US Customary Heat Input from Weld Leg Size Calculator

The US Customary Heat Input from Weld Leg Size Calculator predicts the amount of heat or thermal energy that is introduced to a material based on the typically accurate relationship between heat input and the rounded fillet weld size.

INSTRUCTIONS: Choose units and enter the following:

• (`ω`) Leg Size (inches)

Heat Input (`H`) : The calculator returns the answer in kJ/in. However this can be automatically converted to compatible units via the pull-down menu.

To find the heat input with metric units, try: Metric Heat Input from Weld Leg Size Calculator

The Math / Science

Arc voltage, current, and travel speed directly affect heat input. Heat input is often associated with cooling rates of the heat-affected zone and the weld. Heat input is also directly proportional to the individual weld bead cross-sectional size. For example, the size of a fillet weld increases as the heat input increases. 

To find the heat input, use the formula:

H = 500ω²

where:

`H` = heat input

`ω` = weld leg size

Welding Calculators and Constants

• Bend Allowance Calculator
• Weight of Aluminum Square Bars
• Steel Wire Deposition Rate Calculator
• Welding Heat Input Calculator
• Groove Weld Potential Root Cracking Calculator
• Weight of Hot Rolled Steel Flats
• Modulus of Elasticity for Martensitic Stainless Steel
• Brinell Hardness of Gray Cast Iron

References

Tools for Reviewing Welding Procedures (https://app.aws.org/mwf/attachments/11/253611/TOOLSFORREVIEWINGWELDINGPROCEDURES.pdf)

Bridge Welding Reference Manual (https://www.fhwa.dot.gov/bridge/steel/pubs/hif19088.pdf)