Metallographic tests

Metallographic examination:

The examination of the microstructure of a component is usually carried out in order to verify that the quality heat treatment performed on that component reached the desired results, or it can be used to identify the plausible cause of failure of a component.

In order to properly examine the microstructure of a metallic material, the surface of the test piece is properly polished to a mirror like finish and suitably etched in order to reveal the desired features. Different types of etchant will produce different results and are properly selected depending on the structures or phases to be examined. Both the preparation of the specimen (ASTM E3) and the etching (ASTM E407) are regulated by international standard witch are thoroughly followed.

Hammer laboratory is equipped with all the necessary instruments to properly perform the preparation of the specimens and have two microscopes capable of performing analysis in bright field, dark field and with differential interference contrast (DIC) at magnification ranging from 25X up to 1000X.



Grain size evaluation:


The evaluation of average grain size is fundamental in the characterization of components because many of the properties of a material are correlated to the grain size. This test method can be used both for verifying the conformity of a component or to study and characterize a production process.


There are various techniques used to define the grain boundaries of a material, ranging from heat treatments to different etching techniques. International standards such as ISO 643 and ASTM E112 describe the most widely used techniques for the identification of grain boundaries and the evaluation of the average grain size.


Hammer laboratory uses advanced instrumentation and software in order to properly evaluate the grain size with different methods.



Determination of the inclusion content of steel:


The determination of the inclusion content of steel is a standard practice used to check for exogenous inclusion in steel products, it is used to verify the suitability of a material for various applications and can be used also in forensic engineering when determining the plausible cause of failure of a component.


To properly evaluate the inclusion content a discrete number of specimens have to be taken from the component, in order to evaluate the cleanliness throughout the whole component. Various standards describes the methods used to perform the count, the most commonly used are ASTM E45 and ISO 4967.


Hammer laboratory is equipped with an automatized microscope and a software that is capable of analyzing up to six specimens at a time, granting an accurate evaluation in a reduced time.



Other analysis:


Hammer laboratory is also equipped with the instrumentation required to perform
percentage of phase evaluation according to ASTM E562 and ASTM E1245, 
macroetching according to ASTM E340 and E381, determination of depth of carburization, determination of the thickness of coatings and other tests.


Our technicians are highly skilled and constantly improve their knowledge following
specific courses in order to maintain their competences up to date with the latest scientific improvements.