Counted if the grid intersection falls cleanly inside the target phase.
= The total number of grid points used per single field (e.g., 25 or 100). Step-by-Step Laboratory Workflow
The operator moves across a pre-determined number of fields (typically a minimum of 20 to 30 fields to control statistical error). For each field, points are tabulated using strict criteria:
While automatic image analysis is common, ASTM E562 remains critical in several scenarios.
) is determined. The estimated volume fraction is calculated as:
However, accuracy depends on the user following the standard's procedures. Key practical tips from experienced metallographers include:
For each field, compute:
Awarded if the grid intersection falls directly on the phase boundary (interfacial line).