Which of the following is a true interpretation of the suffix 30 in the 1030 aluminum designation?

Which of the following is a true interpretation of the suffix 30 in the 1030 aluminum designation?

• A. It indicates 99.30% purity
• B. It indicates 30% strength
• C. It indicates 30% density
• D. It indicates 3.0% stress limit

Answer: (A)

In this aluminum designation, the 1xxx series means commercially pure aluminum, and the two digits at the end show the minimum aluminum content. The suffix 30 means the alloy has at least 99.30% aluminum by mass. So the designation 1030 indicates a purity of 99.30%. This suffix isn’t about strength, density, or stress limits—those properties depend on the alloy’s overall composition and temper, not this purity code. For example, other 1xxx designations follow the same pattern, with the final digits indicating the minimum percent Al, such as 1050 being at least 99.50% Al.

In this aluminum designation, the 1xxx series means commercially pure aluminum, and the two digits at the end show the minimum aluminum content. The suffix 30 means the alloy has at least 99.30% aluminum by mass. So the designation 1030 indicates a purity of 99.30%. This suffix isn’t about strength, density, or stress limits—those properties depend on the alloy’s overall composition and temper, not this purity code. For example, other 1xxx designations follow the same pattern, with the final digits indicating the minimum percent Al, such as 1050 being at least 99.50% Al.