The transverse properties were inferior to the longitudinal properties for the existence of banded structure in 20G steel. In order to eliminate the banded structure and improve the transverse performance of 20G steel, different heat treatment processes were adopted. The results showed that conventional normalizing could reduce the banded structure and refine the grain sizes. When 20G was heated with 10°C/min heating rated and then held at 920°C for 2h, the banded structure in the steel was almost eliminated and the microstructure was homogeneous with fine grain size, the strength increased by 14%. The non-metallic inclusion and carbide in the microstructure leaded to stress concentration and separation with the base metal. To some extent, heat treatment can improve the distribution and form of non-metallic inclusions.

The project duration risk analysis has become more and more important with project management raised the duration requirement. Most of the existing analysis methods lack the linkage analysis of cost risk, aimed at this disadvantage, this paper proposes a new analysis method to project duration risk based on earned value measurement, discusses the different possible risk types under different earned value indexes, then divides the severity of duration risk into five different levels which will be convenient for project managers to take measures. Furthermore, an example is given behind in detail expressly illustrated the analysis process.