Flange Bolts Used in Construction: Key Requirements & Safety Standards

In construction projects, flange bolts are not just ordinary fasteners. They are often used in structural steel connections, equipment foundations, guardrail systems, and heavy-duty assemblies where stability and load distribution matter. Compared with standard hex bolts, a flange bolt has an integrated washer-like base that increases the bearing surface, which helps reduce loosening and surface damage in demanding jobsite conditions.

When used correctly, flange bolts improve joint reliability and long-term safety. But in construction applications, meeting technical requirements and safety standards is critical. As a professional fastener manufacturer, Xinchi is pleased to introduce for you.

Flange Bolts in Construction Applications

In real construction scenarios, flange bolts are commonly used to connect steel beams, brackets, machinery bases, and prefabricated components. The built-in flange helps distribute clamping force more evenly, especially when fastening to steel plates or structural members.

Because construction environments often involve vibration, dynamic loads, and outdoor exposure, the selected flange bolt must match the structural design. It’s not just about size — strength grade, surface treatment, and torque control all influence performance on site.

Strength Grade Requirements for Construction Flange Bolts

For structural use, the strength grade of the flange bolt is one of the first things engineers check. In many steel structure projects, grades such as 8.8, 10.9, or even higher are specified depending on load requirements.

A construction-grade flange bolt must provide sufficient tensile strength and shear resistance. If the grade is too low, bolt failure can occur under dynamic loading. On the other hand, using unnecessarily high grades without proper torque control can also create installation issues. Matching the bolt grade to the structural calculation is standard practice in responsible construction work.

Surface Treatment and Corrosion Protection of Flange Bolts

Most construction flange bolts are exposed to outdoor environments. Moisture, temperature changes, and industrial pollution can accelerate corrosion. That’s why surface treatment is not optional.

Common finishes for flange bolts in construction include zinc plating, hot-dip galvanizing, and other anti-corrosion coatings. For outdoor steel structures, hot-dip galvanized flange bolts are often preferred because of their thicker protective layer. Proper corrosion resistance ensures the joint maintains clamping force over time.

Torque Control and Installation Standards for Flange Bolts

Even the best flange bolt can fail if installation is not done properly. Construction standards typically specify tightening torque or preload requirements to ensure structural safety.

Over-tightening a flange bolt may damage threads or reduce fatigue life. Under-tightening increases the risk of loosening, especially in vibration-prone structures. That’s why torque control tools and standardized procedures are widely used on construction sites.

In critical applications, regular inspection of flange bolt connections is also part of safety management, especially for bridges, steel frameworks, and heavy equipment supports.

Quality Control Standards for Construction Flange Bolts

Before flange bolts enter a construction project, they should meet relevant mechanical and dimensional standards. This usually includes tensile testing, hardness testing, thread accuracy inspection, and coating thickness verification.

Reliable flange bolt suppliers understand that construction fasteners are safety-related components. Consistency in material selection and cold forming quality directly affects performance in the field.

Xinchi Fasteners Factory–Since 2007

Xinchi Fasteners Factory was established in 2007 and focuses on the manufacturing of various industrial fasteners, including flange bolts for construction applications. Our factory operates 102 cold-heading machines, with a daily production capacity exceeding 10 million pieces. The newly completed production facility covers 30,000 square meters and includes two six-story buildings, allowing us to maintain stable mass production and efficient order fulfillment.

With strong cold-forming capability and strict internal quality control, Xinchi supplies flange bolts with consistent dimensions, stable mechanical performance, and reliable delivery schedules. As a trusted fastener supplier, Xinchi offers a wide range of high-quality fasteners, including nuts, screws, bolts, rivets, and washers. We focus purely on fasteners, ensuring professional manufacturing without mixing with furniture or other unrelated projects.