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Electro-galvanized hexagonal drill thread
Made of 1022A carbon steel, the surface hardness reaches HV560-750 after heat treatment, and the core hardness reaches HV240-450. The surface is electro-galvanized to form a 5-12μm coating, which meets the GB/T 13912-2002 standard, and the salt spray test reaches 24-48 hours without white rust.
Description
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Product Introduction
Material and process: Made of 1022A carbon steel, the surface hardness reaches HV560-750 after heat treatment, and the core hardness reaches HV240-450. The surface is electro-galvanized to form a 5-12μm coating, which meets the GB/T 13912-2002 standard, and the salt spray test reaches 24-48 hours without white rust.
Structural design: The head is hexagonal, suitable for socket wrenches, and provides high torque transmission capacity; the tail self-drilling drill bit can directly penetrate 3-6mm thick steel plates, thread specifications ST3.5-ST6.3, length 19-150mm.
Performance characteristics: tensile strength ≥ 600MPa, shear strength ≥ 450MPa, suitable for heavy-load scenarios such as steel structure and mechanical equipment installation. The maximum static force of M5 specification in Q235 steel plate is about 12kN.
Application scenarios: building steel structure purlin connection, color steel tile fixing, shelf installation, etc., especially suitable for indoor dry environment.
Key comparison and selection recommendations
| Type | Surface treatment | Salt spray test | Hardness range | Corrosion resistance | Environmental protection | Typical application scenarios |
| Electro-galvanized hexagonal head | Silvery white | 24-48 hours | HV560-750 | General | No hexavalent chromium | Indoor steel structure, ordinary mechanical connection |
| Colored zinc-plated hexagonal head | Rainbow color | More than 72 hours | HV580-720 3 | Good | Trivalent chromium environmental protection | Outdoor photovoltaic bracket, port equipment |
| Black zinc-plated hexagonal head | Black | More than 96 hours | HV600-700 | Excellent | Trivalent chromium environmental protection | Automobile chassis, high-temperature equipment |
| Electro-galvanized cross countersunk head | Silvery white | 24-48 hours | HV580-720 | General | No hexavalent chromium Indoor decoration, furniture manufacturing | Colored zinc-plated cross countersunk head |
| Rainbow color | More than | 72 hours | HV580-720 | Good | Trivalent chromium environmental protection | Outdoor awnings, bathroom equipment |
Selection suggestions:
Environmental factors: For outdoor or high humidity environments, color zinc plating or black zinc plating is preferred; for indoor dry environments, electroplating zinc can be selected.
Load requirements: For high-load scenarios (such as bridges and heavy machinery), black zinc-plated hexagonal drill tail screws must be selected. Specifications above M8 must be tested for torque according to GB/T 3098.11.
Environmental requirements: Electroplating zinc (chromium-free) is recommended for the medical and food industries; trivalent chromium passivated color zinc plating or black zinc plating can be selected for ordinary industrial projects.
Installation specifications:
Electric drill speed control: 3.5mm diameter drill tail screws are recommended to be 1800-2500 rpm, and 5.5mm diameter drill tail screws are recommended to be 1000-1800 rpm.
Torque control: The torque of the M4 specification is about 24-28kg・cm, and the M6 specification is about 61-70kg・cm. Avoid deformation of the substrate due to excessive tightening.
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