Research and Development of Hot Rolled Strip Steels for Automotive Frame Application.pdf

Research and Development of Hot Rolled Strip Steels for Automotive Frame Application HUANG Xiao-hu (Hot Strip Mill ,Taiyuan Iron Steel (Group) Co., Ltd., 030003) Abstract: The article introduces the designing of chemical composition, the optimizing on production process as well as the properties of T420L and T510L, a series of hot rolled strip for automobile beam. It has been proved in practice that T420L and T510L have good integrated mechanical properties, especially excellent cold formability. They have become a new type of material, which are much more ideal for automobile frame in home market currently. Key words: automobile beam steel, micro-alloying, property 1 Preface Automobile beam is the main part of auto truck, car, cross country car and bus. It can affect the lifetime of the car and the security during riding. Therefore, as material for automobile beam, it has very strict requirements to the quality of the hot rolled strip, not only the quality of surface, the dimension tolerance and special requirement to the flatness, but also excellent integrated mechanical properties, such as high strength with enough toughness, good ability of antifatigue, deep formability and weldability with little anisotropy. Based on the quality requirements above mentioned and took the less weight of the car and higher security of riding into consideration, most hot rolled strip for automobile beam in current home and abroad markets are low alloy high strength steel with chemical elements of Mn, Si, Cr, V, Ti, Nb and some of rare earth elements. TISCO started the development of hot rolled strip for automobile beam in 1996. At the time, the major two steel grades were 16MnL and 10TiL. However, due to the limited characteristics of steel grades, the condition of machinery and process, some quality problems existed during the course of development, such as difficulty in controlling the chemical composition, the large variation of stren