Course Contents Commercial methods for the production of metal powders, powder characterization and testing, powder conditioning and function of addition agents. Consolidation of metal powders, i.e. Pressing, Cold Isostatic Compacting, Hot Isostatic Compacting, Powder Rolling, Powder Forging, Powder Extrusion, Powder Injection Molding, and Spray Forming. Theory of Sintering, Sintering Practice, Sintering Atmospheres, Sintering Furnaces. Powder Metallurgy of Refractory and Reactive Metals, Powder Metallurgy of Supper Alloys, Dispersion-Strengthened Materials. Secondary operation performed on P/M parts and products. Inspection and Quality Control for P/M Materials. The economics of P/M Production.
Definition of Powder MetallurgyPowder metallurgy may defined as, “the art and science of producing metal powders and utilizing them to make serviceable objects.” ORIt may also be defined as “material processing technique used to consolidate particulate matter i.e. powders both metal and/or non-metals.”
Importance of P/M:The methods of powder metallurgy have permitted the attainment of compositions and properties not possible by the conventional methods of melting and casting.Powder metallurgy is an alternative, economically viable mass production method for structural components to very close tolerance.Powder metallurgy techniques produce some parts which can’t be made by any other method.
The process of P/M is the process of producing metallic parts from metallic powders of a single metal, of several metals or of a combination of metals and non-metals by applying pressure. The powders are mixed mechanically, compacted into a particular shape and then heated at elevated temperature below the melting point of the main constituent.
Process of Powder Metallurgy: The process of P/M in general consists of a series ofsteps/stages to form a final shape. These stages are shown by asimple flow sheet diagram. Powder Production Powder Characterization & testing Mixing - Blending Processing - Compacting Sintering Operation Finishing Operations Finished P/M Parts
* Powder Metallurgy (P/M) is an improved alternativemethod as compared to Industrial Metallurgy (I/M) beingmore economical for large production series withprecision of design and savings of energy, material andlabor. Further it is a unique method for producing cermets,cutting tools, nuclear fuel elements, self- lubricating,copper-graphite brushes etc.
Advantages of P/M for Structural Components:These may be classified into two main headings;(a) Cost advantages, and(b) Advantages due to particular properties of sintered components.Cost Advantages:(i) Zero or minimal scrap;(ii) Avoiding high machining cost in mass production as irregularly shaped holes, flats, splines, counter bores, involute gear teeth, key-ways can be molded into the components;(iii) Extremely good surface finish at very low additional cost after sizing and coining;(iv) very close tolerance without a machining operation;(v) Assembly of two or more parts (by I/M) can be made in one piece;(vi) Separate parts can be combined before sintering.
RefrencesFundamentals of powder metallurgy by W. D. JonesPowder Metallurgy: Principles and Applications by F. V. LenelFundamentals of P/M by I. H. Khan