What is the effect of carbon equivalent on steel plate

Carbon equivalent refers to the conversion of the effect of various alloying elements in steel on the actual carbon content of the eutectic point into the increase or decrease of carbon.

Carbon equivalent empirical formula for carbon steel and alloy structural steel:
C equivalent=[C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15]*100%
In the formula: C, Mn, Cr, Mo, V, Ni, Cu are the content of this element in the steel.

The carbon equivalent Ceq (percent) value can be calculated by the following formula:
Ceq=C+Mn/6+(Cr+V+Mo)/5+(Cu+Ni)/15
(The allowable deviation of carbon equivalent Ceq is +0.03%)

The carbon equivalent CE formula of the International Institute of Welding (IIW)
CE= [W(c) +W(Mn)/6+[W(Cr)+W(Mo)+W(V) ]/5+[W(Ni)+W(Cu)]/15

Ce (carbon equivalent) evaluation of weldability
The effect of carbon equivalent on steel plate
CE≤0.4% good weldability;
When CE=0.4-0.6%, the weldability is slightly poor, and proper preheating is required before welding;
When CE≥0.6%, the weldability is poor, it is a difficult-to-weld material, and a higher preheating temperature and strict process methods are required;
Oxygen, hydrogen, nitrogen, sulfur and phosphorus in steel are harmful elements, which also affect welding performance.