2Cr13 (quenching, tempering) metallographic diagram

，因为文章过长 网页不允许，请改为附件

The microstructure of AISI 420/2Cr13 steel which has been heat-treated and annealed is shown in figure 1 below. The sample was taken from the mid-radius region of the bar and the size of the microstructure is magnified from hundred to several thousand times.

Figure 1: Microstructure of AISI 420/2Cr13 Steel

From figure 1, the AISI 420/2Cr13 steel consists of ferrite, pearlite, and martensite. The ferrite phase is a homogeneous, closely packed body and suggests the presence of austenite transformation. The pearlite phase is a lamellar structure composed of ferrite and cementite alternating each other. The dark light-spots in the pearlite are the result of the cementite phase in the pearlite structure. The martensite phase is present in the form of lath-like microstructures surrounded by retained austenite. This indicates that the normalized-and-tempered heat treatment was successful in converting the retained austentie into martensite.

The size and shape of the ferrite grains is uniform, suggesting that it was formed by uniformly growing ferrite grains from the austenite. The ratio of ferrite to pearlite is also consistent, suggesting a suitable temperature range for the transformation from austenite to ferrite.

The heat-treatment of the steel has resulted in an increase in the number of ferrite grains, as compared to the original austenitic state. The size of these ferrite grains has also increased as compared to the original austenite. This increase in size has resulted in a decrease in the overall strength of the steel, but at the same time an increase in the ductility. Additionally, the annealing of the steel has resulted in a uniform increase in the size of the ferrite and pearlite grains, as well as a decrease in the amount of retained austenite. This has resulted in an overall improvement in the mechanical properties of the steel.

In conclusion, the heat-treated and annealed AISI 420/2Cr13 steel has a microstructure consisting of ferrite, pearlite, and martensite grains. The size and shape of the ferrite grains is uniform, and the ratio of ferrite to pearlite is consistent. The heat treatment has resulted in an increase in the number of ferrite grains and a decrease in the amount of retained austenite. The annealing has resulted in a uniform increase in the size of ferrite and pearlite grains, as well as an improvement in the mechanical properties of the steel.

The microstructure of 420 stainless steel after heat treatment is shown in the diagram. It is composed of austenite and martensite, and small particles of carbides, which are distributed on the boundary of austenite-martensite.

420 stainless steel is a kind of martensitic stainless steel, due to its special production process, it has a very good heat resistance, wear resistance and corrosion resistance. It has been widely used in the fields of machinery, electronics and construction materials.

Since 420 stainless steel is martensitic, when it is heated to a certain temperature, martensite is easy to form and it has the martensitic structure. Therefore, after heat treatment of 420 stainless steel, it has a certain proportion of austenite and martensite, and carbide particles precipitated on the boundary of austenite and martensite, which enlarges its hardness and wear resistance.

In order to ensure the best performance of 420 stainless steel, after heat treatment, it needs to be quenched and tempered. When the temperature is above the transformation temperature Ac3, it will form austenite (γ) and then be quenched. After quenching, it produces martensite, and then temper it to get martensite plus small ferrite or tempered sorbite, which improves the toughness and plasticity of 426 stainless steel and makes it have better comprehensive mechanical properties.

In addition, as long as 420 stainless steel can be quenched and tempered, the scale pattern and microstructure of it will be the same as the diagram. The 420 stainless steel with this microstructure can get the best performance in its application.