Wholesale Black Security Screw Supplier & Factory

Flaking usually occurs when surface treatments deposit an excessively thick, brittle crystalline layer or when pre-plating degreasing is insufficient. We utilize micro-conversion black zinc and chemical black oxide techniques that chemically react with the underlying iron matrix rather than forming an unbonded topical paint layer. Furthermore, drive recess geometries are compensated during tooling design to maintain class-leading dimensional tolerance even after coating deposition.

Yes. A significant percentage of our custom output consists of customer-proprietary drive recesses designed to prevent unauthorized field access. We execute robust Non-Disclosure Agreements (NDAs), manufacture carbide heading punches in-house via high-precision wire EDM, and restrict driver bit access exclusively to the OEM purchaser's verified logistics channels.

Black Oxide (MIL-DTL-13924) is an alkaline conversion coating producing Magnetite (Fe3O4) with zero dimensional build-up (<0.001mm), perfect for high-precision optical and internal machine tolerances; its corrosion resistance relies on supplemental oil. Black Trivalent Zinc is an electroplated sacrificial layer (5-12 microns) that provides anodic protection, passing 120 to 720+ hours of Neutral Salt Spray testing, ideal for outdoor enclosures and automotive parts.

High-strength carbon and alloy steels (≥1000 MPa tensile strength or ≥320 HV hardness) are prone to hydrogen atomic migration during acid pickling and electroplating. We follow strict IATF 16949 de-embrittlement protocols: parts enter convection baking ovens within 4 hours post-plating, maintaining 200°C ± 5°C for 8 to 24 hours depending on fastener diameter and strength classification.