Production method of X70 hot-rolled medium plate for submerged pipeline

• Main Authors: XU XIAODONG, LI SHAOPO, ZHA CHUNHE, WANG WENJUN, LI ZHANJUN, LIU JINGANG, LI QUN, LI JIADING, MA QINGSHEN, ZHANG GUODONG, DING WENHUA, JIANG ZHONGXING, BAI XUEJUN
• Format: Patent
• Language: Chinese; English
• Published: 21.11.2012
• 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 production method of an X70 hot-rolled medium plate for a submerged pipeline. The medium plate comprises the following components in percentage by weight: 0.035 to 0.07 percent of C, 0.10 to 0.35 percent of Si, 1.40 to 1.85 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.0035 percent of S, 0.01 to 0.06 percent of Alt, 0.035 to 0.07 percentof Nb, 0.008 to 0.020 percent of Ti, 0.10 to 0.30 percent of Mo, 0.10 to 0.25 percent of Ni, 0.10 to 0.25 percent of Cr, 0.10 to 0.25 percent of Cu and the balance of Fe and inevitable impurity elements. In the steel plate manufacturing process, the effects of the alloy elements and the potential of an excavation thermo-mechanical control process are fully exerted through an optimized blank type design, a strict heating schedule and a reinforced thermo-mechanical control process in coordination with an appropriate amount of Ni, Cr and Cu alloy elements, so that an organization form based on auniform fine acicular ferr