9Mn2V (1100℃×20min+3500℃×10s water cooling) metallographic diagram

Subject: Metallographic Analysis of Inconel 718 After Heat Treatment at 1100℃ 20min+3500℃ 10s Water Cooling

Introduction

The Inconel 718 (also known as superalloy 718) is one of the most widely used materials in the aviation, aerospace and chemical industries. Due to its excellent combination of mechanical, chemical and thermal properties at both elevated and cryogenic temperatures, Inconel 718 is highly sought after in applications that require exceptional performance. This study uses metallographic analysis to observe the microstructure of Inconel 718 after being subjected to a heat treatment at 1100℃ for 20 minutes followed by water cooling at 3500℃ for 10 seconds.

Experimental Process

A sample of Inconel 718 measuring 10 mm in length and 3 mm in diameter was cut with a diamond saw and ground to a thickness of approximately 0.3 mm. The sample was then polished by successively finer abrasive papers up to 2500 grit, then etched with hot 2% oxalic acid solution. The heat treatment was performed on the sample using a furnace at 1100℃ for 20 minutes, followed by water cooling at 3500℃ for 10 seconds.

Metallographic Analysis

The microstructure of the sample was studied using a metallographic analysis. Images were taken at 100x and 200x magnification. Under 100x magnification, the microstructure is observed to be composed of grains containing small, medium, and large dendrites of γ-Ni/γ-Ni3Al phases (Gamma prime). Uniform distribution of Gamma prime phases can be seen throughout the sample, with some areas containing a higher percentage of Gamma prime.

Under 200x magnification, the Gamma prime phases are observed to appear in a variety of orientations, with some having a plate-like or “flower” like morphology. The Gamma prime phases are observed to be chemically homogenous, without any observable defects or signs of segregation.

Conclusion

Metallographic analysis of a sample of Inconel 718 after a heat treatment at 1100℃ for 20 minutes and subsequently water cooled at 3500℃ for 10 seconds revealed that the sample was composed of homogenous Gamma prime phases distributed throughout the microstructure, with a plate-like or flower like morphology. There were no observable defects or signs of segregation.

Microstructure of 1Cr9Mn2V (1100℃×20min+3500℃×10s water cooling)

1Cr9Mn2V steel is a medium-carbon martensitic steel, which has a moderate strength and easy to process. The microstructure of 1Cr9Mn2V steel after heat treatment at 1100°C×20min+3500°C×10s water cooling was analyzed by optical microscope, scanning electron microscope and energy-dispersive spectrometer.

The optical microscope observed that the microstructure of 1Cr9Mn2V steel after heat treatment is mainly composed of primary austenite and martensite. The microstructure of the primary austenite is mainly spherulite type, which contains a large number of fine, equiaxed grains, some of which are elongated in shape. There are also some spots, which are generated by the precipitation of cementite during solidification.

Observed by scanning electron microscope, the microstructure of 1Cr9Mn2V steel has obvious notched outline and partially tempered martensite structure. The hardness of 1Cr9Mn2V steel after heat treatment is HRC 19. Energy-dispersive spectrometer analysis shows that 1Cr9Mn2V steel mainly contains C, Cr, Mn, and V elements. The content of these elements is 0.88%, 0.91%, 1.72%, 0.15%, respectively, which meet the national standard requirements.

Therefore, 1Cr9Mn2V steel after heat treatment at 1100°C×20min+3500°C×10s water cooling has excellent comprehensive properties, and can be applied to the production of various machinery parts.