Metallography is that branch of science which deals with the study of properties and structure of metals and alloys by making use of X-Ray Diffraction and other Microscopic Techniques. The main objective of carrying out metallographic tests is to examine the microstructure of any metal or an alloy sample. The three dimensional arrangement of the atomic elements ranging from 1pm to 1mm is examined by the means of Light Optical or Scanning Electron Microscope.
Some of the interesting features which are studied under microstructure are phase transformation, volume fractions, grain size, phases, grain boundaries, morphology, effective case depth, banding, non-metallic inclusions in steel, porosity, cross contamination and several others. The microstructures signify the mechanical properties such as corrosion resistance, toughness, strength, mechanical workability and ductility and influence their applications. The specimen preparation for carrying out metallographic testing is a very crucial step and Spectro has set a well devoted workshop for this purpose. The steps that needs to be followed for sample preparation are documentation, sectioning, cutting, mounting, planar grinding, rough polishing, final polishing, etching, microscopic analysis and hardness testing.
Significance of Metallographic studies:
It gives an idea about the composition of an alloy, like the amount of Carbon in Steel, % of Tin present in Bronze, etc.
It gives information about the annealing temperature, tempering and quenching ranges.
It signifies the type and extent of corrosion, internal and external both.
It provides details about the nature of surface coating.
It provides information about the manufacturing details of an object like soldering, welding, casting, etc.
Because a complete knowledge of microstructure of metals and alloys is required to understand and control their behavior thus, Spectro offers metallographic testing facilities which aids to quality assurance, failure analysis and also research and development.
Tests under Metallographic Testing:
Hardness Testing: Rockwell, Vicker, Knoop, Microhardness and Case depth.
Coating Testing: Adhesion, Bend test, Spot test, Weight test, Thickness test, pore count,
Metals Chemistry: Coating weight, Elemental analysis through ICP-OES, Density and Specific
Forming Evaluation: Vickers Hardness Test Bend test, Flare test, Coil test
Microstructure Evaluation:Rockwell Hardness Test SEM, Heat treatment, Weld evaluation, Grain size, Carburization
and Decarburization, Case depth, Casting discontinuous, Inclusion content, etc.
Corrosion Rate Testing
Tensile, Yield Stress/0.2% Proof Stress, Elongation, Reduction in area and Crushing Test