Production method of hub steel with ultrahigh strength and high hole expansion rate

Abstract

The invention discloses a production method of hub steel with ultrahigh strength and high hole expansion rate. The hub steel comprises the following components in percentage by mass: 0.040-0.055 wt% of [C], 1.30-1.40 wt% of [Mn], 0.010-0.020 wt% of [P], 0.010-0.020 wt% of [S], 0.010-0.020 wt% of [P] The steel comprises the following components in percentage by weight: less than or equal to 0.10 wt% of Si, less than or equal to 0.012 wt% of P, less than or equal to 0.004 wt% of S, 0.025-0.050 wt% of Al, less than or equal to 0.0050 wt% of N, 0.012-0.020 wt% of Nb, less than or equal to 0.050 wt% of Ti, less than 0.005 wt% of Ca and the balance of iron and inevitable impurities. The production process comprises the steps of molten iron pretreatment, converter smelting, LF refining, slab continuous casting and strip steel hot continuous rolling, and the thickness of a produced steel strip or steel plate is 2.5 mm-5 mm of the automobile hub steel. All performances of the ultrahigh-strength automobile hub steel produced by the method meet user requirements (the thickness of a steel plate is mainly 3.5 mm), the ultrahigh-strength automobile hub steel has the advantages of low cost and high cost performance, and the cost of a ton of steel alloy is lower than that of strip steel with the same strength level by more than 110 yuan.

Description

technical field [0001] The invention relates to a production method of an ultra-high-strength and high-hole-expanding-rate hub steel, which belongs to the field of iron and steel smelting and material processing. Background technique [0002] The wheel is an important part of the car, its structure, performance and weight directly affect the technical performance of the vehicle. In the field of automobile hub steel, increasing the strength of materials, reducing the weight of the wheel, and reducing the fuel consumption of automobiles represent the development direction of automobile hub steel. [0003] The tensile strength of the high-strength automobile wheel steel currently used is 440 MPa. Due to the low strength, the thickness of the steel plate used to manufacture the wheel increases accordingly, which increases the weight of the automobile, which is not conducive to the low-carbon and green development of the automobile industry. Therefore, in order to reduce the sel...

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Problems solved by technology

Due to the high yield strength of the material, the yield strength ratio is relatively high, which is not conducive to deep drawing forming such as hole expansion

[0009] (3) Patent application number ZL 200710093966.4, which discloses a "hot-rolled high-hole expansion steel plate with a tensile strength of 440MPa and its manufacturing method", the composition of which is: C: 0.01-0.0.06wt%, Si: 0-0.60 wt%, Mn: 0.80~1.30wt%, P: ≤0.035wt%, S: ≤0.010wt%, Nb: 0~0.25wt%, Al: 0.025~0.060wt%, N: ≤0.0060wt%, Ti: ≤0.03wt%, Ca: <0.005wt%, and the rest are iron and unavoidable impurities. The steel plate with a tensile strength of 440 MPa and high hole expansion rate is produced, but the strength of the material is low, which restricts the reduction of steel consumption. Can not achieve the purpose of reducing the weight of the car

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