Method for manufacturing 460Mpa high-toughness medium plate for bridge

Abstract

The invention relates to a production method for medium plates used in bridges with the high strength and toughness of 460Mpa and belongs to the technical field of bridge steels. The smelting production technique with the carbon content of 0.07 percent to 0.10 percent is used, and the carbon content is less than or equal to 0.040 percent by the converter endpoint; and the carbon adding is controlled by using silicon ferromanganese iron and micro-carbon ferromanganese to be matched with manganese, desulfurizating the large argon with the opening of 100 percent and heating the argon with the opening of 30 percent; the micro-alloying of Nb, V and Ti is used; the micro-alloying is treated in vacuum after being refined in a ladle furnace; the sheet slab constant casting speed casting technique guarantees the casting blank quality; two stages of control rolling are carried out on a heavy plate mill, and the rerolling temperature is 850 DEG C to 950 DEG C, and the finish rolling temperature is 790 DEG C to 810 DEG C; a rolled control cooling system with the finish cooling temperature of 630 DEG C plus or minus 20 DEG C and the cooling temperature of 10 to 15 DEG C / S is used for obtaining ferrite and pearlite tissues; the yield strength of the steel plate is more than or equal to 460Mpa, the toughness under the low temperature of minus 40DEG C is more than or equal to 100J. The production method for the medium plates has the advantages that the tissue, the property and the welding adaptability of the steel plates can be controlled stably and a trail is blazed in the technical route of producing the bridge steel plates with the high strength and toughness of 460Mpa.

Description

technical field [0001] The invention belongs to the technical field of steel for bridges, and in particular relates to a method for producing medium-thick steel plates with high strength and toughness of 460Mpa for bridges, which is suitable for the production of medium-thick steel plates with high strength and toughness (hereinafter referred to as Q460qE) for bridges with a yield strength of 460Mpa. Background technique [0002] Bridge slabs are important raw materials for manufacturing bridges and other engineering structural parts. With the development of modern steel structure bridges to the high-parameter direction of long-span bolted or fully welded structures, the development of high-strength, high-toughness, and easy-to-weld bridge steel has become An important topic with a high technical content. The traditional production process of medium and thick plates for bridges at home and abroad is basically based on 16Mnq (about 0.15% carbon), and the mechanical properties...

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Problems solved by technology

The traditional production process of medium and thick plates for bridges at home and abroad is basically based on 16Mnq (about 0.15% carbon), and the mechanical properties are improved by adding microalloys. This type of steel plate has poor toughness and welding adaptability; low carbon bainite steel Good performance, but due to the addition of precious alloying elements such as Mo and Cu, the smelting of low carbon steel (C≤0.06%) is uneconomical, the structure control is difficult, and the production cost is high

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