Characterization of the effect of cryogenic treatment on the tempering behavior of a secondary hardening high Co-Ni steel

International Conference on Materials, Processing and Product Engineering 2015

Gruber, M.^1 ; Ressel, G.^1 ; Ploberger, S.^2 ; Marsoner, S.^1 ; Ebner, R.^1

Materials Center Leoben Forschung GmbH, Roseggerstraße 12, Leoben

A-8700, Austria^1

Böhler Edelstahl GmbH and Co KG, Mariazeller Straße 25, Kapfenberg

A-8605, Austria^2

关键词: Austenite phase;    Carbide precipitation;    Elevated temperature;    Hardness measurement;    Retained austenite;    Secondary Hardening;    Sub zero treatment;    Toughness properties;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/119/1/012018/pdf
DOI  :  10.1088/1757-899X/119/1/012018

来源: IOP

【 摘 要 】

For high Co-Ni steels sub-zero treatments are conducted to reduce the retained austenite phase fraction for obtaining excellent fracture toughness properties, but in general, cryogenic treatment has a great impact on the microstructural evolution of steels during tempering. Hence, the aim of this work was to analyze the influence of cryogenic treatments on the microstructural evolution of high Co-Ni steels, including carbide precipitation kinetics and austenite phase fraction evolution, during heating to elevated temperatures. In order to study the formation properties of carbides, the heating processes of cryogenically and non- cryogenically treated specimens were analyzed by dilatometer measurements. Furthermore, for determining the evolution of austenite phase fraction and hardness due to tempering, dilatometer investigations were combined with X-ray diffraction analyses and hardness measurements. It is revealed that sub-zero treated samples exhibit much stronger carbide precipitation signals. This was ascribed to the lower phase fraction of retained austenite, as more carbon is available for carbide precipitation.