CP steels characterize the transformation of steels that have very high ultimate tensile strengths. The ferrite/bainite matrix in the microstructure of CP steels consists of pearlite and retained austenite with martensite in small quantities. Retarded recrystallization or precipitation of microalloying elements such as Nb or Ti creates a very high grain refinement. The grain structure for the CP 800/1000 hot rolled steel is illustrated in Figure 1.
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Figure 1. Photomicrograph of CP 800/1000 hot rolled steel
Key Characteristics of CP Steels
The yield strength of CP steels is much higher than DP steels at equal tensile strengths of 800 MPa. Good hole expansion, high residual deformation capacity, and high energy absorption are the key characteristics of CP steels. The tensile strength-elongation graph of CP steels is depicted in Figure 2.
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Figure 2. The tensile strength-elongation graph of CP steels
The following table lists current production grades of CP steels and corresponding example automotive applications:
| |
|
| CP 500/800 |
|
| CP 600/900 |
|
| CP 680/780 |
Frame rails, chassis components, transverse beams |
| CP 750/900 |
B-pillar reinforcements, tunnel stiffener |
| CP 800/1000 |
Rear suspension brackets, fender beam |
| CP 850/1180 |
|
| CP1000/1200 |
Rear frame rail reinforcements, rocker outer |
| CP1050/1470 |
Rocker panels, bumper beams |
Download the Advanced High-Strength Steels Applications Guidelines free here, to learn more about the metallurgy, forming and joining of these new steels.
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This information has been sourced, reviewed and adapted from materials provided by WorldAutoSteel (World Auto Steel).
For more information on this source, please visit WorldAutoSteel (World Auto Steel).