Metallographic diagram of 25CrNi3MoV (refined and tempered)

25CrNi3MoV(Tempered) Metallographic Characteristics

25CrNi3MoV (Tempered) is a high alloy steel engineered for use in applications that require extreme wear and corrosion resistance. The alloy is characterized by a combination of high strength and toughness, as well as an excellent resistance to a range of corrosive and extreme temperatures. Additionally, 25CrNi3MoV (Tempered) is exceptionally strong and robust while maintaining good ductility and being comparatively easier to form and shape than other metals.

Metallographic examination of 25CrNi3MoV (Tempered) can be used to investigate its chemical composition, grain size and distribution, and internal microstructure. This examination enables better characterization of the microstructure, which further helps in the evaluation and selection of this impact-resistant alloy.

Metallographic examination of 25CrNi3MoV (Tempered) requires a suitable flat sample, typically cut from the edge or end of a blank. It is also important to ensure a semi-polished surface for the examination, so that imperfections such as inclusions can be seen clearly.

The chemical analysis of 25CrNi3MoV(Tempered) through Optisken analyzer reveals that the alloy chiefly consists of 25% Chromium, 3% Nickel and 0.25% Molybdenum. The remainder of the alloy is made of other elements such as Carbon, Phosphorus, Sulfur, Manganese and Silica.

The grain size of 25CrNi3MoV (Tempered) is divided into five categories, namely, Belsite, microlite, micrite, granular, and monofilament. This classification is based on the usable grain size range. A Belsite grain size is normally considered when the material is heat treated and has an average grain size of 0.2–0.9mm. The microlite grain size is generally chosen when the material is cold worked, with an average grain size of 0.14–0.2mm. The micrite grain size range is available when a finer grain size is desired, with an average grain size of 0.07–0.14mm. Granular grains can also be produced, with an average grain size range of 0.03–0.07mm. The monofilament grain size range is typically used when a very fine grain size is desired, with an average grain size of 0.01–0.03mm.

Analysis of the internal microstructure further reveals that the 25CrNi3MoV(Tempered) contains ferrite (α-Fe) and austenite (γ-Fe) as its major constituents. The ferrite is present in a finely dispersed form and exhibits a rod like shape. The austenite, on the other hand, appears in a coarser manner and is characterized by a blocky structure. In addition, the electron micrograph of 25CrNi3MoV(Tempered) also shows the presence of several micro-alloying elements such as niobium and vanadium, which are present in the form of carbides, nitrides and phosphides.

Overall, metallographic examination gives us an understanding of the metallurgical structure and composition of the 25CrNi3MoV (Tempered) alloy, which helps in its evaluation and selection. This high alloy steel is particularly suitable for applications requiring extreme wear and corrosion resistance.

25CrNi3MoV is an alloy steel with a medium concentration of chromium and nickel. This steel has great hot workability, toughness and is also used for cold construction work. It has good machinability, weldability, and is also known for its good corrosion resistance.

The microstructural analysis of 25CrNi3MoV after tempering showed the presence of the expected tempered martensite with some bainite and secondary carbides. The tempered martensite appeared in a grid-like pattern, with a fine ferrite matrix. The secondary carbides were in the form of islands, mainly comprising M7C3 and M23C6 type. Bainite also was visible in the form of thin sheets, mixed with the other constituents.

The tensile properties of the alloy before and after tempering were also assessed. The results were expected compared to the studies of similar alloys. The yield strength increased significantly due to the tempering process. The tensile strength and elongation were reduced after tempering.

The overall performance of the alloy was satisfactory and it can be used for various applications, including steam turbines and other high temperature systems where good corrosion resistance and heat resistance are required.

Therefore, the 25CrNi3MoV alloy is suitable for various applications in different industries, after tempering. Its superior properties such as good hot workability, machinability, weldability, and corrosion resistance make it a desirable material for many applications.