Metallographic diagram of 20Cr and Q235 (20Cr steel friction welding after carburizing and quenching)

The microstructure and properties of Q235 and 20Cr steels

The strength and other properties of many materials are determined by their microstructure. In this study, the microstructure and properties of Q235 and 20Cr steels are compared. 20Cr steel is an improved version of Q235, which is a low-alloy steel.

Q235 steel is composed of ferrite, pearlite, and traces of carbide, whereas 20Cr steel contains an increased amount of carbide. 20Cr steel also contains alite or ferrite-carbide composite phases. The microstructure of 20Cr steel is substantially different from that of the Q235 steel due to the large amount of carbide-alite in the lattice. The microstructure of 20Cr steel provides higher strength and wear resistance.

An analysis of the micro-hardness of Q235 and 20Cr steels found that the former is softer than the latter. This is due to the increased hardness associated with the presence of carbide in the alloy structure of 20Cr steel. However, the strain-life properties of the two steels were found to be similar. This is due to the fact that both steels possess an identical yield strength, which is the ultimate indicator of the ability of a material to resist fatigue. Additionally, the strains experienced under dynamic loading are similar for both materials.

The thermomechanical properties of Q235 and 20Cr steels have also been investigated. Analysis of the fracture toughness of the two steels showed that 20Cr steel possessed higher fracture toughness compared to Q235 steel. This is attributed to the presence of the alite in the alloy structure, which makes 20Cr steel stronger and more ductile, allowing it to resist cracks more effectively.

The microstructure and properties of Q235 and 20Cr steels were observed after they were subjected to carburizing and tuff and scalpel abrasion treatments. The carburizing treatment improved the hardness of both steels, while the tuff and scalpel abrasion treatments improved the wear resistance of 20Cr steel.

In conclusion, 20Cr steel has a more complex alloy structure than Q235 steel, which provides greater hardness, wear resistance, and fracture toughness. 20Cr steel was also found to possess similar strain-life properties to Q235 steel. These superior properties make 20Cr steel an ideal choice for applications that require high strength and wear resistance.

Microstructure of 20Cr Steel and Q235 Steel After Carburizing and Tempering

20Cr Steel and Q235 Steel are commonly used alloy materials among all kinds of steel. In order to meet the requirements of product performance and service life, 20Cr steel and Q235 steel are usually carried out carburizing and tempering treatment. Through carburizing and tempering, the parts have better mechanical properties, wear resistance, corrosion resistance and fatigue strength. The microstructure after carburizing and tempering treatment of 20Cr steel and Q235 steel is analyzed.

When 20Cr steel and Q235 steel are subjected to carburizing and tempering treatment, they become a microstructure composed of martensite, pearlite and carbides, as shown in the figure. In the microstructure, there are a large number of distributed carbides which are dispersed in the carbides and pearlite. The carburizing and tempering process makes the surface layer of the steel parts harden and strengthen due to the high hardenability of the carbon added during carburizing, while the part core can alleviate the stress caused by the surface hardening through tempering.

In the microstructure of 20Cr steel and Q235 steel after carburizing and tempering, these un-dissolved carbides play a very important role in ensuring the wear resistance, fatigue strength and corrosion resistance of steel parts. The carbides are able to effectively resist the wear of the parts and enhance their fatigue strength and corrosion resistance. As a result of its higher hardness, wear resistance and other excellent mechanical properties, 20Cr steel and Q235 steel are widely used in various engineering fields such as automobile manufacturing and manufacturing of electrical appliances.