A bolt with a single raised dash on the head belongs to which AN bolt class?

• A. AN corrosion-resistant steel bolt
• B. AN high-strength bolt
• C. AN aluminum bolt
• D. AN stainless bolt

Answer: (A)

The marking on the head of an AN bolt is a key way to identify its material class. In this system, a single raised dash on the bolt head is used to designate corrosion-resistant steel bolts. That small mark helps maintenance technicians quickly select the right fastener for environments where corrosion resistance is important, without needing to inspect the entire part number. Other material classes, such as aluminum or stainless bolts, use different head markings, so a bolt with just one raised dash would not fall into those categories. The emphasis here is on material compatibility and corrosion resistance, which is why a single dash points to corrosion-resistant steel.