Quenched-and-tempered alloy steel — Grades BC and BD, with BD comparable to SAE Grade 8.
ASTM A354 covers quenched-and-tempered alloy-steel bolts, studs, and other externally threaded fasteners 4″ and under in diameter. It's offered at two strength levels — Grade BC and the higher-strength Grade BD — and is unrestricted in configuration, so it can be a headed bolt, bent bolt, or threaded rod.
Grade BD is equal in strength to A490 (ASTM F3125), and broadly comparable to SAE Grade 8 — but unlike A490, A354 isn't limited to structural use or to 1-1/2″ and under. That makes BD the go-to for anchor bolts, threaded rods, and larger-diameter high-strength work. Grade BC is a step down, often specified in place of A325 where configuration or size rules A325 out.
A354 heads carry the manufacturer's identification symbol and the marking “A354” together with the grade (BC or BD). Like the other ASTM grades, it's identified by its stamped designation rather than the SAE radial-line system — even though Grade BD matches Grade 8 in strength.
| Grade | Size Range | Tensile, min | Yield, min | Elong, min | RA, min | Hardness |
|---|---|---|---|---|---|---|
| Grade BC | 1/4″ thru 2-1/2″ | 125,000 psi | 109,000 psi | 16% | 50% | 26–36 HRC |
| Over 2-3/4″ thru 4″ | 115,000 psi | 99,000 psi | 16% | 45% | 22–33 HRC | |
| Grade BD | 1/4″ thru 4″ | 150,000–173,000 psi | 130,000 psi | 14% | 40% | 33–38 HRC |
Grade BD carries a tensile range (a ceiling as well as a floor). For BD over 2-1/4″, the standard adds a Charpy impact requirement (20 ft-lb min at −4°F) and cross-sectional hardness testing.
| Element | Grade BC (all) & BD ≤ 2-1/4″ | Grade BD over 2-1/4″ |
|---|---|---|
| Carbon | 0.30–0.53% | 0.35–0.53% |
| Manganese, min | 0.60% | 0.60% |
| Phosphorus, max | 0.035% | 0.035% |
| Sulfur, max | 0.040% | 0.040% |
| Boron, max | 0.003% | 0.003% |
| Nickel, min | — | 0.40% |
| Chromium, min | — | 0.40% |
| Molybdenum, min | — | 0.15% |
Larger-diameter BD fasteners require the added alloying elements (Ni, Cr, Mo) to develop full strength through the section.
| Grade | Finish | Nut | Washer |
|---|---|---|---|
| Grade BC | Plain | ASTM A563 Grade C heavy hex | ASTM F436 |
| Galvanized | ASTM A563 DH heavy hex | ||
| Grade BD | All finishes | ASTM A563 DH heavy hex |
Nuts of other grades and styles with proof-load stresses greater than the specified nut are also acceptable.