2Cr13 (annealing treatment) metallographic diagram

An Investigation of the Martensitic Transformation in AISI 420 Heat Treated Steel

This paper is an investigation of the martensitic transformation in AISI 420 heat treated steel. AISI 420 Steel is a martensitic stainless steel, widely used in the industrial and naval fields due to its excellent toughness. This steel is widely used for blade Steels, biopsy needles, doctor blades and surgical instruments, as well as other precision components. Its unique physical properties, such as good strength and toughness, make it especially suitable for the manufacturing of cutting tools, for the food industry and in other applications where there is a need for corrosion resistance and wear resistance.

In order to evaluate the martensitic transformation in AISI 420 steel, a series of heat treatments were performed. AISI 420 Steel was first annealed and then heated to different temperatures in order to study the variation of hardness and microstructural features. It was found that the hardness of AISI 420 steel increased after heat treatment. X-ray diffraction patterns showed that the martensite peaks appeared at different angles, indicating the presence of different phases in the alloy.

Grains sizes in the microstructure were observed in the SEM images and have increased following the heat treatment. Using polarized light, it was possible to observe the typical martensite microstructures of AISI 420, as well as other phases likely to be present, such as retained austenite and bainite.

It was then carried out an analysis of microstructural changes following the heat treatment of AISI 420 Steel, in order to determine the effect of heat on the hardness and microstructure of the metal. The results of the investigations carried out in this study showed that AISI 420 steel can be successfully heat treated and hardened by the martensite transformation. This metal showed an increase in hardness with the highest value at 950 °C and an increase in grain size which were clearly seen in the SEM images.

Therefore, in conclusion, this investigation has shown that AISI 420 steel can be successfully heat treated by martensite transformation. The heat treatment improved the hardness and also changed the microstructure of the material. The heat treatment also altered the microstructure of the material, leading to an increase in grain size. Furthermore, these changes can be used to tailor the properties of the material and to design components with specific properties better suited for various applications.

A metallographic sample of AISI 420/2Cr13 after annealing was observed in order to identify the phases present. The sample consists of a homogenous alloy matrix composed of ferrites and carbides.

In the microstructure, the carbides are irregularly distributed and form a somewhat discontinuous network. The majority of these have an acicular morphology with a size of 10-25 μm in length and 1-2 μm in width. The carbides are distributed largely throughout the matrix and near the grain boundaries.

Ferrite grains are relatively small and have an average size of 0.5 mm. These are mostly elongated, but some round grains can also be observed. The ferrite grains often have some undulations and the grain boundaries have a jagged appearance. The majority of ferrite grains are stringers with a size of 5-10 μm.

The sample was slowly cooled in order to improve its mechanical properties. It exhibited a slow cooling rate and the presence of fine grain structures. This helped to improve its ductility due to the presence of ferrite with austenite and carbide refinement.

The results of the metallography investigation concluded that the sample of AISI 420/2Cr13 after annealing mainly consists of ferrite, along with some austenite and carbide particles. The ferrite phase contributes to its ductility properties, and the presence of the carbide phase helps to improve the hardness and wear resistance of the material.