| Abstract: | The microstructure characteristics and precipitation behavior of automobile beam steels produced by Compact Strip Production (CSP) were investigated by use of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy. The result shows that the final microstructure is mainly of polygonal ferrite and small amount of pearlite, the average ferrite grain size is about 3～6μm. Small amount addition Ti to aluminium-killed steel can help to refine the microstructure and improve the mechanical properties. A large number of fine precipitates have been observed in automobile beam steels. The mean particle size is about 10～30nm. Remarkable strengthening and grain refinement can be obtained by these nano-particles. |
