Metallographic diagram of 45 steel, Φ18mm bar (hot-rolled state)

A Brief Introduction to the Metallographic Analysis of 45# Steel with a Diameter of 18mm Hot-Rolled Bar

Metallographic analysis is one of the important techniques used in metallurgical research. By analyzing the metallographic microstructure of a material, we can quickly determine its performance, heat treatment process and other technical parameters. In the following article, we will analyze the metallographic microstructure of a 45# steel rod with a diameter of 18mm in the hot-rolled state.

Metallographic analysis of 45# steel rods with a diameter of 18mm is typically performed in three steps. First, the necessary tools and equipment are collected and set up to observe the specimen under a microscope. Second, the specimen is cut out into slices and prepared for metallography. Third, the specimen is analyzed for its physical and chemical composition.

In the first step, a metallographic microscope is used to observe the microstructure of the specimen by stages. In this case, the specimen is a 45# steel rod with a diameter of 18mm. All metals contain grains, which are the basic units that determine the structure of the material. An analysis of the size, shape, orientation, and distribution of these grains can tell us a lot about the metallurgical properties of the material.

In the second step, the specimen is cut into multiple thin slices. This is done using a diamond wheel, which is then mounted on a metallographic clip. The slices are then ground and polished using appropriate abrasives. This process is necessary to create a flat, even surface for observation under the microscope.

In the third step, the slices of the specimen are analyzed for their physical and chemical composition. This process involves measuring the thickness, grain size, porosity, hardness, and strength of the material. The morphology and size distribution of the grains can also be determined. In this case, the grains of the 45# steel have a roughly equiaxed, dendritic shape.

The analysis of the metallographic microstructure of 45# steel with a diameter of 18mm has shown that it has a high ductility and toughness, which makes it suitable for a variety of applications. It also has a low carbon content and good hardness, which makes it well-suited for machining and the formation of parts. The metallographic analysis has also revealed that the material has a homogeneous microstructure and good surface quality. This makes it a good candidate for use in applications that require high precision, durability, and strength.

Metallography is an invaluable tool for understanding the properties and performance of metals and other materials. In this article, we have described the application of metallography to analyze the metallographic microstructure of a 45# steel rod with a diameter of 18mm in the hot-rolled state. The results of this analysis provide valuable information about the properties and performance of the material. This information can be used to make informed decisions about how best to use the material in different applications.

This is an optical micrograph of low carbon steel （45#）with diameter of 18 mm, which was in its hot forged state. As showed in the picture, most of the strucutre of the sample is composed of ferrite, which appears light gray and has a lower hardness, better extensibility and higher ductility compared with other three types of ferrous materials . Besides, there are a few of dispersed pearlite between the ferrite, which are dark gray and harder than ferrite. It also shows some black spots which were originated from non-metallic inclusions.

The black spots are mainly made up of alumite, silicate and other oxides which were trapped during the solidification process. Besides, It can be seen that the nickel-rich channels that formed in the face-centered cubic lattice at the boundary of ferrite and pearlite, making it appear slightly brighter.

This sample has undergone a hot-rolling process with high temperature and pressure. The microstructure we observed is fruitful in providing some meaningful data. Generally, the high temperature worked on the iron atoms and orginally formed round particles, which gradually changed into balck spots. By the influence of pressure, the black spots were squeezed and formed the microstructure of ferrite and pearlite, with nickel-rich channels on the boundary.

The structure observed was consistent with the expected result. Steel （45#）has a high ductility, which makes it an ideal material for hot-rolling. The microstructure of the sample, with mainly ferrite and a few of dispersed pearlite, is an ideal condition for hot-rolling, for it can maintain the good extensibility and plasticity. This means the heat treatment of the sample has been conducted properly and the material properties reached our expectations.