Coercivity Inspection of Tungsten Carbide

Coercivity is a key magnetic parameter closely related to WC grain size and overall material performance.

In WC–Co cemented carbides, coercivity provides an indirect and non-destructive method to monitor grain size, microstructure and batch consistency. At Langsun Carbide, coercivity measurement is an important part of our quality control system for tungsten carbide grades.

We use a dedicated coercivity meter designed for hardmetal testing:

The tungsten carbide sample is magnetised in a controlled magnetic field until it reaches a saturated state.

The applied magnetic field is gradually reduced toward zero while the sample’s magnetisation is monitored.

The field strength at which the magnetisation of the sample returns to zero is recorded as the coercive force (Hc).

For a given composition, coercivity is highly sensitive to WC grain size: finer grains generally give higher coercivity, while coarser grains result in lower values. This makes coercivity an effective indirect indicator of grain size distributions in production.

Coercivity directly reflects microstructural characteristics that strongly influence tungsten carbide performance:

● Grain size control — fine grains improve hardness and wear resistance, while coarser grains improve toughness; coercivity helps ensure the grain size is within the designed range.

● Process consistency — variations in coercivity can indicate non-optimised sintering temperature, holding time or cooling rate, even when bulk properties seem acceptable.

● Non-destructive monitoring — coercivity allows continuous monitoring of microstructure without damaging finished products.

By combining coercivity with hardness, density, magnetic saturation and metallography, we verify that each batch not only meets nominal specifications but also has the correct internal structure for reliable service.

Langsun Carbide uses coercivity as a powerful tool for microstructural quality assurance:

Each tungsten carbide grade has a target coercivity window associated with its designed WC grain size and performance profile.

Coercivity values are recorded for each production batch and correlated with metallographic observations.

If coercivity deviates from the specified range, we investigate immediately and adjust processing parameters to restore microstructural stability.

During new grade development, coercivity is used to fine-tune WC grain size and optimise the hardness–toughness balance.

Through systematic coercivity measurement, Langsun Carbide ensures that the microstructure of each tungsten carbide grade remains under strict control from batch to batch.