Temperature Depending Influence of the Martensite Formation on the Mechanical Properties of High-Alloyed Cr-Mn-Ni As-Cast Steels

The temperature dependence of the martensite formation and the mechanical properties of three high alloyed Cr-Mn-Ni as-cast steels with varying Ni contents were studied. The results showed that the Ms and Md temperatures of the steels decrease with increasing nickel contents. Therefore the strain-induced martensite formation, the TRIP effect and the temperature anomaly of the elongations occurs at lower temperatures. The steel alloyed with 3% nickel shows a stress induced formation of martensite and a dynamic strain aging. Depending on the nickel content and the temperature a TWIP effect occurs additionally to the TRIP effect in the investigated steels. The study was performed by using static tensile tests, dilatometer tests, optical microscopy and the magnetic scale for the detection of ferromagnetic phase fractions.