The cracking formation factors of steel 430F rolled bar are analyzed by scanning electron microscope

ultra- high temperature laser confocal microscope

Gleeble-3500 and other experimental equipment combined with professional image processing software

the modification effect and mechanism of each element and the high temperature mechanical properties. The results show that the control of MnS morphology in 430F steel is poor

and the tiny crack caused by long strip MnS is the main reason for cracking. Fine MnS ・ Al

2

O

3

• MgO is formed by magnesium modification and coarse MnS • (Te) is formed by tellurium modification to obviously improve the morphology of MnS

no cracks were found in the rolled products. The reduction of area of steel 430F changes obviously at high temperature

while the tensile stren

gth changes significantly at low temperature

therefore

with increasing the starting rolling temperature of unmodified steel from 1180 °C to 1 200 ~ 1210 P and reducing the final rolling temperature from 1000 °C to 970 ~ 980 °C

the yield of products can increases from 85% to 95%.