Columbium treated low carbon steel

Abstract

Abstract A PROCESS OF PRODUCING NON-AGING, LOW CARBON STEEL HAVING SUBSTANTIALLY NO YIELD POINT ELONGATION IN THE ANNEALED CONDITION AND FREEDOM FROM CIRITCAL GRAIN GROWTH. A MOLTEN STEEL HAVING AN ANALYSIS TYPICAL OF STEEL INTENDED FOR RIMMED OR KILLED DRAWING STEEL IS VACUUM DEGASSED TO DECARBURIZE TO A MAXIMUM CARBON CONTENT OF ABOUT 0.015%, AND COLUMBIUM (NIOBIUM) IS ADDED IN AN AMOUNT AT LEAST SUFFICIENT TO COMBINE WITH THE CARBON PRESENT IN THE STEEL. THE CAST MATERIAL IS HOT ROLLED, FINISHING AT 1500*-1700*F. (ABOUT 1090*-1200*K.) AND COILED AT A TEMPERATURE OF ABOUT 1500*F. (ABOUT 1090* K.) OR LESS. THE COLUMBIUM ADDITION RETARDS THE RATE OF RECRYSTALLIZATION OF THE COLD ROLLED PRODUCT, AND A WIDE SPECTRUM OF MECHANICAL PROPERTIES CAN BE OBTAINED IN THE FINAL PRODUCT BY CONTROL OF THE FINAL ANNEALING TIME AND TEMPERATURE WITHIN THE RANGE OF 1000* TO 1700*F. (ABOUT 810* TO 1200*K.). A PREFERRED PRODUCT IS COLD ROLLED AND ANNEALED STRIP SUITABLE FOR DEEP DRAWING, PORCELAIN ENAMELING, HOT DIP METALLIC COATING AND THE LIKE, CONTAINING AT LEAST ABOUT 0.025* UNCOMBINED COLUMBIUM AT THE HOT ROLLING STAGE, AS DETERMINED BY ANALYSIS AT ROOM TEMPERATURE, WHICH HAS AN AVERAGE PLASTIC STRAIN RATIO OF AT LEAST 1.8, AND A UNIFORM GRAIN SIZE BETWEEN ASTM 8 AND 10.

Inventors

• 👤 J Elias
• 👤 R Hook

Bibliographic Details