Factors Affecting Tensile Properties of Castings

The basic data on the mechanical properties of a casting are frequently obtained from a tensile test, in which a suitable specimen machined from the casting is subjected to increasing axial load until it fractures. The engineering tension test is widely used by casting manufacturers as an acceptance test for customer specifications. However, tensile bars machined from castings often provide undesirable information, thereby leading one to question the part integrity.

This paper, therefore, discusses the various factors that affect tensile properties obtained from specimens machined from actual castings. These factors include:

1. 1
   Type of casting process
2. 2
   Wall thickness of castings
3. 3
   Microstructure
4. 4
   Size and distribution of inclusions in a tensile bar
5. 5
   Type and distribution of porosity in a tensile bar
6. 6
   Size and shape of tensile bar
7. 7
   Location of tensile bar in a casting

Results from this investigation indicate that achieving undesirable tensile properties do not necessarily indicate that a part would not perform its intended function satisfactorily.