| 摘要 |
Multi-stage method for applying a weldable scaling protective layer on steel, comprises initially producing a metal pigment-free silicate thin film on the metallic steel surface, and subsequently applying and curing a wet film of a curable pigment containing coating. The curable pigment containing coating comprises a binder dissolved in a liquid phase, hydrolyzate and/or condensate of at least one silane/siloxane and/or at least one silicone resin. At least one metallic pigment of aluminum and at least one metallic pigment of bismuth are respectively present in particulate form. Independent claims are also included for: (1) a curable pigment containing coating composition for applying the weldable scaling protective layer on steel comprising (a) 10-40 wt.%, preferably 20-35 wt.% at least one silicone resin, (b) 10-30 wt.%, preferably 15-25 wt.% particulate aluminum, (c) 1-10 wt.%, preferably 2-7 wt.% particulate bismuth, (d) 20-60 wt.%, preferably 30-50 wt.% organic solvents, (e) less than 5 wt.% water, and (f) less than 5 wt.% additional coating additives comprising pigments, fillers, flow control agents, anti-settling agents or rheological additives, where the weight ratio of the metallic pigments of aluminum to metallic pigments of bismuth is 2:1-15:1, preferably 1:4:1-10, based on the respective metallic element; (2) hot molding comprising initially coating a semi-finished product made of steel by the above mentioned method and subsequently hot molding at a hot molding temperature of at least 800[deg] C; and (3) a hot molded steel component, which exhibits a siliceous coating in a total layer thickness of 1-10 mm on its surface, where the silicate coating comprises metallic phases of aluminum and bismuth obtained in the hot molding method. |
