High-toughness low-yield-ratio longitudinal variable-thickness weather-resistant bridge steel and manufacturing method thereof

• Main Authors: LI XINLING, ZHANG TAO, LI JINGNIAN, ZHANG ZHE, YANG YING, JI WENBO, WANG YUBO, HAYASHIDA KO, CONG JINGONG
• Format: Patent
• Language: Chinese; English
• Published: 15.09.2023
• 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; 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 high-toughness low-yield-ratio longitudinal variable-thickness weather-resistant bridge steel and a manufacturing method thereof. The steel comprises the following components in percentage by weight: 0.05%-0.08% of C, 0.20%-0.40% of Si, 1.00%-1.30% of Mn, less than or equal to 0.010% of P, less than or equal to 0.003% of S, 0.04%-0.06% of Nb, 0.30%-0.45% of Ni, 0.10%-0.30% of Cu, 0.05%-0.15% of Mo, 0.40%-0.60% of Cr, 0.004%-0.015% of Ti, 0.01%-0.04% of Al and the balance of iron and inevitable impurities. The manufacturing method comprises the steps of smelting, continuous casting, heating, rolling, cooling and straightening. The steel plate produced by the method is uniform in same-plate performance: the same plate is thin, the thickness end strength difference is less than or equal to 15MPa, the percentage elongation after fracture is less than or equal to 3%, the yield ratio difference is less than or equal to 0.02, the impact energy difference is less than or equal to 30J, and the s