High-strength economical X70 pipeline steel hot-rolling flat plate and production method thereof

• Main Authors: XU XIANGYANG, SUI YI, LIU WENYUE, HUANG SONG, REN YI, ZHANG LULIN, ZHANG SHUAI, LI YUN, WANG SHUANG, CHEN JUNPING
• Format: Patent
• Language: Chinese; English
• Published: 08.12.2010
• 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; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The invention provides a high-strength economical X70 pipeline steel hot-rolling flat plate and a production method thereof. The high-strength economical X70 pipeline steel hot-rolling flat plate comprises the following chemical components: 0.02-0.08 percent of C, 0.10-0.35 percent of Si, 1.40-1.70 percent of Mn, not more than 0.020 percent of P, not more than 0.005 percent of S, 0.04-0.07 percent of Nb, 0.008-0.030 percent of Ti, 0.02-0.045 percent of Als and the balance of Fe and unavoidable impurities. The production method comprises the steps of smelting, continuous casting and hot rolling and is characterized in that the heating temperature of a hot-rolling plate blank is 1,160-1,280 DEG C; the rough rolling temperature is 1,010-1,150 DEG C, and the finish rolling temperature is 830-950 DEG C; after the plate blank is rolled, the plate blank is subjected to control cooling; the final cooling temperature is 300-600 DEG C, the cooling speed is controlled to be 15-30 DEG C/S, and then the plate is air-coole