Effects of hot working procedure on surface relief characteristic in an Fe–Mn–Si–Cr shape memory alloy

The paper reports the evolution of surface relief and shape memory behavior in an Fe–28Mn–6Si–5Cr (mass%) shape memory alloy (SMA) as a function of the applied hot working procedure. The objective of this paper is to discuss the relationship between surface relief characteristic, structural changes and the type of hot working processing. Particular aspects concerning the relief of martensite plates were reported after the alloy was subjected to two types of hot working procedures, namely hot rolling and hot forging at 1273 K. The observations were performed by means of optical (OM) and atomic force (AFM) microscopy, on bi‐dimensional and three‐dimensional micrographs, corroborated with statistical evaluations. Aiming to reveal the presence of solid phase transitions enabled by hot working, differential scanning calorimetry (DSC) measurements were performed between room temperature and 673 K.     

Versuche und Anwendung hochfrequenter Hämmerverfahren als Schweißnahtnachbehandlung

Die Lebensdauer von dynamisch belasteten Bauteilen aus Stahl stellt ein entscheidendes Qualitätsmerkmal von Produkten der Stahlbau Firmen dar. Der Einsatz höherfrequenter Hämmerverfahren, im Besonderen des UIT oder HiFIT‐Verfahrens, als lebensdauerverlängernde Maßnahme von ermüdungsbeanspruchten Schweißverbindungen wurde im Rahmen des REFRESH‐Forschungsprojekts erstmals wissenschaftlich untersucht. Einsatz und Wirksamkeit der Verfahren wurde von den am Projekt beteiligten Firmen an ausgeführten Bauteilen untersucht. Die Erkenntnisse aus Versuchen und praktischer Anwendung der Firmen Schachtbau Nordhausen und Maurer Söhne werden im folgenden Artikel geschildert. Tests and application of high frequency peening as a post weld treatment method. The fatigue life of dynamic loaded steel construction elements is an influential quality characteristic for products of steel fabricators. The application of high frequency peening, especially the UIT (ultrasonic impact treatment) or the HiFIT (high frequency impact treatment) as a method to extend the fatigue life of welded connections, has been investigated in course of the research project called REFRESH for the first time. The practical application and the effectiveness of high frequency peening at finished building components have been examined by building companies which are concerned to the research project. The present paper describes the tests and the practical application of the companies Schachtbau Nordhausen and Maurer Söhne.