4Cr10Si2Mo steel (quenched and tempered) non-metallic inclusions

Nonmetal Inclusions in 4Cr10Si2Mo Steel (Heat Treatment)

Introduction

4Cr10Si2Mo steel is an alloy that is widely used in the industry due to its outstanding properties such as high strength, good wear resistance and good corrosion resistance. As with any steel product, during production it is important to ensure that the steel is free from nonmetal inclusions. Nonmetal inclusions such as oxides, sulfides and silicates can have a detrimental effect on steel properties. Therefore, it is important to understand the nature and behavior of nonmetal inclusions in 4Cr10Si2Mo steel and how to achieve optimum results during heat-treatment.

Chemical Composition of 4Cr10Si2Mo Steel

The 4Cr10Si2Mo steel is an iron-based alloy containing good amounts of chromium, molybdenum and silicon. The maximum percentage composition of 4Cr10Si2Mo steel is presented in Table 1.

Table 1 Maximum Percentage Composition of 4Cr10Si2Mo Steel (Heat Treatment)

Carbon (C) 0.25-0.35

Manganese (Mn) 0.50-1.0

Chromium (Cr) 4.0-5.0

Silicon (Si) 2.0-3.0

Molybdenum (Mo) 1.0-2.0

Sulfur (S) 0.030 max

Phosphorus (P) 0.035 max

Copper (Cu) 0.20 max

Total dissolved inclusions 0.040 max

Nonmetal Inclusions in 4Cr10Si2Mo Steel

Nonmetal inclusions in 4Cr10Si2Mo steel are formed during the casting and rolling processes. Due to their thermodynamic behavior the most commonly found nonmetal inclusions in 4Cr10Si2Mo steel are oxides, sulfides and silicates. These vary in size and shape and can have a negative effect on the properties of the steel.

Inclusions can be divided into two main categories which are surface inclusions and internal inclusions. Surface inclusions are usually present on the surface of the steel while internal inclusions are located inside of the steel. Nonmetal inclusions can also be further separated into primary and secondary. Primary inclusions are those which have been formed during the melting process and have not undergone any reaction. Secondary inclusions are those which have become inclusions after being exposed to a reaction.

Heat Treatment of 4Cr10Si2Mo Steel

Heat treatment is an important process used to improve the mechanical and physical properties of 4Cr10Si2Mo steel. Heat treatment is used to adjust the steel microstructure by either raising or lowering the temperature, at which the steel is being processed.During heat treatment it is important to ensure that the steel is free from any nonmetal inclusion. In order to remove the nonmetal inclusions, the steel should be homogenized before starting the heat treatment process. By homogenizing the steel, the inclusions will move and concentrate towards the surface of the steel, making them easier to remove. The removal of nonmetal inclusions can be done manually by grinding or by using a chemical method.

Conclusion

This article has discussed the nonmetal inclusions that can be found in 4Cr10Si2Mo steel and how to effectively remove these inclusions before heat treatment. It is important to understand the nature and behavior of nonmetal inclusions during production and to ensure that the steel is free from them in order to obtain the desired properties of 4Cr10Si2Mo steel. Heat treatment can be used to improve the mechanical and physical properties of the steel, thereby improving the performance of the product.

4Cr10Si2Mo Steel (Tempering Treatment)

4Cr10Si2Mo steel, also known as 4Cr10Si2MoA steel, is a low-alloy martensitic steel with good wear resistance and fair corrosion resistance. It is generally used in the tempering treatment process after quenching, which can be used in the form of annealing and quenching.

4Cr10Si2Mo steel can be used to make various parts, such as pump valves, wear-resistant mechanical parts, pipeline valves, etc. It contains core elements chromium, silica and molybdenum, but does not contain any non-metallic inclusions. The chromium content of 4Cr10Si2Mo steel is usually between 0.18~0.22%, the silica content is usually between 0.90~1.20%, and the molybdenum content is usually between 0.50~0.60%. The chemical composition of the quenched and tempered 4Cr10Si2Mo steel is characterized by its high strength, but also by good plasticity, toughness and weldability.

When tempered, the yield strength of 4Cr10Si2Mo steel increases significantly. This is due to the further reduction in thermal stress sigma and the disappearance of residual stress sigma2, the economy of tempering personnel, and the decrease of temperment efficiency. The hardness of the tempered 4Cr10Si2Mo steel is proportional to the tempering temperature, and the higher the tempering temperature is, the higher the hardness is. The higher the tempering temperature is, the lower the micro-hardness of the martensite is.

In addition, 4Cr10Si2Mo steel parts should also be protected before tempering. Although the impact strength and plasticity of 4Cr10Si2Mo steel are improved after tempering, the corrosion resistance of 4Cr10Si2Mo steel is reduced and the mechanical properties are affected. Therefore, it is necessary to carry out the corrosion protection of 4Cr10Si2Mo steel parts before tempering.

In conclusion, 4Cr10Si2Mo steel is low alloy martensitic steel which is tempered for good wear resistance and fair corrosion resistance. After tempering, the yield strength of 4Cr10Si2Mo steel increases greatly and its hardness is proportional to the tempering temperature. In order to reduce the effect on its mechanical properties, the corrosion protection of 4Cr10Si2Mo steel parts should be carried out before tempering.