine and vehicle accessory fixing as well as various mechanical assembly projects.

Technical Specifications

Basic Parameters

Full Name: 12.9 High Tensile Black Button Head Hex Socket Allen Screw / Socket Cap Bolt
Strength Grade: 12.9 High Tensile Grade
Raw Material: High Strength Alloy Carbon Steel
Surface Treatment: Black Electroplating Anti-Rust Coating
Thread Size Options: M2, M2.5, M3, M4, M5, M6
Valid Shank Length Range (Thread length excluding button head): 3mm ~ 60mm
Drive Type: Internal Hexagon Socket (Allen Key Operated)
Head Shape: Smooth Round Button Head

Size Marking Rule

Size is marked as Thread Diameter × Shank Length (the length measurement does not include the thickness of the button head)

Product Features

12.9 Grade High Tensile Alloy Steel Base Material

Constructed from premium high-strength alloy carbon steel and standardized heat-treated to reach 12.9 high tensile strength grade, the screws possess excellent structural toughness and heavy load-bearing capacity. They are not easy to deform, stretch or fracture under large clamping torque and long-term vibration load, perfectly fitting heavy-duty industrial fastening scenarios that demand high mechanical stability.
Black Electroplating Anti-Corrosion & Anti-Rust Coating

Uniform electroplated black surface forms a dense protective barrier to block air and moisture contact, providing reliable rust resistance, acid and alkali corrosion resistance and abrasion resistance. The coating maintains stable surface finish in damp workshop, vehicle compartment and outdoor semi-exposed environments without peeling or oxidation discoloration.
Burr-Free Precision Machining & Smooth Surface

Every screw undergoes fine deburring and polishing procedures after thread rolling and head stamping, delivering fully smooth surface without sharp burrs that may scratch assembly plates or damage matching threaded holes. Standard uniform thread pitch ensures smooth screwing in and out without sliding teeth or jamming during installation.
Comprehensive Resistance to Impact, Wear & Corrosion

Integrated outstanding impact resistance, surface wear resistance and chemical corrosion resistance. The button head will not crack under impact collision, the thread surface resists wear from repeated disassembly, and the whole screw maintains stable performance under complex working conditions for greatly extended service life.
Complete Size Series for All Assembly Demands

Covers miniature tiny M2 screws for precision electronic equipment up to heavy load M6 bolts for large mechanical frame fixing; shank lengths from 3mm to 60mm fully match thin sheet assembly, medium equipment frame installation and thick multi-layer component stacking work, eliminating custom screw opening mold costs for most conventional fastening applications.
High Cost Performance with Stable Quality

Strict standardized production process guarantees consistent product quality across batches, combining high tensile mechanical performance and affordable unit price. Compared with imported high-strength fasteners, this series achieves equivalent fastening reliability with lower procurement cost for mass factory assembly and DIY modification projects.
Compact Low-Profile Button Head Design

The rounded low-height button head minimizes surface protrusion after tightening, effectively lowering risks of wire snagging, component collision and structural interference inside slim equipment housings, cabinets and tight mounting spaces.

Application Scenarios

Industrial Equipment & Machinery Assembly (Core Application)

Widely used for fixture locking, equipment frame assembly, automation machine component fastening and mold accessory fixing in industrial plants. The 12.9 high tensile strength can withstand long-term equipment operation vibration without loosening, and the corrosion-resistant black coating adapts to oily, humid factory workshop environments, avoiding rust failure of internal machine fasteners.

Furniture Decoration & Hardware Installation

Ideal fasteners for solid wood furniture, aluminum alloy cabinet frames, display shelf brackets and decorative hardware assembly. The smooth black button head delivers neat uniform visual effect for exposed installation positions, while sufficient clamping force firmly locks wooden and metal furniture panels without loose joint gaps after long-term use.

Automotive, Motorcycle & Marine Vehicle Fittings

Applied to car interior trim panels, motorcycle frame fairing fixing, engine auxiliary bracket assembly and boat marine equipment accessory mounting. Anti-rust coating resists humidity, salt mist and engine oil erosion in vehicle and marine environments, and high tensile strength meets vibration resistance requirements of moving transport equipment.

Precision Electronic & Instrument Equipment

Small-size M2/M2.5/M3 screws fit mini instrument housings, 3D printer frames, drone fuselage components and circuit board fixing brackets. Compact button head design fits narrow slim internal equipment space without interfering with internal wiring and electronic parts.

DIY Craft, Model & Household Hardware Refitting

Popular hardware for handmade metal models, robot assembly, home appliance maintenance and custom DIY equipment modification. Rich thread and length size options satisfy various light and medium load fixing demands for amateur creators and daily household repair work.

Engineering & Construction Auxiliary Fixtures

Used for temporary construction fixture fixing, aluminum profile frame assembly and mechanical test bench bracket locking. The impact and wear resistant structure withstands frequent disassembly and repeated installation during construction and testing cycles.

- Exact dimensions can also be viewed in the photo gallery.

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Note:

- Please allow minor errors due to manual measurement. Thank you for your comprehension.

- Monitors are not calibrated, the element color shown in the photos may differ slightly from the real object. Please take the real one as standard.

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