What Are the Anti-Rust Measures for Expansion Anchor Screws During GRC Component Installation? Detail Protection and Qinglong Group Construction Control

Rust prevention for the chemical anchors or expansion bolts (colloquially known as "expansion anchor screws") used in GRC component installation is a key detail for preventing connection failure, and the four-step standardized operation of "material upgrade, hole treatment, torque control, and end protection" must be implemented. Qinglong Group's construction specifications require: in damp or outdoor environments, A2-70 or A4-80 stainless steel bolts must be selected; after drilling, holes must be thoroughly cleaned with a high-pressure air gun and injected with special anti-corrosion anchoring adhesive; a torque wrench must be used to tighten bolts to the design value, avoiding over-tightening that could damage the coating; exposed bolt ends and washers must be coated with epoxy zinc-rich paint or fitted with plastic protective caps. In the post-evaluation of a riverside commercial project in Nanning, carbon steel bolts without end protection reached a 30% corrosion rate within 5 years, while the stainless steel bolts installed to our standards remained as good as new after ten years. Small screws, big safety—rust prevention is never a trivial matter.

Bolt Material Is the First Line of Defense Against Rust

The use of ordinary carbon steel bolts is strictly prohibited in GRC curtain wall projects. Hot-dip galvanized bolts (grade 8.8) may be used in dry indoor environments, while stainless steel bolts (austenitic 304 or 316) must be used outdoors and in damp environments. Qinglong Group verifies the material certificates for every batch of bolts entering the site and conducts on-site salt spray test spot checks.

Anchor Hole Treatment and Adhesive Injection Are the Core Process

If the powder produced by drilling is not removed, it will absorb moisture and accelerate bolt corrosion. We require "three blows and two brushes" to ensure the hole is clean. The injected chemical anchoring adhesive or epoxy mortar not only provides anchoring force but also encapsulates the bolt, isolating it from air and moisture. A glue gun must be used to fill the hole from the bottom.

Tightening and Protection Are the Final Safeguard

Use a calibrated torque wrench for tightening, ensuring uniform preload without damaging the threads. After the bolts are tightened, immediately apply anti-corrosion coating to all exposed metal parts such as threads, washers, and nuts. For completed areas, fit plastic protective caps in colors coordinated with the GRC, which both prevent rust and look aesthetically pleasing.

No matter how good the design, it cannot withstand the erosion of rust. Qinglong Group treats bolt rust prevention as a construction quality control point, incorporating it into the work instructions and conducting special acceptance inspections.