GJV-500Si5 Graphite classification and fracture appearance in the tensile test

Vermicular graphite cast iron is standardised in DIN EN 16079:2013, the grades EN-GJV-300 to EN-GJV-450 are classified according to tensile strength. GJV-500Si5 is a non-standardised vermicular graphite cast iron whose high strength is achieved by a silicon content of approx. 5% (solid solution strengthening). In particular, the increased service life under thermal fatigue makes the material interesting for components with higher operating temperatures.

The fracture surface of the tensile specimen shows quasi-split fracture, i.e. predominantly split fracture with occasional tiny honeycomb fractures between the graphite “worms”. The matrix is purely ferritic. Tensile strength Rm = 544 MPa, Rp0.2 = 498 MPa, elongation at break A = 1.8%.

Graphite classification according to EN ISO 945-1:2019

• Graphite form III
• Guide number for the size range: 7 (approx. 90%), 4 (approx. 10%)