Ferrite test is a fast, inexpensive, and accurate way to measure delta ferrite content in austenitic and duplex stainless steel. Ferrite testing can establish the ideal ferrite content balance between ductility, toughness, corrosion resistance, and crack prevention.
Ferrite testing can be deployed at chemical, energy and processing plants, where the fabricated steel is subject to heat, aggressive media and high pressure. Steel destined for these plants must therefore be highly corrosion- and acid–resistant, maintaining resilience even at high temperatures. Ferrite content tests can measure when the content is low and the welded material is susceptible to hot-cracking. Conversely, if the ferrite content is too high, a reduction in the toughness, ductility and corrosion-resistance of the steel can be tested. For duplex steel, a ferrite deficit in the area of the weld seam results in stress-corrosion cracking and a subsequent reduction in strength.
Ferrite testing can be carried out on-site at any stage of steel manufacturing. Only testing throughout the course of the manufacturing process can provide the assurance that the ferrite content has not been adversely affected during processing at the expense of the steel’s mechanical or corrosion-resistance properties.