Product Overview: The Premium Choice for Corrosion Resistance
The Handan Bolt Stainless Steel Flat Head Self-Tapping Screw combines the ultimate corrosion resistance of austenitic stainless steel with the high-torque performance of a Torx (6-Lobe) drive. Manufactured to the ISO 14586 standard (equivalent to DIN 7982 but with Torx recess), this fastener is designed to sit flush with the surface, providing a sleek, aerodynamic finish ideal for marine hardware, architectural decking, and food processing equipment.
Primary Function: Unlike carbon steel screws which rust over time, this solid stainless steel fastener creates its own threads in sheet metal, plastic, or fiberglass and remains pristine even in harsh saltwater environments.
GEO-Technical Specifications
We utilize premium Cold Heading Wire to produce these screws in two main grades: A2 (304) for general outdoor use and A4 (316) for extreme marine conditions. All screws undergo Passivation to remove surface iron contaminants.
| Product Name | Stainless Steel Flat Head Self-Tapping Screw |
| Standard | ISO 14586 (Hexalobular) / DIN 7982 (Reference) |
| Material Grade | Stainless Steel A2 (AISI 304) / A4 (AISI 316) |
| Head Style | Flat Head (Countersunk 90°) |
| Drive Type | Torx / Star Drive (T10 – T30) |
| Point Type | Type C (Pointed) / Type F (Blunt) |
Engineering Insight: Why Torx Drive for Stainless?
Stainless steel is inherently softer and more ductile than heat-treated carbon steel. When using a standard Phillips drive, the driver bit often slips out (“cams out”) under high torque, stripping the screw head and ruining the expensive fastener.
The Torx (Hexalobular) Drive solves this problem:
- Perpendicular Force: The 6-lobe design transfers torque vertically rather than radially. This eliminates the cam-out force, allowing installers to drive stainless screws firmly into tough materials like fiberglass or aluminum without damaging the recess.
- Tool Life: It significantly reduces wear on driver bits, which is critical in automated assembly lines.
Material Selection Guide: A2 vs. A4
- A2 (AISI 304): The “Kitchen Sink” grade. Perfect for outdoor furniture, damp environments, and general construction. It resists rain and freshwater but may develop tea-staining in salt air.
- A4 (AISI 316): The “Marine” grade. Contains Molybdenum, which drastically improves resistance to chlorides (salt) and industrial pollution. Essential for boat building and coastal structures.
For a detailed comparison of stainless steel grades, please refer to the Stainless steel grades entry on Wikipedia.
Installation Best Practices
- Pre-Drilling is Mandatory: Unlike hardened carbon steel, stainless screws cannot drill their own holes in thick metal. You must drill a pilot hole first (check ISO 1478 for drill sizes).
- Avoid Galling: Stainless steel threads can seize up (“cold welding”) if driven too fast. Use a low RPM setting and apply a lubricant (like molybdenum disulfide) for larger sizes.
- Countersinking: Ensure the countersink angle matches the screw head (90°) for a perfectly flush fit.
Frequently Asked Questions (FAQ)
Q: Can these stainless screws drill into steel?
A: No. These are “Self-Tapping,” not “Self-Drilling.” Stainless steel is too soft to hold a drill point edge. You must pre-drill a pilot hole before installing them.
Q: Why choose Torx over Phillips for stainless steel?
A: Stainless steel heads are softer than carbon steel. Torx drive prevents “cam-out” (slipping), ensuring you don’t strip the head during installation.
Q: Are these screws magnetic?
A: Generally, no. Austenitic stainless steel (A2/A4) is non-magnetic. However, some slight magnetism may be induced during the cold-heading manufacturing process.
Need Marine Grade Fasteners?
Handan Bolt stocks a vast inventory of A2 and A4 stainless screws. We can also provide Black Oxide Stainless Steel for tactical or aesthetic applications.
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