Metric Fillet Weld Leg Size from Heat Input Calculator

The Metric Fillet Weld Leg Size from Heat Input Calculator uses the amount of heat or thermal energy that is introduced to a material and the typically accurate relationship between heat input and rounded fillet weld size to find the predicted leg size.

INSTRUCTIONS: Choose units and enter the following:

• (`H`) Heat Input (kJ/mm)

Leg Size (`ω`): The calculator returns the answer in millimeters. However this can be automatically converted to compatible units via the pull-down menu.

To find the weld leg size with imperial units, try: US Customary Fillet Weld Leg Size from Heat Input 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 leg size, use the formula:

ω =  5.5 ⋅ √ H

where:

`ω` = weld leg size

`H` = heat input

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)