pomiar grubości ferrytuDetermination of ferrite content is usually conducted on welded joints of steel with an austenitic microstructure. It is also sometimes conducted on plated steels after pad welding, the substrate of which has a ferritic-pearlitic microstructure, and the plating of which has an austenitic microstructure. As a result of welding processes, mixing of the filler metal with the native material takes place.
A correctly selected welding technique, welding materials, and welding parameters should guarantee ferrite content within the range of 2 to 8% in an austenitic weld in the case of manual welding and up to 10% in the case of automatic welding. The appropriate ferrite content in metal after welding prevents the possibility of hot cracking. This is the effect of much better solubility of impurities in ferrite than in austenite.