How do you prevent steel doors from rusting?

Every steel door leaf and frame starts as a hot-dip galvanised cold-rolled steel sheet. Before finishing it goes through a seven-stage pre-treatment line: degreasing, pickling, phosphate conversion and chromate-free passivation. The surface is then finished with polyester powder coating (60-80 microns) or optional fluorocarbon paint for coastal projects.

This system passes a 480-hour salt-spray test (ASTM B117) with no red rust, which is why we offer a 10-year corrosion warranty on the frame and leaf. Hinges, lock faceplates and pull handles are stainless steel 304/316 so the whole set ages consistently.