The influence of alloying elements on steel properties

    The elements intentionally added during the smelting process to improve and enhance the properties of steel and to obtain certain special properties are called alloying elements. Commonly used alloying elements include chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, silicon, manganese, aluminum and rare earth. This article will share with you the important role of common alloying elements in steel casting.

01 Cr (Cr)

Chromium is the main alloying element of stainless acid-resistant steel and heat-resistant steel

Chromium can improve the strength and hardness of steel

Chromium can improve the high-temperature mechanical properties of steel

Make steel have good corrosion resistance and oxidation resistance

Reduce the critical cooling rate of steel and improve the hardenability of steel

Prevent graphitization

02 Ni (Nickel)

Nickel is one of the important elements in stainless acid-resistant steel

Nickel can reduce the brittle transition temperature of steel, that is, improve the low-temperature toughness of steel

Improve the processability and weldability of steel

Nickel can improve the corrosion resistance of steel, not only acid-resistant, but also alkali and atmospheric corrosion

03 Mo (Molybdenum)

Molybdenum has a solid solution strengthening effect on ferrite, improving the strength and hardness of steel

Improve the heat resistance and high-temperature strength of steel

Anti-hydrogen corrosion effect

Reduce the critical cooling rate of steel and improve the hardenability of steel

04 W (Tungsten)

Increase strength Improve the high temperature strength of steel. Improve the hydrogen resistance of steel. It makes steel hot hard, so tungsten is the main alloying element in high-speed tool steel.

05 V (vanadium)

Improve the heat resistance. Refine the structure and grain of steel, reduce the strength and toughness of steel. Vanadium can significantly improve the welding performance of ordinary low-carbon low-alloy steel.

06 Ti (titanium)

Titanium is one of the important alloying elements in the heat-resistant steel used for high-temperature components of boilers. Titanium can improve the heat resistance of steel, improve the creep resistance and high-temperature endurance strength of steel. It can improve the stability of steel in high-temperature and high-pressure hydrogen. Makes steel stable to hydrogen at high pressures up to 600°C or more. In pearlite low alloy steel, titanium can prevent molybdenum steel from graphitizing at high temperatures.

07 Mn (Manganese)

In low content range, it has a great strengthening effect on steel, improving strength, hardness and wear resistance

Reduces the critical cooling rate of steel and improves the hardenability of steel

Slightly improves the low temperature toughness of steel

In high content range, as the main austenitizing element

Manganese has a significant effect on improving the strength of low carbon and medium carbon pearlite steels

Manganese improves the instantaneous strength of steel at high temperatures

08 Si (Silicon)

Main alloying element in magnetic steel (when the content is within the range of 0.40%, it improves the tendency of hot cracking. When the content is high, it is easy to form columnar crystals and increase the tendency of hot cracking)

Increase the strength of the solid solution in steel and the degree of cold working hardening to reduce the toughness and plasticity of steel

Silicon can significantly improve the elastic limit, yield limit and yield strength ratio of steel, which is a general spring steel

Corrosion resistance, high silicon cast iron with a silicon mass fraction of 15% to 20% is a good acid-resistant material

Reduce the critical cooling rate of steel and improve the hardenability of steel

09 Al (aluminum)

Used as a deoxidation and nitrogen fixation agent in steelmaking, refines grains, inhibits the aging of low-carbon steel, improves the toughness of steel at low temperatures, and especially reduces the brittle transition temperature of steel;

Improve the oxidation resistance of steel

It can also improve the corrosion resistance to hydrogen sulfide and V2O5

10 Nb (niobium)

Niobium has a strong binding force with carbon, nitrogen and oxygen, and forms corresponding extremely stable compounds with them, so it can refine the grains and reduce the overheat sensitivity and temper brittleness of steel. It has excellent hydrogen resistance. Niobium can improve the thermal strength of steel.

11 RE (rhenium)

Generally known as the 17 elements of rare earth elements

The unseparated rare earth is called mixed rare earth, which is relatively cheap. Rare earth elements can improve the plasticity and impact toughness of forged steel, especially in cast steel

It can improve the creep resistance of heat-resistant steel electric heating alloys and high-temperature alloys

It can also improve the oxidation resistance and corrosion resistance of steel. The oxidation resistance effect exceeds that of silicon, aluminum, titanium and other elements. It can improve the fluidity of steel, reduce non-metallic inclusions, and make the steel structure dense and pure

Adding appropriate rare earth elements to ordinary low-alloy steel has good deoxidation and desulfurization effects, improves impact toughness (especially low-temperature toughness), and improves anisotropic properties