TABLE OF CONTENTS The powder metallurgy processes are more competitive than other fabrication methods for numerous materials and finished parts, in part due to their high flexibility regarding the manufacturing processes involved. PM offers chances for manufacturing of materials than cannot be obtained by classical metallurgical techniques, such as cemented carbides or very high alloy tool steels with an isotropic microstructure. In production of structural parts, PM offers higher precision, eliminating most of the machining operations required for castings and wrought semi-products. It is thus more cost effective and environmentally friendly, resulting in high material utilization. Figure 2.1 shows the basic steps of the powder metallugy process as used for manufacturing of structural parts and semi-finished products which may be subjected to supplementary machining. Each of these main steps contains some particularities and introduces specific physical, chemical and technological factors that affect the processing and final properties of a sintered material and by this also of each structural component.
At present, there are two main methods for production of iron and steel powders. Together, the production of sponge iron powders by reduction of iron oxides and by water atomisation of iron and of low alloyed steel powders accounts for more than 90% of iron and steel powders produced around the world. (The production of powders by gas atomisation is limited to high alloy and some special powders). The main physical, chemical and technological properties of these two groups of iron-based...
