Die steel with low carbide coarsening degree and low residual stress and preparation method thereof

• Main Authors: QU XIUJUAN, SUI YI, TIAN YONGJIU, FANG ENJUN, TIAN BIN, FENG DANZHU
• Format: Patent
• Language: Chinese; English
• Published: 22.08.2023
• 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

A steel plate comprises the following components in percentage by weight: 0.32 to 0.42 percent of C, 1.10 to 1.30 percent of Si, 1.10 to 1.30 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 3.0 to 3.4 percent of Cr, 3.3 to 3.5 percent of Mo, 1.10 to 1.40 percent of V, 0.80 to 1.00 percent of Co, 0.11 to 0.14 percent of Sn, 0.05 to 0.15 percent of Ba, 0.10 to 0.20 percent of Zn, 3.5 to 4.2 percent of Mo/Co, 0.20 to 0.30 percent of Ba + Zn, 1.8 to 2.2 percent of (Ba + Zn)/Sn and the balance of Fe and inevitable impurities. The production method of the steel plate comprises the steps of smelting, continuous casting, slab heating, rolling, straightening, slow cooling, quenching, circulating subzero treatment and tempering. After the die steel is subjected to heat preservation for 40 h at the temperature of 580 DEG C, the average size of carbides in a structure is increased by 4.9-5.1 nm compared with the average size of carbides in a final-state structure, the lo