Method for manufacturing a high toughness steel without subjecting it to heat treatment

Abstract

Abstract A HIGH TOUGHNESS STEEL ESPECIALLY ADAPTED TO BE USED AS A MATERIAL FOR CONSTRUCTIONS TO BE USED AT LOW TEMPERATURES IS MANUFACTURED BY THE STEPS OF MAKING AN INGOT BY ADDING TO A FUNDAMENTAL STEEL HAVING A COMPOSITION OF FROM 0.03% TO 0.13% CRBON, 0.10% TO 0.60% SILICON, FROM 0.20% TO 2.00% MANAGANESE, UP TO 0.035% ALUMINIUM AND THE BALANCE BEING IRON AND IMPURITIES, AT LEAST ONE ELEMENT SELECTED FROM THE GROUP CONSISTING BY WEIGHT OF UP TO 0.2% NIOBIUM, UP TO 0.2% VANADIUM, UP TO 0.15% TITANIUM, UP TO 0.20% ZIRCONIUM AND UP TO 0.30% TANTALUM; ROUGH HOT ROLLING OR FORGING THE INGOT TO FORM A BILLET OR SLAB; THE BILLET OR SLAB BEING COOLED DURING SAID ROLLING OR FORGING TO BELOW THE A1 TRANSFORMATION POINT; UNIFORMLY REHEATING THE BILLET OR SLAB FROM BELOW THE AR1 TRANSFORMATION POINT AT ITS FINAL ROLLING OR FORGING STAGE TO A TEMPERATURE WITHIN 150*C. ABOVE THE AC3 TRANSFORMATION POINT; WORKING THE BILLET OR SLAB TO CAUSE A MORE THAN 10% THICKNESS REDUCTION, SAID WORKING BEING COMPLETED AT A TEMPERATURE IN THE VINCINITY OF THE AR3 TRANSFORMATION POINT; AND AIR COOLING OR FURNACE COOLING THE SLAB OR BILLET TO ROOM TEMPERATURE.

Inventors

• 👤 Katao Miyano
• 👤 Masahide Shimazaki

Bibliographic Details