Hot rolled wheel rim steel plate with tensile strength of 550MPa grade and manufacturing method thereof

Abstract

The invention provides hot rolled wheel rim steel with tensile strength of 550MPa grade and a manufacturing method thereof. The wheel rim steel comprises the following chemical compositions in percentage by mass: 0.02 to 0.07 percent of C, 0 to 0.3 percent of Si, 0.8 to 1.2 percent of Mn, less than or equal to 0.035 percent of P, less than or equal to 0.005 percent of S, 0.025 to 0.060 percent ofAl, less than or equal to 0.0060 percent of N, 0 to 0.10 percent of Nb, and the balance of Fe and inevitable impurities. In the manufacturing method, the billet heating temperature is between 1,150 and 1,250 DEG C, the rolling deformation is over 80 percent; and the finish rolling temperature is between 830 and 900 DEG C, and the steel plate after finish rolling is cooled to be between 560 and 660 DEG C at a speed of between 20 and 80 DEG C / second for reeling, and is air-cooled to room temperature. While losing weight, the steel can still maintain excellent welding performance; and the methodis simple and convenient to operate, and saves production cost.

Description

technical field [0001] The invention relates to a wheel rim steel, in particular to a wheel rim steel plate with excellent tensile strength. Background technique [0002] In recent years, people's awareness of environmental protection has been increasing day by day, reducing the fuel consumption of cars and reducing CO 2 emissions has become a global voice. Among the various measures to achieve this goal, automobile weight reduction is a very effective means. While reducing the weight of automobiles, higher requirements are put forward for automobile safety, which increases the demand for various advanced new steel materials with high strength and good processing performance. [0003] The car chassis, wheels, suspension and its surrounding parts are mainly made of hot-rolled steel plates, which account for more than 25% of the total weight of the car body. Since many of the components in these areas are relatively thick and heavy, there is a very large potential for weigh...

AI Technical Summary

Problems solved by technology

The common features of these types of hot-rolled high-strength plates are high C content (see Table 2), poor welding performance; low Nb content, and insufficient steel strength

[0006] At present, the thickness of high-strength rim steel is generally not greater than 6mm. After flash butt welding, multiple forming and flaring processes are required. The strength of ordinary SAPH carbon-manganese steel plates is often relatively low (≤300MPa). Increasing the content of C, Si, and Mn to increase the strength of the steel will increase the carbon equivalent of the steel and damage its welding performance, resulting in cracking of the welded part during forming and flaring, which cannot meet the technological requirements of automobile wheels

The existing rim steel production methods generally require heat treatment, and complex cooling processes are required after hot rolling, which are complex and costly