Heat input in welding depends on which factors?

• A. Ambient temperature
• B. Welding torch angle
• C. Voltage, current, and arc time
• D. Color of electrode

Answer: (C)

Heat input is the energy the welding arc delivers to the weld area, and it comes from the arc’s electrical power and how long the arc is on. The power delivered by the arc equals voltage times current, and the total energy depends on how long that current flows (arc time). So increasing voltage, increasing current, or keeping the arc on longer all raise the heat input. Ambient temperature, the torch angle, or the color of the electrode don’t change the amount of energy the arc delivers, though torch angle can influence penetration and bead shape. Therefore, the factors that determine heat input are voltage, current, and arc time.