Performance of Hot Stamping High Strength Steel (HSS) Technology
Hot stamping process should be optimized systematically, to produce premium quality vehicle components.
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Performance of Hot Stamping High Strength Steel (HSS) Technology
Hot stamping process should be optimized systematically, to produce premium quality vehicle components. Three major areas need to be addressed: (1) Understanding the theory and law of phase transformation in hot stamping process, capable of analyzing the phase transformation with the help of CCT (Continuous Cooling Transformation) curves. (2) Grasping producing process and specifying the influence of different factors, such as heating temperature, soaking time, cooling rate, etc. (3) Identifying the material performance indicators of the hot stamped steel, including strength, hardness, springback, uniformity, toughness, etc. and understanding the influencing factors of each performance indicators and their influence to the final hot stamping products. In this chapter, on the basis of fundamental theory and law of phase transformation, major factors in hot stamping process will be optimized, and optimal design has been conducted in order to optimize the producing process [14, 21, 42, 57, 58].
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Process and Principle of Hot Stamping HSS Hot Stamping Plate
Major steel suppliers all over the world have come up with a series of light-weight projects involving ultra-light body (ULSAB), ultra-light cover (ULSAC), and lightweight concept car project (USSAB-AVC) [24], which are mainly proposed to develop lower cost materials with more competitive potentials. In recent years, the demand of HSS with yield strength over 1000 MPa has increased dramatically in automobile industry. Figure 3.1 shows the differences in mechanical properties between common steel and hot stamping HSS where HSS is categorized as Ultra-High Strength Steel, with apparent advantages compared to other types of steel.
© Science Press and Springer Science+Business Media Singapore 2017 P. Hu et al., Hot Stamping Advanced Manufacturing Technology of Lightweight Car Body, DOI 10.1007/978-981-10-2401-6_3
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3 Performance of Hot Stamping High Strength Steel (HSS) Technology
Fig. 3.1 Classification map of mechanical property for automotive steel
Hot stamping steel can be generally classified in two types: with the protection of antioxidation coat and the other without the protection coat. Currently, in market, one of the widely used hot stamping steel is USIBOR1500 and its improved heir with Al–Si coat from Arcelor in Europe. Thickness of this product varies from 0.7 to 2.4 mm. Other companies and researchers [12, 18, 28, 40], however, restricted by intellectual property law, have to target on steel with galvanized coat, zinc-alloy coat, zinc–10Ni coat, etc. To this day, some new techniques aiming at antioxidation in hot stamping have been put in application in the production process. Besides the coated steel, steel without protection coat is also used in large quantity. SSAB, a Swedish company, has developed and manufactured hot rolling quenchable steel named as Domex including 22MnB5, 24MnB5, 26MnB5, 27MnCrB5, 30MnB5, 33MnCrB5, 38MnB5, which belongs to the same type with BTR ser
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