Metallographic diagram of powder metallurgy sintered carbon steel (oxidation treatment)

Analysis of Microstructure of Carbon Steel Sintered by Powder Metallurgy (Oxidation Treatment)

Powder metallurgy (PM) combines powder and compaction technology to form dense parts with complex geometries, allowing a wide range of materials and structures to be produced. PM processes are widely used in the manufacture of products, tools and wear parts. In this paper, the microstructure of carbon steel sintered by powder metallurgy and process with oxidation treatment was studied to understand the effect of the oxidation treatment on the microstructure of sintered carbon steel.

A commercially available low-carbon steel powder with average particle size of 17μm was used to produce the sintered carbon steel. The sintered parts were then treated with oxidation, characterized and observed by optical microscopy and tested with x-ray diffraction (XRD) analysis to study the microstructure.

The microstructures of sintered carbon steel after oxidation process were examined by optical microscopy. The microstructure of the sintered parts showed the presence of uniform circular pores in the matrix, indicating the existence of air gaps between sintering powders, leading to a porous microstructure. The oxidation process had a small effect on the surface morphology, but spectroscopic analysis revealed that the porosity was slightly reduced, which may be attributed to the conversion of some carbon-containing elements to oxide.

In addition, XRD analysis of the sintered samples showed that the as-sintered material had an Fe phase of 97.1%, and the phase after the oxidation process had a conversion rate of 96.9%. This result indicated that the oxidation process had little effect on the Fe phase of the sintered steel, while C, Si and Mn were slightly oxidized, and Cu, Ni and Mo were significantly oxidized, such as Mn (1.1%) after oxidation process, which was converted to MnO.

The optical microscopy showed that the microstructure of sintered carbon steel was mainly composed of ferrite. With increasing oxidation time, the amount of ferrite increased slightly, accompanied by an increase in grain size and a decrease in ferrite grain boundary area. In addition, the oxidation process also caused a slight thinning of the film, which is beneficial to the surface wear resistance by increasing the hardness of the surface.

From the above analysis, it is concluded that the oxidation treatment can significantly improve the microstructure of sintered carbon steel. The oxidation treatment has little effect on the crystal structure of Fe component, but has a significant effect on the conversion rate of carbon, silicon and other elements. In addition, the oxidation treatment can further reduce the porosity, increase the hardness of the surface layer and improve its wear resistance.

Metallography of Medium-Carbon Steel Sintered by Powder Metallurgy (Oxide Treatment)

Medium-carbon steel sintered by powder metallurgy with oxide treatment is a material widely used in the manufacturing industry. In order to understand its internal structure and performance, the metallographic structure of this material needs to be analyzed.

This sample was prepared by mounting in an epoxy resin and polishing with successively finer abrasives. Etching with 2% nitric acid reveals the ferrite, pearlite and carbide phases present in the structure. The microstructure shows a uniform distribution of small and relatively homogeneous pearlite colonies with few carbides. The small, fine ferritic and pearlite grains give the sintered medium-carbon steel an excellent mechanical strength and toughness.

Analysis of the crystal structure of the material by X-ray diffraction reveals the presence of austenite and ferrite phases in addition to the carbides. The ferrite is present in the form of fine colonies and the austenite is distributed in discrete areas. The microstructure also shows a uniform distribution of compound phases, consisting of a mixture of ferrite, austenite and carbides. This gives the sintered material a strong resistance to wear, making it ideal for use in the manufacture of tools and machinery components.

In conclusion, the metallographic structure of the sintered medium-carbon steel with oxide treatment reveals a uniform distribution of ferrite, pearlite and carbide phases. The presence of fine ferrite colonies, discrete austenite and a uniform mixture of ferrite, austenite and carbides gives the material an excellent mechanical strength and wear resistance. Therefore, this material is well suited for use in a variety of industrial applications.