Countersunk Head SelfTapping Screws China Factory Suppliers DIN 7982 ISO 7050
Longze Cross Recessed Countersunk Head Self-Tapping Screws, also recognized as Phillips Flat Head Sheet Metal Screws, are high-precision industrial fasteners engineered to meet rigorous DIN 7982, ISO 7050, and ASME B18.6.3 international standards. Designed with a precise 90° countersunk head, these screws ensure a flush profile that sits level with or below the material surface, making them the premier choice for applications where a smooth, snag-free finish is critical for safety and aesthetics.
Optimized for high-speed assembly, these fasteners feature a deep cross recess to minimize cam-out and extend driver bit lifespan. Whether securing thin sheet metal, dense plastics, or structural aluminum, Longze's case-hardened thread technology allows the screw to carve its own mating thread with exceptional strength and durability, providing a reliable structural bond across diverse industrial and consumer substrates.
Detailed Parameters
| Technical Standards | DIN 7982, ISO 7050 (Metric) / ASME B18.6.3 (Inch) | Drive Type | Phillips (Cross Recess) / Pozidriv |
|---|---|---|---|
| Metric Size Range | ST2.2 to ST9.5 (Diameter 2.2mm - 9.5mm) | Inch Size Range | #2 to 3/8" (Diameter 0.086" - 0.375") |
| Length Options | 4.0 mm to 150 mm (1/8" to 6") | Point Styles | Type AB (Pointed), Type B (Blunt) |
| Material Options | Case-Hardened Carbon Steel, Stainless Steel A2, A4 | Head Angle | Precision 90° Countersunk |
| Surface Treatment | Zinc Plated, Black Oxide, Nickel Plated, Passivated | Hardness (Carbon) | Surface: HV 450 min / Core: HV 270 - 390 |
Key Advantages
Case-Hardened Strength
Heat-treated threads penetrate structural aluminum and steel sheets without blunting, ensuring maximum shear resistance.
Rapid Installation
Phillips drive is optimized for power tools, providing centered engagement and drastically reducing assembly cycle times.
Flush Profile Finish
The 90° head angle guarantees seamless seating in countersunk holes, eliminating sharp edges and surface gaps.
Anti-Cam-Out Design
Deep cross recess geometry prevents premature driver slip, protecting both the workpiece surface and the tool bit.
Material Versatility
Engineered for multi-substrate compatibility, from thin-gauge sheet metal to high-density industrial plastics.
Global Compatibility
Strict adherence to ISO and ASME standards ensures 100% interchangeability across international engineering projects.
Product Gallery
Management Platforms
Quality Certification
ISO 9001 certified production ensuring consistent thread pitch and recess geometry across all batches.
Hydrogen Relief
Specialized baking process for zinc-plated case-hardened screws to prevent hydrogen embrittlement.
Precision Conversion
Expert metric-to-inch conversion services to meet exact global engineering and architectural needs.
Coating Control
Rigorous salt spray testing (up to 1000h+) to guarantee corrosion resistance in marine environments.
Export Logistics
Standardized 25kg export cartons on fumigation-free pallets for secure international shipping.
Tech Support
Direct engineering consultation for pilot hole sizing, torque control, and material selection.
Investment Return Comparison
| Surface Treatment | Salt Spray Life | Recommended Environment |
|---|---|---|
| Zinc Plated | 72 - 144 Hours | Indoor / General Hardware |
| Black Oxide | 24 - 48 Hours | Electronics / Interior Trim |
| Nickel Plated | 48 - 96 Hours | Decorative Furniture |
| Passivated (SS) | 1000+ Hours | Marine / Medical / Chemical |
| Case-Hardened Steel | Varies by Coating | Structural Industrial Use |
Frequently Asked Questions
Yes, however, Longze recommends pre-drilling a pilot hole slightly deeper than the screw length to prevent the wood from splitting due to the high-strength threads.
Type AB features a fine thread and a pointed tip optimized for thin sheet metal, while Type B has a blunt tip designed for slightly thicker materials.
Ensure the countersink depth matches the head geometry; a shallow countersink will leave sharp edges, while an over-deep one may weaken the material.
We highly recommend Stainless Steel A4 (316), which is work-hardened and specifically engineered for acid and marine resistance.
Use clutch-driven power tools to maintain precise torque control, avoiding over-tightening which can strip threads in soft substrates.
Yes, all our zinc-plated case-hardened screws undergo a professional baking process to relieve hydrogen and ensure long-term structural reliability.
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