As a common fastener, the core functions and features of the Torx screw with a half-thread insert (a national standard stainless steel pan head machine screw with a washer) can be systematically summarized below.
1. Core Function
High-Strength Fastening Connections
Half-thread design: The threaded portion only covers the lower half of the screw shaft, leaving the upper half polished for easy insertion and positioning. This design is suitable for applications that require partial engagement and prevent damage to the material caused by over-threading.
Machine Thread: Precision-machined threads that comply with national standards provide high fit accuracy and shear resistance, ensuring a secure connection.
Anti-Loosening and Pressure Distributor
Integrated Washer (with insert): A flat washer is integrated under the pan head to increase contact area, distribute the clamping force, and prevent loosening or surface markings. It is particularly suitable for soft materials such as aluminum alloy and wood.
Torx Drive: Compared to a cross-slot drive, the Torx drive offers higher torque transmission efficiency and reduces the risk of slippage, making it suitable for automated assembly or high-strength fastening applications.
Corrosion Resistance and Durability
Stainless Steel: Austenitic stainless steel offers excellent resistance to rust, acids, and alkalis, making it suitable for humid, chemical, and outdoor environments.
Quick Assembly and Aesthetics
Pan-Head Design: The raised pan head facilitates manual or power tool operation, while the sleek appearance makes it suitable for exposed installation.
Pre-Assembled Washers: Reduce the need for separate washer installation, improving assembly efficiency.
II. Key Applications
Electronic and Electrical Equipment: PCB mounting and housing assembly (half-thread prevents damage to internal components).
Mechanical Equipment: Panel and bracket connection (stainless steel resists oil and corrosion).
Automotive Accessories: Interior component installation (locking washers prevent vibration and dislodging).
Outdoor Furniture: Guardrails and signage (weather resistance extends service life).
III. Key National Standards and Parameters
Standards Based on: GB/T 818 and GB/T 94.1.
Typical Specifications: M3-M12, Length 10-100mm (half-thread ratio is typically 1/2 or 2/3 of the screw length).
Performance Grade: A2-70 (stainless steel tensile strength 700 MPa).
IV. Selection Considerations
Material Matching: Avoid galvanic corrosion caused by direct contact between stainless steel and aluminum; an insulating washer may be used.
Torque Control: The hexagonal socket must be used with a Torx bit; overloading can damage the notch.
In summary, this screw's design combines a half-thread design to prevent overtightening, a washer to prevent loosening, stainless steel corrosion resistance, and a hexagonal socket for efficient drive, achieving high reliability and wide applicability. It is a key fastening solution for both industrial and civilian applications.
