Resistance Welding Coolant Flow & Line Sizing Calculator

Estimate total coolant flow, line velocity, and pressure-drop risk for a resistance welding cooling circuit. This page is meant as a practical starting point for weld guns, transformers, secondary cables, holders, and similar water-cooled components.

This works best for concept sizing, troubleshooting, and retrofit checks. Actual delivered flow still depends on manifold design, quick disconnects, internal passages, coolant temperature, branch balance, and OEM requirements.

Cooling Load Inputs

Primary Cooled Component Number of Devices / Branches Target Flow per Device (GPM) Simultaneous Use Factor Safety Factor Coolant Type

Line / Pressure Inputs

Main Supply Line ID Equivalent Total Line Length (ft) Available Supply Pressure (psi) Allowable Pressure Drop (psi) Fittings / Restriction Multiplier Preferred Max Velocity (ft/s)

Results

Base Total Flow

0.00 GPM

Recommended Total Flow

0.00 GPM

Line Velocity

0.00 ft/s

Estimated Pressure Drop

0.00 psi

Pressure Margin

0.00 psi

Suggested Minimum Line Size

What this tool is actually doing

This calculator totals your target device flow, applies a simultaneity factor, adds a safety factor, and then checks whether the selected line size looks reasonable. It estimates line velocity directly from flow and line ID, then uses a simplified pressure-drop model to flag circuits that look undersized.

It is intentionally built as a practical screening tool, not as an OEM-certified thermal model.

Why coolant flow matters in resistance welding

Low flow can increase heat in transformers, cables, holders, and gun components.
Undersized lines can create high velocity and unnecessary pressure loss.
Long runs, quick disconnects, elbows, and small internal passages all reduce delivered flow.
Parallel branches may still give uneven cooling if one path is more restrictive than the others.

Good practice: use this page to screen the circuit, then verify actual delivered flow at the machine whenever possible. A system can look acceptable on paper and still underperform because of branch imbalance or internal restrictions.

Related Welding Tools

Cooling ties directly into weld consistency, tip life, and thermal stability.

Resistance Spot Weld Calculator Projection Weld Calculator

Need help with a real weld system?

If you are trying to size a new cooling loop, fix hot weld cables, troubleshoot inconsistent temperature, or check whether a weld circuit is being starved, you can reach out for help on a real machine.

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