Which unit combination is used to express porosity limits in the PQ weld criteria?

Which unit combination is used to express porosity limits in the PQ weld criteria?

• A. Inches are used for all measurements
• B. Millimeters for porosity and weld length (with inch equivalents in parentheses)
• C. Centimeters for all measurements
• D. Meters for all measurements

Answer: (B)

PQ weld criteria specify porosity limits using millimeters for both the porosity size and the weld length, with inch equivalents shown in parentheses. This keeps the defect measurements precise and consistent with metric-based engineering standards, while still offering familiar inch values for those who read specifications in imperial units. Millimeters provide the necessary granularity for small porosity features, which is essential for accurately assessing weld quality. Using centimeters or meters would be too coarse for typical porosity limits, and relying only on inches would reduce precision and complicate conversions, so the metric-first approach with optional inch references is the most practical choice.

PQ weld criteria specify porosity limits using millimeters for both the porosity size and the weld length, with inch equivalents shown in parentheses. This keeps the defect measurements precise and consistent with metric-based engineering standards, while still offering familiar inch values for those who read specifications in imperial units. Millimeters provide the necessary granularity for small porosity features, which is essential for accurately assessing weld quality. Using centimeters or meters would be too coarse for typical porosity limits, and relying only on inches would reduce precision and complicate conversions, so the metric-first approach with optional inch references is the most practical choice.