The Brinell hardness number is related to the proportional limit and the ultimate tensile strength of dental gold alloys. Because the test is a relatively simple one, it may often be conveniently used as an index of properties that involve more complex test methods. The Brinell hardness test is one of the oldest tests employed for determining the hardness of metals. Key Concept: The Brinell hardness number is related to the proportional limit and the ultimate tensile strength of dental gold alloys. Phillips dental materials 12th edition page no 64