How to calculate heat input from welding?

# Heat Input Caculation

**Heat Input = (60 x Amps x Volts) / (1,000 x Travel Speed in in/min) = KJ/in**

or

The 60 and the 1,000 are there to turn the final answers into Kilojoules per inch.

Example: You are welding at 500 inches per minute and 29 volts. Your weld is 25 inches long and it takes the welder 2 minutes to weld it. While he is welding, you notice the machine is displaying an amperage of 325.

What is your heat input?

Before calculating heat input you need to determine your travel speed.

**Travel Speed** = Length of Weld / Time to weld = 25 inches / 2 minutes = 12.5 inches per minute

**Heat Input** = [(60 sec/min) x (325 amps) x (29 volts)] / [(1,000 joules/kilojoule) x (12.5 inches/minute)]

= 45.24 KJ/in

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