Low yield ratio chromium-molybdenum steel plate and production method thereof

Abstract

The invention relates to a low yield ratio chromium-molybdenum steel plate and a production method thereof, belonging to the technical field of steel smelting. The production method comprises the following processes of smelting continuous casting, heating and rolling, and thermal treating. The steel plate comprises the following components by weight percent: more than or equal to 0.13% and less than or equal to 0.17% of C, more than or equal to 0.30% and less than or equal to 0.40% of Si, more than or equal to 0.50% and less than or equal to 0.70% of Mn, less than or equal to 0.007% of P, less than or equal to 0.005% of S, more than or equal to 1.00% and less than or equal to 1.10% of Cr, more than or equal to 0.50% and less than or equal to 0.65% of Mo, less than or equal to 0.20% of Cu, more than or equal to 0.10% and less than or equal to 0.20% of Ni, less than or equal to 0.003% of Sb, less than or equal to 0.010% of Sn, less than or equal to 0.010% of As, the balance of Fe and inevitable impurities. The low yield ratio chromium-molybdenum steel plate meets the requirement of domestic and aboard petrifaction and coalification industries on lowing the yield ratio of the chromium-molybdenum steel plate used at high temperature environment, can be widely used on devices such as delay coking devices of coke drums and hydrogenation reactor and the like, has good cold bending property, does not crack when being manufactured, and has good rebound elasticity and good plate shape.

Description

technical field [0001] The invention relates to a chromium-molybdenum steel plate with a low yield ratio and a production method thereof, belonging to the technical field of iron and steel smelting technology. Background technique [0002] In recent years, the development of petrochemical and coal chemical industries has increasingly required large-scale refining and chemical equipment, higher requirements for equipment safety, and more stringent requirements for the performance of steel plates used in equipment manufacturing, especially for low-temperature toughness. Increasingly demanding. At the same time, with the enlargement of equipment, the requirements for equipment to resist harsh and extreme environments are getting higher and higher. For chromium-molybdenum steel plates used in petrochemical and coal chemical industries, some design units have begun to include the yield ratio into the design specifications, and will become a trend. In the background technology, ...

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Problems solved by technology

In the background technology, the general normalized + tempered chromium molybdenum steel products have a yield ratio of 0.82~0.87. However, some existing design specifications have limited the yield ratio of the steel plate to less than 0.80, and the requirement is to meet the Simulating the post-weld state does not lose the low-temperature impact toughness of the steel plate; in order to reduce the yield ratio of the steel plate, the background technology needs to reduce the cooling rate of the steel plate after normalizing to meet the appropriate ferrite content in the structure, but this will inevitably affect the simulated post-weld impact toughness of the steel plate, and if you want to normalize in the two-phase zone, you must maintain a certain cooling rate, otherwise it will also damage the impact toughness of the steel plate

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