Physical metallurgy of a HSS material for hot rolling mill rolls

peer reviewedHigh Speed Steel (HSS) cast rolls are used in front finishing stands of hot strip mills. Good wear resistance and hardness at high temperatures, are defining features of HSS. Many types of carbides are present in these alloys, each having different effect upon their final properties. As a result, nature, morphology and amount of these carbides are factors of important concern. Identification and characterisation of carbides were realised. MC, M2C, M7C3 carbides were found. Some relationships with mechanical properties were obtained especially in the field of the solidification sequence that affects grain size and carbides dispersion

Image analysis of carbides in high speed steel rolls and their relationship with the mechanical properties

Image analysis is used to describe quantitatively various different natures of carbides in high speed steel rolls. After an etching judiciously selected, the identification and the extraction of the carbide types are based on spectral differences. For every carbide type, three parameters are measure : the size, the spatial distribution and the volume fraction. The size of martensite grain is also measured

Quantitative description of MC, M2C, M6C and M7C3 carbides in high speed steel rolls

peer reviewedOne goal of the COST 517 project entitled “Effects of inclusions and carbides on the mechanical properties of alloyed steels” is to establish quantitative and statistical relations between the microstructure and the mechanical properties of rolls materials. This paper presents the different steps necessary to characterise the microstructure and the carbides presents in high-speed steel rolls. First, carbides were examined by SEM and EDX microscopy. Then, images of samples were acquired by optical microscopy and analysed to finally measure quantitative parameters describing the grains and the carbides