Prediction of density in powder metallurgy parts by digital radiography

During mass production in powder metallurgy (PM), prediction of density is one of the most important factors for creation of cracks and flaws. Many factors can affect density such as shape and size of the part, particle size a shape of powder, its compressibility and so on. The measurement of density is necessary because it changes influence mechanical strength, hardness, electrical conductivity, and magnetic and gas permeability of PM compacts. The existing methods such as hydrostatic weighing and microscopic examinations are used for measuring density and these methods cannot be employed for direct density measurements in the special region of interested (ROI) of parts. Recently, a new method based on radiography has developed. This paper presents a method for prediction of density of powder metallurgy compacts using digital radiography. For this purpose, various density levels of powder metallurgy compacts were performed and radiography experiments were carried out on samples. The mean of interested ROI was measured for each sample from radiography image. The obtained mean vs. the density of the compacts was plotted and a mathematical relationship was derived between the mean of ROI and density. Comparison of experimental data from hydrostatic weighing experiments and obtained mathematical relationship for an unknown sample reveals a low discrepancy.

Keywords:

Powder metallurgy , Digital industrial radiography , Density measurement