Can I get A325 bolts in stainless steel?

The short answer is, “No, you cannot match the A325 strength with stainless steel.” Some grades of strain hardened or quenched and tempered stainless steel fasteners will exceed the A325 strength requirements, but most standard stainless fasteners are not nearly as strong as A325 bolts.  These bolts are very different chemically.  Whereas stainless steels consist of chrome and nickel, A325 bolts have a chemical composition of medium carbon or medium carbon alloy steel that is quenched and tempered.  Stainless steel is naturally corrosion-resistant.  However, for an A325 bolt to be corrosion-resistant , one would need to move to a hot-dip galvanized finish or the type 3 (weathering steel) version of the A325 specification.

The other major difference is in the thread length. A325 bolts have a reduced thread length to keep the threads out of the shear plane. Stainless steel bolts will have standard thread lengths. Another difference could be the head type. A325 calls for a heavy hex head (unless otherwise specified), whereas F593 stainless steel bolts have a standard hex head. A193 stainless steel bolts will have a heavy hex head.  A325 bolts also require a full body diameter due to their structural application, while stainless steel bolts can be manufactured with a reduced body diameter and rolled threads.

Grade Diameter Tensile min psi Yield min psi Elongation min % Red of Area min %
A325 1/2" thru 1-1/2" 120,000 92,000 14 35
A193 class 1 1/2" thru 1-1/2" 75,000 30,000 30 50
A193 B8 class 2 1/2" thru 3/4" 125,000 100,000 12 35
7/8" thru 1" 115,000 80,000 15 35
1-1/8" thru 1-1/4 105,000 65,000 20 35
1-3/8" thru 1-1/2" 100,000 50,000 28 45
A193 B8M class 2 1/2" thru 3/4" 110,000 95,000 15 45
7/8" thru 1" 100,000 80,000 20 45
1-1/8" thru 1-1/4 95,000 65,000 25 45
1-3/8" thru 1-1/2" 90,000 50,000 30 45
F593 CW 304/316 1/2" thru 5/8" 120000-160,000 95,000 95 no minimum
3/4" thru 1" 110000-150,000 75,000 75 no minimum
1-1/8" thru 1-1/4" 100000-140,000 60,000 60 no minimum
1-3/8" thru 1-1/2"   95000-130,000 45,000 45 no minimum
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