400-500Mpa grade high-uniform elongation hot rolled steel sheet and manufacturing method thereof

Abstract

The invention discloses a 400-500Mpa grade high-uniform elongationhot rolled steel sheet and a manufacturing method thereof. The 400-500Mpa grade high-uniform elongationhot rolled steel sheet is prepared from the following components in percentage by weight: 0.04-0.08 percent of C, 0-1.6 percent of Si, 0.8-1.5 percent of Mn, smaller than or equal to 0.035 percent of P, smaller than or equal to 0.001 percent of S, 0.025-0.060 percent of Al, smaller than or equal to 0.0060 percent of N, more than one of smaller than or equal to 0.03 percent of Ti, smaller than or equal to 0.05 percent of Nb andsmaller than or equal to 0.0050 percent of Ca and the balance of Fe and inevitable impurities. The steel sheet provided by the invention does not need to be subjected to heat treatment, is directly manufactured on a conventional hot rolling production line, is thin in specification (smaller than or equal to 12 mm), has the tensile strength being in a 400 Mpa grade or above and has the uniform elongation being the high uniform elongation of 20 percent or above; and after hot rolling, the steel sheet is relatively simple in cooling technology, uniform in performance and good in sheet shape, hasgood cold processing performance and welding performance, is low in production cost and can meet the requirements for formation performance of complex-shaped parts including an automotive chassis anda structural member.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a 400-500MPa-level high-uniform elongation hot-rolled steel plate and a manufacturing method thereof, without heat treatment, product thickness not exceeding 12mm, strength of 400-500MPa-level, high uniform elongation, This steel plate is especially suitable for use as a car chassis component. Background technique [0002] Steel plate is one of the most commonly used materials in automobiles. It is widely used in the manufacture of structural parts of automobiles and bears different loads in various positions of automobiles. [0003] Hot-rolled steel plates are mainly used for car chassis, wheels, suspension and their surrounding parts, and its weight accounts for more than 25% of the total weight of the car body. The 400-500MPa hot-rolled steel plate is the most widely used material in the strength range. It usually has very good formability and weldability, and can m...

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