DEWENTER Helge Benteler Tube Management GmbH

Effect of Rare Earth in Steel and Determination of Properties by Comparing Standard and New Methods

Co-authors RICHTER Kai, SLOMSKI Nadine, ZYLLA Isabella-Maria, BALUN Jozef, DEPIERREUX Olivier, GROSSE-HEILMANN Niko, KRONHOLZ Christian

The investigation of specimens from a low alloyed ferritic steel tube by using notch impact tests shows highly variable results in the toughness. To find the reason for this variability, a method of characterisation of the fracture surfaces by means of Scanning Electron Microscope analyses was developed. An attempt to increase the toughness or to reduce its scatter by addition of rare earth (RE) elements to the alloying concept was carried out. It is reported that the melt-treatment of steel with RE leads to an increase of toughness and to homogeneous, spherical distributed inclusions. An optimum composition was found by content variation of RE in an unalloyed steel. The heat treatments were carried out in a dilatometer. These investigations are part of the material development. To determine the mechanical properties a method of testing sub-sized samples was developed. This method increases the time and cost efficiency of material development.

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