Microstructural variations at different distance from the surface in forged 18 Ni C300 maraging steel

Abstract

Microstructure and microtexture of forged 18 Ni C300 maraging steel at different solution annealed temperatures were studied to show strain distribution associated with forged surface distance. Samples were examined by Electron Back-Scattered Diffraction to characterize the microstructural parameters such as grain sizes, grain orientation and boundary characteristics throughout the forged samples at the surface, quarter depth and centre areas. The results showed a grain refinement across the forging depth, without changing its hardness. In addition, the textural variation was highly dependent on the value of local strain during forging processing. A high number of grains oriented along {001} planes parallel to forging direction (FD) were formed close to the forged surface. While, {110}//FD and {111}//FD texture fibres developed significantly by increasing the distance of forged surface. Keywords: Strain distribution, Maraging steel, EBSD, Grain orientation