Coast Guard Exams
Question 216General Subjects - Assistant Engineer70% to pass

When hardened metal is heat-treated by a process known as tempering, what metallurgical properties are achieved?

AI Explanation
The correct answer is A) decrease in brittleness. Tempering is a heat treatment process applied to hardened metal to decrease its brittleness and increase its toughness. The tempering process involves heating the hardened metal to a specific temperature, holding it at that temperature for a certain time, and then allowing it to cool. This process relieves the internal stresses in the metal, resulting in a decrease in its brittleness and an increase in its ductility and impact resistance. The other options are incorrect because: B) increase in hardening is not the result of tempering, which is intended to reduce hardness; C) increase in brittleness is the opposite of what tempering achieves; and D) increase in corrosion resistance is not a primary effect of the tempering process.