Final answer:
The correct test for assessing the resistance of steel to failure by brittle fracture is the notched bar impact test. This reveals the material's toughness and energy absorption before fracturing, which is essential for applications where steel might face sudden stresses or be in cold environments.
Step-by-step explanation:
The resistance of steel to failure by brittle fracture is commonly assessed by conducting a notched bar impact test. This type of test evaluates the material's toughness and its ability to absorb energy before fracturing. It is a crucial test for materials like steel that could be exposed to sudden stresses or low temperatures, where brittle fracture might occur.
A tensile test measures the material's tensile strength, which is the breaking stress that can cause permanent deformation or fracture. On a stress-strain graph, ending at the fracture point, the ultimate stress, also known as breaking stress, is illustrated. For steel and aluminum rods with a 1-in² cross-sectional area, their breaking loads can significantly differ, showcasing the variance in breaking stress and the material's overall strength.
While tests like the Rockwell C hardness test and chemical analysis provide other important information about a material's properties, they do not directly assess the resistance to brittle fracture as the notched bar impact test does. Similarly, the hydrogen embrittlement test is specific to evaluating the effects of hydrogen absorption in metals, which can also lead to embrittlement.