What is the composition features of Q420 alloy

Q420 material is a low alloy steel. Let's have a brief introduction for its composition features.
(1) Low carbon: Due to the high requirements for toughness, weldability and cold forming performance, its carbon content does not exceed 0.20%.
(2) Add alloy elements mainly containing manganese.
(3)Add auxiliary elements such as niobium, titanium or vanadium: a small amount of niobium, titanium or vanadium forms fine carbides or carbonitrides in the steel, which is beneficial to obtain fine ferrite grains and improve the strength and toughness of the steel . In addition, adding a small amount of copper (≤0.4%) and phosphorus (about 0.1%), etc., can improve the corrosion resistance. 
(4)The addition of a small amount of rare earth elements can desulfurize, degas, and alloy plates to purify steel and improve toughness and process performance.

Heat treatment characteristics for Q420 alloy: This type of steel is generally used in the state of hot rolling and air cooling, and no special heat treatment is required. The microstructure in use is generally ferrite + sorbite.

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