Do A325-3 and A490-3 bolts rust?
Yes, A325-3 and A490-3 are made from weathering steel containing copper, chromium, and nickel which induces the surface to form a heavy oxide coating that protects the base material from corroding any further. This brownish-red coating seals the material from corrosion much like other external coating options. These types of bolts are more often used in more temperate climates, unlike the Northwest where hot-dip galvanizing is more prevalent. Accessibility of these bolts may be limited due to material availability especially in ½” diameter.