PROCESS FOR MANUFACTURING COIL-BREAK-FREE HOT STRIP AND AGE-RESISTANT HOT-GALVANIZED COLD STRIP

摘要

Process for manufacturing coil-break-free hot strip and age-resistant hot-galvanized strip with constant long-term elongation at yield and low yield point. Conventionally, coil breaks in hot strip are prevented either by adequate alloying or by dressing the hot strip to prevent elongation at yield. The steel strip of the invention, on the other hand, is manufactured with a minimal quantity of alloying titanium and a low reel temperature between 550 and 400°C. The quantity of alloying titanium chosen is equal to the quantity stoichiometrically necessary to bind the nitrogen but less than that required to bind the carbon and the nitrogen. In addition, the coil-break-free, age-resistant steel used for the hot-galvanized strips is a vacuum steel with a titanium content of 0.02 to 0.04 % or an LD steel with a titanium content of 0.03 to 0.08 %.