Ferrite Content by Point Count Method (Lab-based)

Duplex stainless steel is widely used in many areas, such as the chemical, food and oil & gas industries. They are characterized ideally by equal amounts of ferrite and austenite, which provides increased mechanical resistance due to the fine grain size. Due to their significant properties in mechanical and corrosion resistance, these materials are useful for industries requiring long-life components.

Mechanical properties and corrosion resistance depending on the steel’s ferrite content, especially at high temperatures. The ferrite content measurement provides critical data to prevent the steel’s future failure or damage. This ferrite content test is useful for industries such as oil and gas and power and process engineering plants exposed to high temperature, aggressive media and high pressure. In stainless steel, if the ferrite content is too low, the weldment is susceptible to hot-cracking or solidification cracks, and if the ferrite content is too high, the toughness, ductility, and corrosion resistance of the steel are reduced.

PTS forms ferrite content counting conforming to ASTM E562, which involves the sample preparation and etching of cross-sectional samples to be evaluated under a microscope for systematic point-based counting.

This test is usually used to evaluate the volume fraction of ferrite in duplex and austenitic stainless steels, especially for weldment products. If the volume fraction of ferrite is too low, the stainless steel may be susceptible to solidification cracking upon welding, and if the volume fraction is too high, the material may not possess enough corrosion resistance.