How are AN standard steel bolts identified?

AN standard steel bolts are identified by the code markings on the bolt heads. These markings provide crucial information about the bolt's material, strength, and design features. The codes consist of a series of letters and numbers that convey specific properties according to established standards for aviation hardware. This identification method ensures that mechanics can accurately select bolts that meet the necessary specifications for various applications, ensuring safety and reliability in aircraft construction and maintenance.

In contrast, other methods of identification such as color, strength rating, or size and shape do not provide the standardized, universally understood information necessary for properly identifying bolts used in aviation. While size and shape can be generally useful, they do not communicate vital details regarding the material properties or specific applications of the bolt.