Effect of Powder Properties on the Compressibility of Water-Atomized Iron and Low-Alloyed Steel Grades

Paper in proceeding, 2013

Compaction of iron and steel water-atomized metal powders is a multiplex process. Lack of solid knowledge concerning the respective mechanisms governing the process and factors affecting them hinders its simulation. Solid solution strengthening is widely considered one of the most influential factors in compressibility, especially for prealloyed grades. Results indicate the significance of powder geometry, size distribution, morphology, etc., on the powder compressibility at different compaction stages. Compaction tests in the range of 50 to 800 MPa for four different size fractions for iron and Cr-Mo prealloyed powder grades are presented. The effect of the microstructure and internal inclusions was evaluated using HR-SEM combined with EDX and EBSD mapping. Experimental results enabled the quantification of the compaction behavior based on parameters associated to the geometrical and mechanical properties for each fraction. A two stage densification process was observed for both grades that includes initial particle rearrangement and subsequent bulk mechanical deformation.