Manufacturing method of low alloy steel thick plate with surface-layer ultra-fine grain ferrite

• Main Authors: PAN TAO, SU HANG, WANG RUIZHEN, YANG CAIFU, CHAI FENG, SHI ZHONGRAN
• Format: Patent
• Language: Chinese; English
• Published: 17.05.2017
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The invention provides a manufacturing method of a low alloy steel thick plate with surface-layer ultra-fine grain ferrite, and belongs to the technical field of low alloy steel production. According to the control technical parameters, the manufacturing method comprises the technological steps that the reheating temperature of a plate blank processed before rolling ranges from 1050 DEG C to 1200 DEG C; in the rough rolling stage, the rolling temperature ranges from the austenite recrystallization final temperature Tnr DEG C to (Tnr+100) DEG C; accelerated cooling is conducted on the surface of an intermediate blank at the speed ranging from 6 DEG C/s to 33 DEG C/s so that the temperature of the surface of the intermediate blank can range from Ar3 to Ms, the rolling temperature of each pass of finish rolling ranges from (Ac1+40) DEG C to A3 DEG C, and the average strain rate of the passes ranges from 0.2s<-1> to 6s<-1>; and after rolling is finished, the steel plate is quickly cooled at the speed ranging from