Flat Head Bolts Carbon Steel Furniture Grade ISO 9001 Certified Custom Non-Standard M6-M12 Zinc Plated

Descripción

What are Flat Head Bolts?

Flat head bolts (common reference standards: DIN 7991, ISO 10642, ASME B18.5) feature a 90° countersunk head design that sits flush with the material surface. Unlike pan head or round head bolts, which protrude above the surface, flat head bolts eliminate interference points, allow components to slide freely, and create smooth, professional finishes where clearance or aesthetics matter.

Material

• Carbon Steel: Property classes 4.8 (400 MPa tensile), 8.8 (800 MPa tensile), 10.9 (1040 MPa tensile), and 12.9 (1220 MPa tensile) [verify] deliver increasing load capacity for structural applications.

• Stainless Steel: A2-70 (70,000 psi tensile, equivalent to 304 grade) offers general corrosion resistance; A4-80 (80,000 psi tensile, equivalent to 316 grade) provides enhanced resistance to chlorides and marine environments.

• Alloy Steel: SCM435 chromium-molybdenum alloy [verify] meets high-strength requirements for automotive and heavy equipment assemblies after heat treatment.

Surface Finishes

• Zinc Plated: Delivers 48+ hours [verify] salt spray protection. First choice for general industrial indoor applications balancing cost and corrosion resistance.

• Black Oxide: Provides cosmetic dark finish with minimal corrosion protection. Spec for tooling, automotive interiors, and light-duty applications where oil film supplements protection.

• Dacromet: Offers zinc-aluminum coating for high-corrosion environments. Resists 500+ hours [verify] salt spray without hydrogen embrittlement risk.

• Plain (Uncoated): Use with thread-locking compounds or sealants. Specify for post-plating assemblies or controlled indoor environments.

Specification Parameters

• Diameter: M3 through M24 metric; #4 through 1-inch imperial

• Length: 6mm to 200mm metric; 1/4-inch through 8-inch imperial

• Head Angle: 90° countersunk standard (critical for flush mounting verification)

• Drive Types: Hex socket (most common), Torx, slotted, Phillips, external hex

Vertical Application Scenarios

Precision Sheet Metal Enclosures: Flat head bolts join thin-gauge panels without protruding heads. The 90° angle seats perfectly in countersunk holes, allowing adjacent components to mount flush against the surface.

Automated Equipment Rail Systems: Linear guide rails require low-profile fastening to prevent carriage interference. Flat head bolts mount below the rail surface, maintaining uninterrupted travel paths for bearings and sliders.

Outdoor Electrical Cabinets: Utility enclosures pair flat head bolts with sealing washers. The flush head allows gaskets to seal continuously around the fastener, preventing water ingress while maintaining a professional appearance.

Customer Case

Situation: A conveyor system manufacturer reported recurring product jams at transfer points. Protruding hex head bolts securing guide rails caught product packages, causing line stoppages and damaged goods.

Task: Engineering required flush-mounted fasteners that maintained full clamping strength while eliminating all surface protrusions. Assembly access from one side remained mandatory for field maintenance.

Action: Supplied M8 x 25mm flat head bolts, property class 8.8, zinc-plated, with hex socket drive. The 90° countersunk head seated flush with rail surfaces. Socket drive enabled one-sided installation with standard hex keys.

Result: The manufacturer reported complete elimination of jam-related downtime. Maintenance crews continued using existing tools, and the flush surface allowed packages to transfer smoothly across all conveyor junctions.