The imperial standard is officially titled Standard Specification for Structural Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile Strength, while the metric standard (M) is titled Standard Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints.
A325 and A490 heavy hex structural bolts are now grades under the new F3125 specification.
[3] There are also three connection types defined:[4] These bolts are equivalent to ASTM A325 bolts in application and geometry, but are made to a higher strength.
The metric grades are made to the same strength specifications as ASTM F568M property class 10.9.
[5] Also, unlike their weaker counterparts they may not be coated by hot-dip galvanization, mechanical deposition, or electroplating.