API 571 Certification (Corrosion & Materials) Practice Test

Which metal or alloy is most susceptible to thermal fatigue or shock?

1. High Nickel Cast Iron

2. 316L SS

3. All metals and alloys

4. Alloy C-276

The correct answer is: All metals and alloys

Thermal fatigue, also known as thermal shock, occurs when there are rapid changes in temperature that create stress within a material due to differential expansion or contraction. All metals and alloys can experience thermal fatigue under certain conditions, especially when subjected to extreme temperature variations or rapid temperature changes during operation. In the context of materials used in various engineering applications, while some specific metals and alloys such as high nickel cast iron, 316L stainless steel, and Alloy C-276 might exhibit greater resilience or specific susceptibility to thermal fatigue, the statement that all metals and alloys can experience this phenomenon captures the broader truth. Materials will respond differently based on their thermal expansion coefficients, mechanical strength, ductility, and service conditions; hence, while some might be more prone under certain scenarios, none are completely immune to thermal fatigue, particularly under harsh thermal cycling conditions. Thus, recognizing that all metals and alloys are capable of facing thermal fatigue or shock under appropriate mechanical and thermal loading leads to a comprehensive understanding of material behavior in dynamic environments.