35CrMo (slowly cooled after forging) low-magnification structure and non-metallic inclusions

Introduction

Microstructural and non-metallic inclusions characterization of forged 35CrMo(elongated with slow cooling) steel has been studied. This research was intended to develop better understanding and knowledge of the influence of forging and cooling conditions on the formation of microstructures and non metallic inclusions. Samples of 35CrMo steel after forging and slow cooling have been selected and analyzed using optical, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques.

35CrMo Steel

35CrMo steel is a ferrous alloy composed mainly of iron and chromium, with a small amount of carbon, molybdenum, and other alloying elements. 35CrMo steel is mainly used to make high strength automotive parts, turbines and other machinery, as well as oil and chemical pipelines.

Experimental Details

The experiment was performed on a 35CrMo steel sample after forging and slow cooling. The sample was cut into two parts for optical and SEM/EDS investigations. Optical microscopy was used to observe the microstructure of the steel, and observation was done at various magnifications (x10 and x50). After this, the SEM/EDS technique was used to analyze non-metallic inclusions in the sample.

Results and Discussion

Optical microscopy revealed that the microstructure of the 35CrMo steel consisted of a ferritic matrix with undeformed pearlite bands, showing a bimodal grain structure. The grains were of medium size, and no deformation twins or disintegration into fragments was observed.

Non-metallic inclusions were also identified and characterized using the SEM/EDS technique. The non-metallic inclusions related to oxidation processes formed by the presence of oxygen in the steel, such as silicon compounds, aluminum silicates, and alumina. The analysis of non-metallic inclusions also revealed that the concentration of Al2O3, SiO2, and MgO were higher than that of Cr2O3.

Conclusion

Microstructural and non-metallic inclusion characterization of forged 35CrMo steel elongated with slow cooling has been studied. Results from optical microscopy revealed a ferritic matrix with undeformed pearlite bands, showing a bimodal grain structure. Non-metallic inclusions found in the sample were related to oxidation processes, and the concentration of Al2O3, SiO2, and MgO were higher than that of Cr2O3. This research has provided a better understanding and knowledge of the influence of forging and cooling conditions on the formation of microstructures and non metallic inclusions.

Material 35CrMo is a low-alloy heat-treatable steel consisting of chromium, molybdenum, and carbon. It is known for its excellent wear resistance, toughness, strength and ductility and is commonly used in the automotive, oil & gas and aerospace industries.

Due to its advantageous material characteristics, this material has been widely applied for a variety of applications. For example, in the automotive industry, it is used for the manufacture of drive shafts, gears and other components. In the oil and gas sector, it is often utilized for fasteners, valves and other components in metal fatigue applications. In aerospace, it is used for fabricating aerospace structures, components and fasteners.

Material 35CrMo has gone through heat treatment after forging. This process involves quenching in a furnace to rapidly cool the metal and reduce its overall temperature. This allows the microstructure to become more uniform across the entire piece, leading to improvements in strength and toughness. In order to further improve the microstructure, non-metallic inclusions can be introduced during the heat treatment process. This helps to refine the material, improving its ductility.

Overall, material 35CrMo is a versatile low-alloy steel with excellent wear resistance, toughness, strength and ductility. Through proper heat treatment, its microstructure can be further refined and non-metallic inclusions can be introduced, allowing it to be used in a variety of applications.