Application and future use of high strength steels
The steels mentioned previously are used widely in modern automobile bodies as illustrated below. Note the use of highest strength grades such as the boron steel and the CP 800 at the front and along the side-bars to provide energy absorption and to maintain the integrity of the passenger space during a collision.
Despite the large amount of work carried out already steel development continues to meet the demands of future vehicle designs
Using much higher alloy contents, principally carbon, manganese and aluminium, the microstructure can be made 100% austenite at room temperature. These TWIP steels have high strength, typically 1,000 MPa and excellent ductilities up to 60 %. They have not been widely adopted because of the high alloy cost and difficulty in steel making.
TWIP steels contain typically 20% Mn but work is being carried out to look at steels with up to 10% Mn with properties intermediate between fully austenitic TWIP steels and conventional ferrite- based steels.
To help with weight reduction attempts are also being made to develop steels with lower densities. This involves the use of significant additions of lighter elements such as aluminium.