The method
Before using the result
- Steady representative voltage/current and travel speed. Pulsed waveform power must be measured appropriately; average V × average I may not equal average power. No WPS qualification judgement.
Worked examples
These original training examples illustrate the method for Certified Welding Inspector (CWI). Use the matching “Load example” button above to explore a variation; example values are not equipment settings or prescribed criteria.
1. Worked example
Distinguish electrical arc energy from efficiency-adjusted heat input in a welding-inspection calculation. Check travel-speed units before comparing procedure values.
- Arc voltage (V)
- 24
- Welding current (A)
- 200
- Travel speed
- 300 mm/min
- Include supplied thermal efficiency
- No
- Arc energy = 24 × 200 / 0.005 = 960000 J/m.
- 1 kJ/mm = 1,000,000 J/m.
- Thermal efficiency was not supplied; net heat input is not reported.
- Arc energy: 0.96 kJ/mm
2. Comparison example
Compare a different supplied condition using the same method. For Welding Exam, the important check is that the input meaning, units and method assumptions still match the problem.
- Arc voltage (V)
- 24
- Welding current (A)
- 200
- Travel speed
- 240 mm/min
- Include supplied thermal efficiency
- No
- Arc energy = 24 × 200 / 0.004 = 1200000 J/m.
- 1 kJ/mm = 1,000,000 J/m.
- Thermal efficiency was not supplied; net heat input is not reported.
- Arc energy: 1.2 kJ/mm
Check your understanding
1. Which relationship is used?
Arc energy/length = voltage × current / travel speed; net heat input = arc energy × supplied thermal efficiency.
2. Which assumption should you check first?
Steady representative voltage/current and travel speed. Pulsed waveform power must be measured appropriately; average V × average I may not equal average power. No WPS qualification judgement.
3. How should you verify a different unit system?
Convert every input to the displayed calculation units first. Equivalent physical inputs must give equivalent results; a unit label alone does not convert a number.
Continue with the matching exam topic
This tool connects to Certified Welding Inspector (CWI) free practice. Work through a question independently, then use the calculation steps to identify where your method differs. The tool stays free whether or not you choose paid preparation.