Not quite equivalent, but see page 2946 at
ASTM A193 Grade B8 Heavy Hex Head
Made of 18-8 stainless steel. Great for bolting pressure vessels, valves, flanges, and fittings. Rockwell hardness is B96. Minimum tensile strength: 75,000 psi. Length is measured from under head. Made in the USA.
This isn’t quite stainless, but surely more corrosion resistant than plain steel A325:
ASTM A193 Grade B7 Hex Head
Made of chromium-molybdenum alloy steel. Ideal for bolting pressure vessels, valves, flanges, and fittings. Rockwell hardness is C28-C32. Tensile strength: 125,000 psi. Length ismeasured from under head. Made in the USA.
Cf page 2945:
ASTM A325 Heavy Hex Head
All bolts conform to ASTM A325 Type 1 for structural steel joints. Length is measured from under head. Rockwell hardness is C24-C35. For bolts 1/2_ through 1_ diameter, minimum tensile strength is 120,000 psi. For 11/8_ and 11/4_ diameter bolts, minimum tensile strength is 105,000 psi. Manufacturer and grade marked on top of head. Made in the USA or Canada.
Possibly of interest, on p. 2951
Ultra-Coated Grade 8 High-Strength Hex Head
A water-based inorganic coating, also known as armor coat, is applied to steel fasteners to provide better corrosion resistance than comparable hot dipped galvanized fasteners, and does not affect function of the thread. In addition, these screws are often effective replacements for stainless steel cap screws. Salt spray resistance of 1000 hours per ASTM B117. Screws meet SAE J429. Rockwell hardness is C33-39 with a minimum tensile strength of 150,000 psi. Made of medium-carbon alloy steel that has been quenched and tempered. Screws are grade marked on top of head (six radial lines indicate Grade 8). Length is measured from under head. Screw has a clear-silver finish. For ultra-coated nuts see 93827A on page 2990; for washers, see 98180A on page 3017. Made in North America.