On the influence of reduction on the grain geometry in hot hydrostatic extruded brass samples
Warsaw University of Technology, Department of Materials Science and Engineering, Narbutta 85, 02-524 Warsaw, Poland
Polish Academy of Sciences, High Pressure Research Center - Unipress, Sokolowska 29/37, 01-142 Warsaw, Poland
Polish Academy of Sciences, High Pressure Research Center - Unipress, Sokolowska 29/37, 01-142 Warsaw, Poland
Abstract
Grain size and shape in commercial brass type 65/35 samples after hot hydrostatic extrusion have been studied. Samples have been extruded with different reduction ratios (defined as billet cross section area over produced wire cross section area) varying from 54 to 225. Cylindrical billet of 50 mm diameter heated to 800°C has been used for all reduction ratios. Studies of microstructure have been carried out by means of automatic image analyzer connected to light microscope on sections parallel to the axis of extruded wires. It has been found that with increasing reduction ratio the grain size decreases, especially in the range of smaller reductions. It has been also noticed, that shape of grain depends on the distance of the tested area from the surface of the sample. Distance from the surface has been found to have a bigger influence on the shape factor of grains than the reduction ratio. A brief proposition of interpretation of changes in shape factor with the distance from sample surface is given.