Band Slope Research Articles

Damage evaluation of the austenitic heat-resistance steel subjected to creep by using Kikuchi pattern parameters

Abstract Austenitic heat-resistance steel is widely employed in ultra-supercritical power generation because of its superior performance. This article reports the evaluation of creep damage of a typical Super304H austenitic heat-resistance steel by using the Kikuchi pattern parameters, such as band contrast (BC), mean angular deviation (MAD), and band slope (BS). It was found that the mean BC and MAD values did not show a monotonic changing trend and then an in-depth research that distinguished grain boundary and grain interior regions of Super304H steel was studied, respectively. The results manifested that, with the increase of creep time, both the mean BC and BS values showed a monotonic decreasing trend, while the MAD did not. Besides, compared with the BC, the change amplitude of BS was larger. The results indicate that the BS could be a useful indicator, which can be utilized to evaluate the creep degree of Super304H steel in a quantitative way.

Phase Analysis on Dual-Phase Steel Using Band Slope of Electron Backscatter Diffraction Pattern

A quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite-martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger phase contrast than another conventional one, band contrast. Owing to high sensitivity to lattice defect and little orientation dependence, BS provided handiness in finding a threshold for phase discrimination. Its grain average gave a superior result on the discrimination and volume fraction measurement of the constituent phases in the DP steel.