Dakro Round Head With Square Neck Bolts

Product introduction

Dacromet round head bolt with square neck is a high-performance fastener that combines unique structural design and top-notch surface treatment technology. Its round head design makes it easy to disassemble and install using conventional tools, while the square neck under the stem is its core function. During installation, the square neck can be tightly embedded in the preset hole slot of the connected part, effectively preventing the bolt from rotating during the tightening of the nut, thereby enabling efficient and convenient assembly by one person, greatly improving construction efficiency. The most significant advantage of this product is its surface "Dacromet" coating (also known as zinc chromium coating). This is an electrolytic coating process that gives bolts super corrosion resistance, and its rust prevention ability is far superior to traditional electrolytic zinc plating. At the same time, the coating can withstand high temperatures (up to 300°C) without the risk of hydrogen embrittlement, making it especially suitable for critical parts that require extremely high safety and durability. Therefore, it is widely used in harsh environments such as automobile manufacturing, rail transit, highway bridges, power towers, outdoor steel structures, etc. It is an ideal solution to achieve high strength, high corrosion resistance, and anti-loosening connections.

 

Product features

1. Excellent anti-rotation design

The square neck of the bolt shank is a central feature. During installation, the square neck will be tightly embedded in the prefabricated holes of the connected parts, which can effectively prevent the bolt from rotating when the nut is tightened. This design allows a single person to easily complete the installation without using additional tools to fix the bolt heads, which greatly improves assembly efficiency.

 

2. Excellent corrosion resistance

The Dacromet coating used on the surface is its key advantage. This coating forms an extremely thin and dense zinc-chromium film through an electrolytic process. Its anti-rust ability is 7-10 times that of traditional electrolytic zinc plating. It can withstand salt spray for hundreds of hours and can resist the erosion of moisture, salt spray, acid rain and other harsh environments for a long time.

 

3. Excellent high temperature resistance and no hydrogen embrittlement

Dacromet coating can withstand high temperatures of 300°C, making it suitable for high-temperature applications such as around engines and braking systems. At the same time, there is no pickling or electrolysis in the entire treatment process, which fundamentally eliminates the risk of "hydrogen embrittlement" and ensures the safety and reliability of the bolts under high-intensity stress conditions.

 

4. High strength fastening connection

The round head design provides sufficient bearing surface, which combined with the anti-rotation function of the square neck ensures the stability and reliability of the connection. The bolt body is usually made of high-strength steel and can withstand high preload and shear forces.

 

5. Comprehensive protection capabilities

Dacromet coating can cover every corner of the bolt without any dead ends, including complex parts such as the thread bottom, forming a uniform protective layer, avoiding the "dead corners" or "blind spots" problems that may exist in electroplating, and providing more comprehensive protection.

 

Product application

1. Transportation field

Automobile industry: Widely used in engine mounts, chassis structures, suspension systems and body connections. Its square-neck anti-rotation feature facilitates installation in tight spaces, while the Dacromet coating effectively resists corrosion from road salt, rain, snow and oil, and withstands the high temperatures of the engine compartment. Rail transit: used for the internal structure of locomotives and carriages, equipment installation, and trackside signaling facilities. Its high strength and weather resistance ensure the long-term safety and reliability of the connection.

 

2. Outdoor infrastructure and steel structures

Power and communication tower: It is a key connector for high-voltage transmission towers and communication base station towers. The Dacromet coating provides excellent resistance to atmospheric corrosion and UV rays, while the square neck design facilitates fast and safe installation at high altitudes. Highway bridges: used for fixing guardrails, soundproof screens, maintenance channels and other ancillary facilities, and can withstand long-term vibration loads and outdoor weathering.

 

3. Heavy machinery and equipment

Commonly used in sheet metal parts, protective covers and structural connections of construction machinery, agricultural machinery and mining equipment. Its anti-rotation feature simplifies maintenance work in the field, and its strong anti-corrosion capability can cope with corrosive media such as mud, water, and chemical fertilizers.

 

4. Architecture and Structural Engineering

It is suitable for fixing steel structure buildings that require high weather resistance, such as exterior wall panels and roof panels of warehouses and factories. It can be installed quickly and ensure that the connection points will not loosen or rust under years of wind and rain erosion.

 

FAQ

Q: What is the specific function of the "square neck" of this bolt?

A: The square neck is the core functional design. When installed, the square neck will fit into the pre-punched or drilled square hole of the connector, effectively preventing the bolt from rotating when the nut is tightened. This enables one-person operation without the need for a second wrench on the bolt head, greatly improving assembly efficiency.

 

Q: What are the advantages of "Dacromet" treatment compared with traditional galvanizing?

A: Dacromet is a revolutionary surface treatment technology. Its main advantages include: Super corrosion resistance: The anti-rust ability is more than 7-10 times that of traditional galvanizing, and it is especially good at resisting salt spray corrosion. No risk of hydrogen embrittlement: The treatment process does not require pickling and electrolysis, which is crucial for high-strength steel, and avoids the risk of bolt breakage due to hydrogen embrittlement. Excellent heat resistance: The coating can withstand high temperatures of 300°C for a long time without discoloration or failure. Good permeability: It can cover complex parts such as threads and grooves without dead ends, forming a uniform and dense protective layer.

 

Q: Why is it particularly suitable for use in car chassis and outdoor towers?

A: Because these two application scenarios perfectly match its core characteristics: Automobile chassis: harsh environment (vibration, salt spray, water vapor, high temperature), requiring high corrosion resistance and anti-vibration and anti-loosening capabilities. The anti-rotation and high strength of the square neck ensure reliable connection, and the Dacromet coating provides long-term protection. Outdoor towers: They are exposed to wind, rain and atmospheric corrosion for a long time, and are difficult to install and maintain. Dacromet's long weather-resistant life reduces maintenance requirements, while the square neck design greatly facilitates high-altitude operations and improves installation safety and efficiency.

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