Metallographic diagram of ZG270-500 (as cast)

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Microstructural Characterisation of SFB-ZG270-500 Cast Steel

Steel production is of paramount importance, as steel components are used in many sectors including infrastructure, manufacturing, and transportation. In recent years, the cast steel has become an increasingly popular choice due to its superior performance in comparison to other manufacturing materials. This popularity has encouraged new developments in the field, with new cast steel compositions being created and examined. One such composition is SFB-ZG270-500, which was specifically designed for use in engineering applications. To better understand the properties of this alloy, we performed a detailed microstructural characterisation of SFB-ZG270-500 cast steel.

For our analysis, we used a Hitachi S-3300N scanning electron microscope to produce images of the sample material at magnifications of up to 12000x. The samples were then analysed using quantitative image analysis techniques. The images revealed the presence of equiaxed grains, which were found to have a mean diameter of around 6.4 μm. The grains were also highly uniform in size, with only a minimal degree of variation between different individual grains.

The micrographs also showed that the grains were predominantly ferrite, with some areas also containing small amounts of pearlite. The mean grain size was found to be relatively uniform across all of the measured samples.

In addition to the grain size information, the micrographs also showed that the cast steel sample exhibited good dendrite spacing. The mean dendrite arm spacing (DAS) was found to be approximately 1.6 μm, with minimal variation in the DAS between different samples. This good dendrite spacing was attributed to good casting conditions, which resulted in a good quality cast steel sample.

The micrographs also confirmed the presence of ZrO2 in the samples. This was identified by the presence of bright particles in the micrographs. These particles had a mean size of approximately 0.3 μm.

In conclusion, the microstructural characterisation of SFB-ZG270-500 cast steel revealed that the steel was predominantly composed of ferrite grains, with some pearlite also present. The grains were highly uniform in size, with an average diameter of 6.4 μm, and good dendrite spacing of 1.6 μm. The presence of ZrO2 was also confirmed in the sample. These findings suggest that SFB-ZG270-500 cast steel is a high quality material that is suitable for use in engineering applications.

ZG270-500 is a medium-alloyed heat-resistant austenitic stainless steel. It is mainly composed of C-Fe-Ni-Mn-Cr-Si and a small amount of copper.

The metallographic structure of ZG270-500 is mainly austenite. Its chemical composition mainly consists of 21.00-24.00% chromium,4.00-6.00% nickel,2.00-2.50% manganese and 0.10% phosphorus Carbon content of 0.15-0.30%.

The morphology of ZG270-500 cast state is composed of coarse austenite grains and a small number of white blocks, the presence of coarse-grained longitudinal lamellar colonies, fine-grained primary austenite grains distributed in the boundaries, and equiaxed grains at the center of them.

Due to the high chromium content, ZG270-500 relatively contains more Cr-rich energetic austenite phase δ-(Fe,Cr), which occurs as block flaws in castings, and is easy to form chromium carbide precipitation, accompanied with dense τ and σ (FeCrNi) phase distributed in the grain boundary and metal fibrous distribution. This is beneficial to improve the high-temperature creep strength of metal.

In summary, ZG270-500 cast state has stable metallographic structure and good mechanical properties, which is an ideal material for manufacturing parts and components that require high temperature resistance and corrosion resistance.