Sheet-billet produced hot-rolled pickled steel with thickness of 1.8mm or lower for automobile and production method thereof

Abstract

The invention relates to a sheet-billet produced hot-rolled pickled steel with thickness of 1.8mm or lower for an automobile, which comprises the following chemical components by weight: 0.04-0.07% of C, 0.10-0.30% of Si, 0.60-1.30% of Mn, 0.025% of P or less, 0.012% of S, 0.02-0.04% of Ti and 0.010-0.030% of Als. The preparation method of the sheet-billet produced hot-rolled pickled steel with thickness of 1.8mm or lower comprises the following steps: desulphurizing molten iron, smelting by a converter, alloying, treating by a ladle furnace, casting and rolling continuously, dephosphorizing high-pressure water by controlling the pressure at 25-35Mpa, controlling rolling, cooling by laminar flow, curling, pickling by acid, levelling by controlling the extension rate at 2% or lower, and finishing by adopting static oil removal. The produced thin hot-rolled pickled steel for the automobile, which has the tensile strength of 400MPa or higher and the thickness of 1.8 mm or lower, has the characteristics of low yield ratio, high surface quality, short production cycle and low cost, achieve the match of high strength and good stamping performance and can replace the cold-rolled high-strength steel to manufacture the automobile.

Description

technical field [0001] The invention relates to steel for automobiles, in particular to a hot-rolled pickled steel for automobiles with a thickness of ≤1.8mm and a tensile strength of ≥400MPa and a production method thereof. Background technique [0002] Hot-rolled pickled steel refers to the steel plate (coil) obtained by using hot-rolled materials as raw materials to remove the surface oxide scale by pickling, and after trimming, smoothing and oiling. It has the following characteristics: [0003] 1. Cost reduction, replacing cold-rolled sheets with pickled sheets can save costs for enterprises. 2. The surface quality is good. Compared with ordinary hot-rolled sheets, hot-rolled pickled sheets have removed surface oxide scale, improved the surface quality of steel, and are convenient for welding, oiling and painting. 3. High dimensional accuracy and good plate shape. After smoothing and finishing, the width and thickness accuracy are greatly improved, and the plate sh...

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Problems solved by technology

[0006] Aiming at the disadvantages of the current thin-gauge automotive structural steel with a tensile strength ≥ 400Mpa, which are mainly cold-rolled plates, the process is long and the cost is high, the invention develops a steel sheet with a thickness ≤ 1.8 under the condition of a tensile strength ≥ 400Mpa. mm, the yield strength ratio is not more than 0.8, and the steel plate has excellent stamping performance and good surface quality, which can replace high-strength cold-rolled plates and be used in hot-rolled pickled steel for automotive structures such as side beams and various reinforcement plates for passenger cars and other parts. its production method

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