Release time：2020-01-16 18:44 Browse：
### 1. **Standard Compliance & Strength Grade**
- **DIN933 Certification**: Adheres strictly to DIN933, a German industrial standard governing fully threaded external hexagonal bolts. This ensures consistent dimensions (head width, height, thread pitch) and compatibility with DIN-matched nuts, washers, and tools—critical for seamless integration in global industrial supply chains.
- **Grade 8.8 High-Strength Performance**: Forged from medium-carbon alloy steel (typically with manganese and silicon additives) and heat-treated via quenching (rapid cooling) and tempering (controlled reheating). This process achieves a minimum tensile strength of 800 MPa and yield strength of 640 MPa, classifying it as a medium-high strength fastener. It excels in applications requiring resistance to heavy static/dynamic loads, such as structural brackets, machinery frames, or automotive chassis components.
### 2. **Design Features: External Hexagonal Head & Full Threading**
- **External Hexagonal Head**: Features a six-sided, flat-headed design with parallel flats, engineered for efficient torque transmission using standard open-end wrenches, socket sets, or power tools. The head’s standardized dimensions (e.g., width across flats proportional to bolt diameter) prevent slippage during high-torque installation, reducing the risk of stripped heads in demanding assembly lines.
- **Full Threading**: Unlike half-threaded bolts, the entire shank (from under the head to the tip) is precision-threaded per DIN933 specifications. This maximizes thread engagement with nuts or tapped holes, distributing clamping force evenly and enhancing stability in applications where the bolt must grip through multiple layers of material (e.g., stacked metal plates or composite structures).
### 3. **Surface Treatment: Black Zinc Coating**
- **Black Zinc Plating Process**: Undergoes electroplating to deposit a uniform black zinc layer (typically 5–25 μm thick) over the steel surface. The zinc acts as a sacrificial anode, corroding preferentially to protect the underlying steel from rust, moisture, and mild chemical exposure. The black finish is achieved via post-plating passivation (often with chromate or trivalent solutions), enhancing both corrosion resistance and aesthetic appeal.
- **Advantages Over Alternatives**: Offers better corrosion protection than basic black oxide (withstands 48–120 hours in salt spray tests, depending on coating thickness) and a more uniform, matte black appearance than hot-dip galvanizing. This makes it suitable for both functional (outdoor machinery, marine equipment) and semi-visible applications (industrial enclosures, where appearance matters alongside performance).
### 4. **Factory Direct Benefits & Application Scenarios**
- **Factory Direct Supply Advantages**: Sold directly from the manufacturing facility, eliminating middlemen to offer competitive pricing, shorter lead times, and bulk order flexibility (from small batches to container loads). Customers benefit from full traceability—access to material certificates, heat treatment records, and coating test reports—ensuring compliance with industry standards (e.g., ISO 898-1 for Grade 8.8).
- **Ideal Applications**:
- **Construction & Infrastructure**: Securing steel beams, scaffolding, or concrete formwork, where high strength and weather resistance are critical.
- **Automotive & Heavy Machinery**: Fastening engine components, transmission parts, or hydraulic systems, where vibration resistance and corrosion protection (from oils/fluids) are essential.
- **Industrial Equipment**: Assembling presses, conveyors, or manufacturing lines, where full threading ensures a tight, wobble-free fit in multi-part assemblies.
