The method
Before using the result
- Uniform temperature change, constant user-supplied coefficient and free unrestrained expansion. Restraint stresses are not calculated.
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
Explain the direction of free thermal movement in a fabrication example. Do not infer weld shrinkage, residual stress or restraint force from a simple expansion result.
- Original length
- 10 m
- Linear expansion coefficient (1/K)
- 0.000012
- Temperature change
- 50 K
- ΔL = 0.000012 × 10 × 50 = 0.006 m.
- Length change: 0.006 m
- Final length: 10.006 m
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.
- Original length
- 10 m
- Linear expansion coefficient (1/K)
- 0.000012
- Temperature change
- -30 K
- ΔL = 0.000012 × 10 × -30 = -0.0036 m.
- Length change: -0.0036 m
- Final length: 9.9964 m
Check your understanding
1. Which relationship is used?
ΔL = αLΔT; final length = original length + ΔL.
2. Which assumption should you check first?
Uniform temperature change, constant user-supplied coefficient and free unrestrained expansion. Restraint stresses are not calculated.
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.