The aim of this paper is to create a research methodology that allows a quick analysis of the structural state of high alloy austenitic steels using non-destructive ultrasonic tests, in contrast to destructive standard methods. Electromagnetic acoustic transducers (EMAT) are used to generate and receive the ultrasonic wave and detect the microstructural changes caused by sample sensitization in elevated temperature, even after 0.5 h in high temperature exposition. Different acoustic response for reference sample and sensitized samples were recorded. In this work, changes in share wave amplitude were measured.

This paper presents the results of Cr - Ni 18/9 austenitic cast steel modifications by mischmetal. The study was conducted on industrial melts. Cast steel was melted in an electric induction furnace with a capacity of 2000 kg and a basic lining crucible. .The mischmetal was introduced into the ladle during tapping of the cast steel from the furnace. The effectiveness of modification was examined with the carbon content of 0.1% and the presence of δ ferrite in the structure of cast steel stabilized with titanium. The changes in the structure of cast steel and their effect on mechanical properties and intergranular corrosion were studied. It was found that rare earth metals decrease the sulfur content in cast steel and above all, they cause a distinct change in morphology of the δ ferrite and non-metallic inclusions. These changes have improved mechanical properties. R02, Rm, and A5 and toughness increased significantly. There was a great increase of the resistance to intergranular corrosion in the Huey test. The study confirmed the high efficiency of cast steel modification by mischmetal in industrial environments. The final effect of modification depends on the form and manner of placing mischmetal into the liquid metal and the melting technology, ie the degree of deoxidation and desulfurization of the metal in the furnace.

The paper presents the research results of the solenoid housing made of the Zn4Al1Cu alloy that was destroyed as a result of corrosion.

Surface of the tested part showed macroscopically the features typical for white corrosion, and the resulting corrosion changes led to a

disturbance of the alloy cohesion. The research performed have shown that the tested solenoid valve has intergranular corrosion as a

reaction of the environment containing road salt. The corrosion was initiated in the areas of the alfa phase existence appearing in the

eutectic areas which propagated over dendritic areas of the alloy. Initiation of the corrosion followed as a result of the galvanic effect of

the alfa phase reach in aluminium showing higher electrochemical potential, in contact with the eta phase reach in zinc. The impact of the

phase reach in lead present in the microstructure on the corrosion processes run was not found.