The research deals with the description of the development of austenitic steel with TWIP effect which is alloyed with chromium to increase corrosion resistance. The experimetal heats of this steel were cast in an experimental melting furnace and subsequently subjected to hot and cold rolling. After cold rolling, the appropriate recrystallization annealing temperature was experimentally determined to obtain the optimal austenitic grain size. X-ray deffraction proved that all melts contain a fully austenitic structure. After recrystallization annealing, the sheets reach a TS of more than 950 MPa with an elongation of more than 40 %. Thanks to the addition of chromium, the corrosion resistance of this is considerably increased in comparison to standard grades of TWIP steels.
Cold Spray (CS) technology as an advanced surface treatment can also be applied in the field of energy. Depending on the type of spraying, the layer itself plays the role of protecting the surface from corrosion, abrasion and other operational influences. Deposited spray thicknesses can range from tens of microns to units of mm.
The quality of NiCr and Ni protective layers was tested in terms of attenuation, thickness of deposited layers and adhesion to the base material by pulse-echo (PEUT) and phased array (PAUT) ultrasonic testing techniques, corrosion resistance and microstructure. Evaluation of the microstructure, porosity and corrosion stability of CS coatings before and after the salt spray test was performed by metallography.
NiTi powders are coated on top surface of stainless steel. The interlayers of coating surface and interface between substrate and coating is examined by scanning electron microscopy. The quality of coating thickness is investigated by image analysis using EBSD pattern.
Keyence representative is going to present newest digital microscope VHX7000N: - flexible and high quality visual control and documentation; - metallography, grain size analysis; - spectroscopy material analysis; - 2D/3D measurements (profile, roughness and more).