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15.3 Material Description
Hot rolled BR1500 press harden steel is employed in the study. Its mechanical properties are significantly influenced by the temperature and strain rate. It would undergo a
phase transformation to austinite during heating process. The material has a Young’s
modulus about 210 GPa at room temperature and decreases along with the temperature increasing, dropping down to 120 GPa at 1000
◦ C. On the other hand, the flow
stress of the material is elevated by higher strain rate [15]. Determined flow stress of
the austenite between 600 and 900
◦ C at different strain rates are shown in Fig. 15.7.
Higher strain rate leads to a high flow stress.
Within this temperature window the BR1500 exhibits an excellent formability
as a consequence of the reduced flow stress at elevated temperatures. The in-die
Fig. 15.7 Material
properties of BR1500 of
different temperatures and
strain rates
0
200
400
600
800
1000
Young's modulus (GPa)
Temperature ( C)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0
200
400
600
25 C 0.1 /s
500 C 0.1 /s
600 C 0.1 /s
600 C 1 /s
900 C 0.1 /s
900 C 1 /s
True stress (MPa)
Plastic strain