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304 Stainless Steel and Carbon Steel Countersunk Expansion Bolts - Heavy Duty Window Frame Sleeve Anchor from China Suppliers and Factory

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Product Name: Window Frame Sleeve Anchor / Countersunk Cross Recessed Expansion Bolt
, Material: Crafted using a dual-material composite process
, Standards: Complies with ETAG 001 and GB/T 22795 standards
, Grade: Carbon Steel available in 4.8 and 8.8 grades; Stainless Steel available in A2-70 (304)
, Specifications: Sizes ranging from M6 to M16, with customization options for lengths from 50mm to 200mm
, Surface Treatment: Carbon Steel options: Blue-white zinc, environmentally friendly color zinc, yellow color zinc; Stainless Steel: 360° electrolytic polishing or natural brushed finish
, Design Features: Innovative countersunk cross groove design, extended gap for expansion, enhanced interlocking diamond/anti-slip texture, composite rust prevention, and superior tensile and shear strength
, Applications: Perfect for door and window installations, curtain wall systems, railing and handrail fixing, building decoration keels, air conditioning units, and electromechanical equipment, suitable for solid brick and concrete substrates
, Delivery Time: 15-30 days upon advance payment confirmation
, Origin: China
, Brand: JGD
, Minimum Order Quantity: 10,000 pieces, negotiable
, Samples: Available upon request
, Packaging: Offered in box, bulk, pallet, or customized packaging
, OEM Services: Available
, As a leading factory and one of the top suppliers in China, we are committed to providing high-quality expansion bolts tailored to your needs.

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    304 Stainless Steel Cross Recessed Countersunk Head Self-Tapping Screws01
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    304 Stainless Steel Cross Recessed Countersunk Head Self-Tapping Screws01

    Key Features

    Our self-tapping screws are crafted from food-grade 304 stainless steel and treated to achieve metric Grade 12.9 ultra-high strength, overcoming the traditional hardness limitations of standard stainless steel. Featuring a countersunk Phillips head design, these screws can be installed flush with the workpiece surface for a zero-profile finish, making them ideal for precision electronics and architectural decoration. We have optimized the thread geometry for different substrates (metal, wood) to ensure low-torque driving with high-torque clamping, effectively preventing stripping. As a superior alternative to standard Tek screws, these fasteners perform exceptionally well in thin sheet metal connections, providing an intelligent fastening solution that balances aesthetics with high load-bearing capacity.
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    Precision Manufacturing Process

    From wire rod to finished product, we strictly adhere to multiple international standards including ISO, DIN, ANSI, and GB. Utilizing multi-station cold forging technology, we ensure shank diameter tolerances are controlled within microns. Threads are formed through a precision thread rolling process to enhance fastening force. For non-standard requirements, we employ optical imaging sorters to reject minute defects like head cracks. In post-treatment, we offer a wide range of surface finishing options: from conventional zinc plating and nickel plating to highly corrosion-resistant Hot-Dip Galvanizing (H.D.G.), as well as decorative polishing and black anodizing. We even provide food-grade passivation treatment, ensuring every screw has a prolonged fatigue life in demanding environments.
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    Transparency & Customization

    As a source factory, we are committed to breaking down the information barriers of traditional trade. From mill certificates for raw materials to hardness grades (covering Grade 4.8 to Grade 12.9, as well as A2-70 and A4-80 marine-grade stainless steel), all test data is traceable. We support full-chain customization: dimensionally, we can adjust thread length and head thickness according to drawings; functionally, we can combine processes like sandblasting, electrophoretic coating (e-coating) , or chrome plating. Whether you need British Standard (BS) fasteners or require a special colored anodized finish, we offer small-batch sampling. This ensures that when you purchase fasteners from us, you not only receive high-quality products but also full transparency and control over the entire process, from material selection to packaging.
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    No Pre-Drilling · Rust Resistant · More Secure

    This stainless steel Phillips countersunk self-tapping screw, with its rust-resistant and corrosion-resistant material, one-step self-tapping design, and aesthetically pleasing countersunk head structure, has become the preferred solution for metal substrate fastening scenarios that is efficient, reliable, and aesthetically pleasing.
    Product Details

    Manufacturing Process

    Manufacturing Process

    • Multi Station Cold Heading Technology
    • Intelligent Heat Treatment System
    • Micron-Level Thread Rolling Process
    • Fully Automatic Optical Sorting
    • Environmentally Friendly Surface Treatment Line
    • Metallographic And Mechanical Joint Laboratory
    Quality Control System

    Quality Control System

    • Raw Material Source Locking
    • Furnace Number Batch Full Traceability
    • Third Party Material Certification
    • Process Parameters Open And Transparent
    • Salt Spray Test Real Time Monitoring
    • International Standard Compliance Declaration
    Flexible Customization Capability

    Flexible Customization Capability

    • Customizable head/slot Shapes
    • Extreme Application Of Special Materials
    • Breakthroughs In Extra Large/Long Specifications
    • Integrated Assembly Of Components
    • Customizable Surface Treatment Colors
    • Personalized Packaging And Labeling
    Technical Service

    Technical Service

    • On-Site Failure Analysis
    • Selection Calculation And BOM Optimization
    • Installation Tool Selection Guidance
    • Inventory Management (VMI) Trusteeship
    • Free Sample Making And Testing
    • International Standard Translation And Interpretation
    Dual-Material Composite
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    Dual-Material Composite – Corrosion Resistance Inside & Out

    Made with a dual-material process: the sleeve is high-strength carbon steel (Grade 4.8/8.8) or 304 stainless steel, while all internal expansion wedges and screws are 304 stainless steel. This design ensures high tensile strength and rigidity from the sleeve, while critical threaded and wedge parts never rust. Even under long-term exposure to window condensation, rain, or humid conditions, internal components remain flexible and reliable – no seizing or failure due to corrosion.
    Countersunk Cross Recess
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    Countersunk Cross Recess + Diamond Knurling – Flush Fit & Anti-Loosening

    The countersunk cross recess allows the head to fully embed into the workpiece surface, sitting flush with window frames and curtain wall profiles – aesthetic and never obstructing window operation. Long expansion slots combined with high-grip diamond/anti-slip textures enable 360° uniform expansion tightly against the hole wall, delivering excellent tensile and shear strength. Cross drive works with impact wrenches for easy installation, while diamond textures effectively resist vibration loosening – ideal for outdoor windows and doors subject to wind loads.
    Long-Lasting Wear Resistance
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    Long-Lasting Wear Resistance for Harsh Climates

    Internal 304 stainless steel components are electrolytically polished for a smooth, wear-resistant surface; carbon steel sleeves are zinc-plated for overall superior fatigue performance. Proven in cyclic load tests, this anchor withstands decades of window vibration, temperature swings, and weather erosion without failure. The countersunk head is burr-free, protecting sealing gaskets. Compared to ordinary expansion bolts, replacement intervals are greatly extended – providing lifelong reliable anchoring for building curtain walls and premium windows and doors.

    Factory Environment

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    High-Quality Stainless Steel Self-Tapping Screw Display

    Frequently Asked Questions

    What materials are used in the dual-material composite anchors?
    The sleeve is made of high-strength carbon steel (Grade 4.8/8.8) or 304 stainless steel, while the internal expansion wedges and screws are entirely constructed from 304 stainless steel. This prevents internal corrosion and thread seizing.
    How does the countersunk cross recess head benefit window installations?
    The countersunk cross recess head embeds fully flush into the workpiece surface, ensuring it sits flat against window frames and curtain wall profiles. This design prevents any obstruction to the window operations and offers a neat, aesthetic finish.
    What features prevent these anchors from loosening over time?
    The design utilizes long expansion slots paired with high-grip diamond and anti-slip textures. This combination achieves a 360-degree uniform expansion against the hole wall, offering high resistance to wind load vibrations and loosening.
    Can these self-tapping screws and components be customized?
    Yes, we offer flexible customization capabilities. We can customize head and slot shapes, manufacture extra-large or extra-long specifications, apply custom surface treatment colors, and provide personalized packaging and labeling.
    How is the quality of these products monitored and controlled?
    Our quality control system locks raw material sources, provides full traceability via furnace batch numbers, secures third-party material certifications, and performs real-time monitoring of salt spray tests to ensure international standard compliance.
    Are these products suitable for harsh outdoor environments?
    Absolutely. The internal 304 stainless steel components are electrolytically polished for wear resistance, and carbon steel sleeves are zinc-plated to withstand cyclic wind loads, extreme temperature variations, and wet or humid conditions.