Causes and Solutions for Accelerated Flash Rusting in Water-Based Coatings

What causes accelerated flash rusting?

1. Slow-drying conditions: Low temperatures and high humidity (particularly severe when RH exceeds 85%);

2. Impure or unstable iron substrates from poor pretreatment: Freshly treated steel surfaces are prone to flash rusting; rusted carbon steel, cast iron, and similar metals also develop flash rust after grinding;

3. Coating System: Lower pH values increase susceptibility to flash rust. To address this, adsorbent products are generally selected for water-based coating systems with lower pH values.

4. Susceptibility to flash rust on metal substrates, ranked: Metal welds (submerged arc welding) > Cast iron > Carbon steel > Galvanized steel sheet (ground) > Tinplate (ground) > Iron sheet or iron wire > Aluminum alloy.

How to Prevent Flash Rust?

1. Film Thickness: Thicker coatings are more prone to flash rusting, as increased film thickness drastically reduces moisture evaporation rates. For systems requiring thicker films, incorporate appropriate film-forming aids to enhance moisture evaporation.

2. Prevent metal substrate contamination. Prioritize substrates less susceptible to flash rusting and thoroughly cleanse substrates of oils and impurities.

3. Resin systems: Self-drying systems like styrene-acrylic or pure acrylic emulsions are prone to flash rust, whereas water-soluble acrylic and polyester resin systems are less susceptible.

4. Use anti-flash rust agents: Properly formulated anti-flash rust agents effectively prevent flash rust. Consider selecting adsorption-type, reaction-type, or precipitation-type agents.

Enze Flash Rust Inhibitor HY72 demonstrates outstanding flash rust suppression across various metal substrates, suitable for iron, cast iron, carbon steel, alloy steel, and other metals. It forms an adsorbed protective film on the metal surface, isolating the metal surface from corrosive media and inhibits rust formation. Compatible with all water-based coating systems, it synergizes with anti-corrosion pigments and exhibits excellent compatibility with coating systems, making it a highly efficient, versatile anti-flash rust agent. It does not affect coating drying speed or substrate adhesion, while enhancing the coating's rust prevention and salt spray resistance properties.