Why may preheating a steel plate with a carbon equivalent (CEV) of 0.48 be required?

The correct answer is option B.

Preheating the steel plate to be welded slows the cooling rate in the weld area. This helps prevent cracking or shrinking of the weld metal or heat affected zone. The thicker the steel, the more important it is to preheat it. The CEV refers to the equivalent carbon content of the steel, which in this case is 0.48, it refers to the method of measuring the maximum hardness and the weldability based on its chemical composition.

For good welding result, CEV is expected not to exceed o.45. Since this steel has a CEV of 0.48, it should be preheated to prevent hydrogen induced cold cracking and hardening in the heat affected zone.

The correct answer to this question is B. Preheating prevents excessive hardness in the HAZ (heat-affected zone) of a steel plate., making it easier to work with. A piece of steel with a CEV (equivalent carbon content) higher than 0.40 is prone to cracking, shrinking, and distortion if it is not preheated.

Welding is the act of joining together pieces of metal by heating and melting the surfaces with a blowtorch or electric arc and uniting them by pressing or hammering. Technical schools offer welding training and certification, and a welding career can be quite lucrative.