The carbon content of steel with an SAE code number of 8720 is approximately what percentage?

The correct answer is that the carbon content of steel with an SAE code number of 8720 is approximately 0.20 percent. The SAE (Society of Automotive Engineers) classification system provides a way to identify the chemical composition of steel and its properties. In this particular coding format, the first two digits indicate the primary alloying elements, while the last two digits represent the approximate carbon content as a percentage multiplied by 100.

In the case of 8720, the '20' at the end indicates that the carbon content is around 0.20 percent. It's important to note that the figures associated with these codes represent a range – thus, the exact carbon percentage can vary slightly depending on specific manufacturing practices and tolerances, but 0.20 percent is a standard approximation for this classification. Understanding this numbering and its implications is crucial for selecting the right steel for applications in engineering and construction, highlighting the importance of material properties in instrumentation and other fields.