FIELD: protective coatings.
SUBSTANCE: invention relates to protective varnish compositions that can be used as anticorrosive protection of low-carbon steel articles operated under various climatic conditions. Composition contains 105-150 g/L of special-destination varnish, which is 68±2% diacetone and isopropyl alcohol solution of phenol resin-modified maleized polybutadiene; 4-7 mL/g of 25% aqueous ammonia; 0.1-0.3 ml/g of ethanol; and isopropyl alcohol/water mixture (1:1 or 1:2) to 1 L. Method comprises following operations: degreasing, rinsing with cold running water, etching, rinsing with cold running water, clarification, rinsing with cold running water, phosphatation in solution containing 18-21 g/L zinc oxide, 80-85 g/L orthophosphoric acid, and 1-2 g/L sodium nitrate (pH of solution 2.7-3.2), rinsing with cold running water, activation during 3-5 min in solution containing 3-5 ml/g orthophosphoric acid and 5-10 g/L additional surfactant (OP-7 or OP-10), followed by drying for at least 5 min, immersion-mediated deposition of protective composition for 2-4 min at 15-35°C, reactivation in the same activating solution for at least 3 min, rinsing with cold running water, removing moisture drops, and drying for at least 1.0 h at 140-180°C.
EFFECT: enhanced corrosion resistance.
2 cl, 3 ex
