The Zinc Plated Carbon Steel Self Tapping Screw (commonly known as a sheet metal screw, tapping screw, pan head self tapper, countersunk self tapper, or DIN 7981 / DIN 7982 / DIN 968 fastener) is a high-performance threaded fastener engineered to form its own mating internal threads as it is driven into pre-drilled pilot holes in metal sheets, plastics, wood, and aluminum extrusions. Fabricated from premium C1022A cold-heading wire rod and subjected to continuous case-hardening heat treatment, our self-tapping screws combine sharp thread crests with high torsional strength in strict compliance with global ISO standards.
Technical Specifications of Self Tapping Screws
We produce a complete line of self-tapping screws featuring various head geometries to match specific clamping and aesthetic requirements. Case hardening establishes a hard outer skin (≥ 450 HV) that cuts effortlessly through sheet steel while maintaining a ductile core (270–390 HV) to resist shearing under high driving torque.
| Head Style & Standard | Drive Recess | Surface Hardness | Core Hardness | Primary Application Feature |
|---|---|---|---|---|
| Pan Head (DIN 7981 / ISO 7049) | Phillips (PH) / Pozi | ≥ 450 HV0.3 | 270 – 390 HV0.3 | High Bearing Area for General Metal & Plastic Assembly |
| Countersunk Flat Head (DIN 7982 / ISO 7050) | Phillips (PH) / Pozi | ≥ 450 HV0.3 | 270 – 390 HV0.3 | Flush Surface Finish in Counterbored Holes |
| Truss / Wafer Head (DIN 968) | Phillips (PH) / Pozi | ≥ 450 HV0.3 | 270 – 390 HV0.3 | Extra-Wide Low Profile Head to Prevent Thin Sheet Tear-Out |
Precision Cold Heading, Thread Rolling, and Case Hardening Process
At our manufacturing plant in Handan, China, self-tapping screws are forged, threaded, heat-treated, and plated on automated high-speed production lines:
- Multi-Station High-Speed Heading: Cold formers punch C1022A carbon steel wire into precise head shapes (Pan, Flat, Truss) and deep Phillips cross recesses without drive deformation.
- Precision Thread Rolling: High-speed thread rolling dies form sharp, uniform AB or A tapping thread profiles with sharp gimlet points that easily bite into base materials.
- Controlled Case Hardening Furnace: Screws pass through mesh-belt continuous carburizing furnaces to infuse carbon into the surface layer, establishing high anti-wear hardness without core embrittlement.
- Electro-Zinc Plating & Passivation: Trivalent chromium (Cr3+) electro-galvanizing applies a bright 5–10 µm protective zinc coating, followed by baking to eliminate hydrogen embrittlement.
Versatile Industrial Applications of Self Tapping Screws
Self-tapping screws provide rapid, reliable mechanical joining across diverse industrial assembly sectors:
- HVAC Ductwork & Sheet Metal Fabrication: Fastening thin galvanized sheet metal air ducts, access doors, and enclosure panels.
- Home Appliances & Electrical Cabinets: Securing internal plastic housings, circuit board brackets, and metal side panels in washing machines, refrigerators, and switchgear cabinets.
- Aluminum Windows, Doors & Furniture: Mounting hinges, brackets, and aluminum extrusion frames requiring high strip torque.
Quality Assurance and Export Packaging for Self Tapping Screws
Handan YiHao Fastener enforces strict Quality Assurance (QA) standards for all overseas export orders. Testing procedures include 100% drive recess depth gauge checks, surface and core Vickers hardness testing (HV0.3), driving speed test into standard steel plates, and salt spray validation.
All export items are bulk packed in heavy-duty 25kg inner cartons or 1000pcs small color boxes, neatly stacked on ISPM 15 compliant fumigated wooden pallets, and wrapped in protective stretch film for safe ocean freight.
Request Factory Direct Pricing for Zinc Plated Self Tapping Screws
Looking for a trusted manufacturer in Handan, China for carbon steel C1022A zinc-plated self tapping screws (DIN 7981 Pan, DIN 7982 Flat Countersunk, DIN 968 Truss Head)? Contact Handan YiHao Fastener today for technical datasheets, driving torque performance reports, free samples, and direct bulk export quotes.
