API 571 Certification (Corrosion & Materials) Practice Test

The correct choice indicates that C-0.5Mo and 1.25Cr carbon steel types are not heavily influenced by temper embrittlement because these steel grades generally have lower sensitivity to this phenomenon compared to other types. Temper embrittlement is a form of embrittlement that can occur in certain steel grades, particularly those alloyed with molybdenum, boron, or chromium, which can segregate impurities during the heat treatment process.

C-0.5Mo and 1.25Cr steels are typically designed with specific alloying elements that enhance their mechanical properties without making them overly susceptible to the embrittling effects associated with tempering at high temperatures. Their chemical composition plays a significant role in mitigating temper embrittlement, allowing them to retain toughness and ductility, especially compared to other carbon and alloy steels.

In contrast, options involving different compositions, such as Cr and Boron steels, can exhibit more pronounced temper embrittlement due to their specific alloying elements and their effects during the heat treatment process. High carbon steels, besides, may also be affected under certain conditions due to carbon's significant influence on the properties of steel during tempering.