4Cr10Si2Mo (oil quenching and tempering) metallographic diagram

4Cr10Si2Mo(Oil-quenched and tempered) Microstructure and Metallography

4Cr10Si2Mo is an oil-quenched and tempered steel commonly used in the automotive and aerospace industries. The chemical compositions of 4Cr10Si2Mo range slightly depending on the application. In general, the alloy contains 4% chromium, 10% silicon and 2% molybdenum. The remainder of the alloy is composed of iron and trace amounts of other metals. The steel is known for its high hardness, wear resistance and fatigue strength, which make it ideal for high-temperature and high-stress aerospace and automotive components.

In order to gain a better understanding of the microstructure of 4Cr10Si2Mo, a metallographic examination was conducted. The sample was prepared by first polishing the specimen using a series of increasingly finer abrasive papers. The sample was then etched with a 10% nitric acid solution to reveal the microstructure. The microstructure was then examined using an optical microscope with a magnification of up to 500x.

The optical microscope revealed the steel to have a predominantly ferritic microstructure, with some areas of pearlite present. The ferrite grains were relatively small and elongated, with a regular distribution. The pearlite was observed to have a more coarse texture with larger grain sizes than the ferrite. The grain boundaries were also observed to be sharp and distinct.

The presence of both ferrite and pearlite is indicative of a martensitic structure in 4Cr10Si2Mo. The martensitic structure imparts the strength and wear resistance to the steel. The pearlite formed by the transformation of ferrite during the tempering process imparts the steel with additional strength and toughness.

The microstructure of 4Cr10Si2Mo was seen to be very uniform due to the controlled cooling of the steel. The alloying elements in the steel were found to be evenly distributed, allowing for consistent mechanical properties throughout the material. The uniformity further contributes to the high strength, wear resistance and fatigue strength of the steel.

Overall, 4Cr10Si2Mo is a high-performance steel that is ideal for high-stress, high-temperature applications. The controlled cooling of the steel leads to a homogenous microstructure of ferrite and pearlite, which impart the steel with excellent mechanical properties. The alloying elements are well distributed to ensure uniform mechanical properties throughout, contributing to the strength and wear resistance of the material.

4Cr10Si2Mo(oil quenched and tempered) is a high-carbon chromium steel with low sulfur, adapted for use in oil hardening and tempering. It is composed of 4.0 wt% of Carbon (C), 10.0 wt% of Chromium (Cr), 2.0 wt% of Silicon (Si) and 0.8 wt% of Molybdenum (Mo). This steel is widely used in oil-hardened and tempered application due to its combination of high strength and good dimensional stability.

In comparison to the conventional water-hardening grades, the oil-hardened and tempered grade is hard to machine and may require special attention when machining or heat-treating. Depending on the intended application and processing requirements, 4Cr10Si2Mo can be further treated with several methods, including annealing and cold-working, to improve its performance.

When heated, 4Cr10Si2Mo has a fairly even transformation from austenite to martensite, though it is slightly slower than a conventional water-hardening grade due to its higher carbon content. The relatively low alloy content creates a microstructure of primarily martensite and small amounts of evenly distributed dispersed ferrite. Depending on the exact heat treatment, 4Cr10Si2Mo can further have pearlitic or bainitic microstructures in addition to martensitic.

The microstructure of 4Cr10Si2Mo is highly rigid, which leads to good wear resistance as well as toughness and strength. It is not as strong as some of the high strength water-hardening grades, but still has a high tensile strength of about 1720 MPa. The yield strength is greater than 1100MPa and the hardness is approximately 220HB. Additionally, 4Cr10Si2Mo has an excellent ductility with elongation values in excess of 15%.

Due to 4Cr10Si2Mo’s excellent strength, toughness and wear resistance, it is commonly used for components in power transmission and automotive applications.It can also be utilized in other applications, such as tools and dies, where strength, hardness and dimensional stability are required.