Why must metal that is below 70°F (20°C) be preheated before welding?
A) If the metal is too cold, you cannot get a weld pool established.
B) Because the cold metal quenches the weld.
C) The arc on cold metal is not stable, and it will wander around the surface making it hard to keep the weld going along the joint.
D) The hot metal on the cold plate will not stick, it just bounces off.

Question

Quizplus · Accepted Answer

Preheating metal that is below 70°F (20°C) is necessary because the cold metal can quench the weld, leading to rapid cooling and potential issues like cracking or poor fusion.

Why Must Metal That Is Below 70°F (20°C) Be Preheated