What are the grades of steel bar stock?

Standard alloy numbering system for steel grades

The SAE steel grades system is a standard alloy numbering system (SAE J1086 - Numbering Metals and Alloys) for steel grades maintained by SAE International.

In the 1930s and 1940s, the American Iron and Steel Institute (AISI) and SAE were both involved in efforts to standardize such a numbering system for steels. These efforts were similar and overlapped significantly. For several decades the systems were united into a joint system designated the AISI/SAE steel grades. In 1995 the AISI turned over future maintenance of the system to SAE because the AISI never wrote any of the specifications.[1]

Today steel quotes and certifications commonly make reference to both SAE and AISI, not always with precise differentiation. For example, in the alloy/grade field, a certificate might refer to "4140", "AISI 4140", or "SAE 4140", and in most light-industrial applications any of the above is accepted as adequate, and considered equivalent, for the job at hand, as long as the specific specification called out by the designer (for example, "4140 bar per ASTM-A108" or "4140 bar per AMS 6349") is certified to on the certificate. The alloy number is simply a general classifier, whereas it is the specification itself that narrows down the steel to a very specific standard.

The SAE steel grade system's correspondence to other alloy numbering systems, such as the ASTM-SAE unified numbering system (UNS), can be seen in cross-referencing tables (including the ones given below).

The AISI system uses a letter prefix to denote the steelmaking process. The prefix "C" denotes open-hearth furnace, electric arc furnace or basic oxygen furnace steels, while "E" specifies only electric arc furnace steel. A letter "L" within the grade name indicates lead as an added ingredient; for example, 12L14 is a common grade that is 1214 with lead added for machinability.

Suffixes may be added to the steel grade which specify the forming process used to create a part. These may include cold working (CDS), hot working (HR), quenching and tempering (Q&T), and other methods.

Carbon steel

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Carbon steels and alloy steels are designated a four digit number, whereby the first digit indicates the main alloying element(s), the second digit indicates tg (top grade) element(s), and the last two digits indicate the amount of carbon, in hundredths of a percent (basis points) by weight. For example, a 1060 steel is a plain-carbon steel containing 0.60 wt% C.

An "H" suffix can be added to any designation to denote hardenability is a major requirement. The chemical requirements are loosened but hardness values defined for various distances on a Jominy test.

Carbon and alloy steel grades SAE designation Type, and composition by weight Carbon steels 10xx Plain carbon (Mn 1.00% max.) 11xx Resulfurized 12xx Resulfurized and rephosphorized 15xx Plain Carbon (Mn 1.00–1.65% max.) Manganese steels 13xx Mn 1.75% Nickel steels 23xx Ni 3.50% 25xx Ni 5.00% Nickel-chromium steels 31xx Ni 1.25%; Cr 0.65%, or 0.80% 32xx Ni 1.75%; Cr 1.07% 33xx Ni 3.50%; Cr 1.50%, or 1.57% 34xx Ni 3.00%; Cr 0.77% Molybdenum steels 40xx Mo 0.20%, 0.25%, or Mo 0.25% and S 0.042%[1] 44xx Mo 0.40%, or 0.52% Chromium-molybdenum (chromoly) steels 41xx Cr 0.50%, 0.80%, or 0.95%; Mo 0.12%, 0.20%, 0.25%, or 0.30% Nickel-chromium-molybdenum steels 43xx Ni 1.82%; Cr 0.50–0.80%; Mo 0.25% 43BVxx Ni 1.82%; Cr 0.50%; Mo 0.12%, or 0.35%; V 0.03% min 47xx Ni 1.05%; Cr 0.45%; Mo 0.20%, or 0.35% 81xx Ni 0.30%; Cr 0.40%; Mo 0.12% 81Bxx Ni 0.30%; Cr 0.45%; Mo 0.12%; and added boron[1] 86xx Ni 0.55%; Cr 0.50%; Mo 0.20% 87xx Ni 0.55%; Cr 0.50%; Mo 0.25% 88xx Ni 0.55%; Cr 0.50%; Mo 0.35% 93xx Ni 3.25%; Cr 1.20%; Mo 0.12% 94xx Ni 0.45%; Cr 0.40%; Mo 0.12% 97xx Ni 0.55%; Cr 0.20%; Mo 0.20% 98xx Ni 1.00%; Cr 0.80%; Mo 0.25% Nickel-molybdenum steels 46xx Ni 0.85%, or 1.82%; Mo 0.20%, or 0.25% 48xx Ni 3.50%; Mo 0.25% Chromium steels 50xx Cr 0.27%, 0.40%, 0.50%, or 0.65% 50xxx Cr 0.50%; C 1.00% min 50Bxx Cr 0.28%, or 0.50%; and added boron[1] 51xx Cr 0.80%, 0.87%, 0.92%, 1.00%, or 1.05% 51xxx Cr 1.02%; C 1.00% min. 51Bxx Cr 0.80%; and added boron[1] 52xxx Cr 1.45%; C 1.00% min. Chromium-vanadium steels 61xx Cr 0.60%, 0.80%, 0.95%; V 0.10%, or 0.15% min. Tungsten-chromium steels 72xx W 1.75%; Cr 0.75% Silicon-manganese steels 92xx Si 1.40%, or 2.00%; Mn 0.65%, 0.82%, or 0.85%; Cr 0.00%, or 0.65% High-strength low-alloy steels 9xx Various SAE grades xxBxx Boron steels xxLxx Leaded steels

Stainless steel

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100 Series

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• Type 102—austenitic general purpose stainless steel

200 Series—austenitic chromium-nickel-manganese alloys

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• Type 201— austenitic that is hardenable

300 Series—austenitic chromium-nickel alloys

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400 Series—ferritic and martensitic chromium alloys

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• Type 405—ferritic for welding applications
• Type 408—heat-resistant; poor corrosion resistance; 11% chromium, 8% nickel.
• Type 409—cheapest type; used for automobile exhausts; ferritic (iron/chromium only).
• Type 410—martensitic (high-strength iron/chromium). Wear-resistant, but less corrosion-resistant.[8]
• Type 416—easy to machine due to additional sulfur
• Type 420—Cutlery Grade martensitic; similar to the Brearley's original rustless steel. Excellent polishability.
• Type 430—decorative, e.g., for automotive trim; ferritic. Good formability, but with reduced temperature and corrosion resistance.
• Type 439—ferritic grade, a higher grade version of 409 used for catalytic converter exhaust sections. Increased chromium for improved high temperature corrosion/oxidation resistance.
• Type 440—a higher grade of cutlery steel, with more carbon, allowing for much better edge retention when properly heat-treated. It can be hardened to approximately Rockwell 58 hardness, making it one of the hardest stainless steels. Due to its toughness and relatively low cost, most display-only and replica swords or knives are made of 440 stainless. Available in four grades:
  • Type 440A—has the least amount of carbon making this the most stain-resistant.
  • Type 440B—slightly more carbon than 440A.
  • Type 440C—has the greatest amount of carbon of the type 440 variants. Strongest and considered more desirable in knifemaking than the Type 440A variant[

    citation needed

    ], except for diving or other salt-water applications. This variant is also more readily available than other variants of type 440.[9]
  • Type 440F—a free-machining variant. Contains the same high carbon content as type 440C.
• Type 446—ferritic designed for elevated temperature service and is capable of tolerating molten copper and brass. [10]

500 Series—heat-resisting chromium alloys

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[11]

600 Series—originally created for proprietary alloys (which are no longer given SAE grade numbers)

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• 601 through 604: Martensitic low-alloy steels.
• 610 through 613: Martensitic secondary hardening steels.
• 614 through 619: Martensitic chromium steels.
• 630 through 635: Semiaustenitic and martensitic precipitation hardening stainless steels.
  • Type 630 is most common PH stainless, better known as 17-4; 17% chromium, 4% nickel.
• 650 through 653: Austenitic steels strengthened by hot/cold work.
• 660 through 665: Austenitic superalloys; all grades except alloy 661 are strengthened by second-phase precipitation.

900 series—austenitic chromium-molybdenum alloys

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• Type 904—similar to 316 but with higher chromium and molybdenum content for more corrosion resistance

Stainless steel designations table

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Stainless steel designations Designation Composition by weight (%) SAE UNS Cr Ni C Mn Si P S N Other Austenitic 201 S20100 16–18 3.5–5.5 0.15 5.5–7.5 0.75 0.06 0.03 0.25 - 202 S20200 17–19 4–6 0.15 7.5–10.0 0.75 0.06 0.03 0.25 - 205 S20500 16.5–18 1–1.75 0.12–0.25 14–15.5 0.75 0.06 0.03 0.32–0.40 - 254[13] S31254 20 18 0.02 max. - - - - 0.20 6 Mo; 0.75 Cu; "Super austenitic"; All values nominal 301 S30100 16–18 6–8 0.15 2 0.75 0.045 0.03 - - 302 S30200 17–19 8–10 0.15 2 0.75 0.045 0.03 0.1 - 302B S30215 17–19 8–10 0.15 2 2.0–3.0 0.045 0.03 - - 303 S30300 17–19 8–10 0.15 2 1 0.2 0.15 min. - Mo 0.60 (optional) 303Se S30323 17–19 8–10 0.15 2 1 0.2 0.06 - 0.15 Se min. 304 S30400 18–20 8–10.50 0.08 2 0.75 0.045 0.03 0.1 - 304L S30403 18–20 8–12 0.03 2 0.75 0.045 0.03 0.1 - 304Cu S30430 17–19 8–10 0.08 2 0.75 0.045 0.03 - 3–4 Cu 304N S30451 18–20 8–10.50 0.08 2 0.75 0.045 0.03 0.10–0.16 - 305 S30500 17–19 10.50–13 0.12 2 0.75 0.045 0.03 - - 308 S30800 19–21 10–12 0.08 2 1 0.045 0.03 - - 309 S30900 22–24 12–15 0.2 2 1 0.045 0.03 - - 309S S30908 22–24 12–15 0.08 2 1 0.045 0.03 - - 310 S31000 24–26 19–22 0.25 2 1.5 0.045 0.03 - - 310S S31008 24–26 19–22 0.08 2 1.5 0.045 0.03 - - 314 S31400 23–26 19–22 0.25 2 1.5–3.0 0.045 0.03 - - 316 S31600 16–18 10–14 0.08 2 0.75 0.045 0.03 0.10 2.0–3.0 Mo 316L S31603 16–18 10–14 0.03 2 0.75 0.045 0.03 0.10 2.0–3.0 Mo 316F S31620 16–18 10–14 0.08 2 1 0.2 0.10 min. - 1.75–2.50 Mo 316N S31651 16–18 10–14 0.08 2 0.75 0.045 0.03 0.10–0.16 2.0–3.0 Mo 317 S31700 18–20 11–15 0.08 2 0.75 0.045 0.03 0.10 max. 3.0–4.0 Mo 317L S31703 18–20 11–15 0.03 2 0.75 0.045 0.03 0.10 max. 3.0–4.0 Mo 321 S32100 17–19 9–12 0.08 2 0.75 0.045 0.03 0.10 max. Ti 5(C+N) min., 0.70 max. 329 S32900 23–28 2.5–5 0.08 2 0.75 0.04 0.03 - 1–2 Mo 330 N08330 17–20 34–37 0.08 2 0.75–1.50 0.04 0.03 - - 347 S34700 17–19 9–13 0.08 2 0.75 0.045 0.030 - Nb + Ta, 10 × C min., 1 max. 348 S34800 17–19 9–13 0.08 2 0.75 0.045 0.030 - Nb + Ta, 10 × C min., 1 max., but 0.10 Ta max.; 0.20 Ca 384 S38400 15–17 17–19 0.08 2 1 0.045 0.03 - - Designation Composition by weight (%) SAE UNS Cr Ni C Mn Si P S N Other Ferritic 405 S40500 11.5–14.5 - 0.08 1 1 0.04 0.03 - 0.1–0.3 Al, 0.60 max. 409 S40900 10.5–11.75 0.05 0.08 1 1 0.045 0.03 - Ti 6 × (C + N) [14] 429 S42900 14–16 0.75 0.12 1 1 0.04 0.03 - - 430 S43000 16–18 0.75 0.12 1 1 0.04 0.03 - - 430F S43020 16–18 - 0.12 1.25 1 0.06 0.15 min. - 0.60 Mo (optional) 430FSe S43023 16–18 - 0.12 1.25 1 0.06 0.06 - 0.15 Se min. 434 S43400 16–18 - 0.12 1 1 0.04 0.03 - 0.75–1.25 Mo 436 S43600 16–18 - 0.12 1 1 0.04 0.03 - 0.75–1.25 Mo; Nb+Ta 5 × C min., 0.70 max. 442 S44200 18–23 - 0.2 1 1 0.04 0.03 - - 446 S44600 23–27 0.25 0.2 1.5 1 0.04 0.03 - - Designation Composition by weight (%) SAE UNS Cr Ni C Mn Si P S N Other Martensitic 403 S40300 11.5–13.0 0.60 0.15 1 0.5 0.04 0.03 - - 410 S41000 11.5–13.5 0.75 0.15 1 1 0.04 0.03 - - 414 S41400 11.5–13.5 1.25–2.50 0.15 1 1 0.04 0.03 - - 416 S41600 12–14 - 0.15 1.25 1 0.06 0.15 min. - 0.060 Mo (optional) 416Se S41623 12–14 - 0.15 1.25 1 0.06 0.06 - 0.15 Se min. 420 S42000 12–14 - 0.15 min. 1 1 0.04 0.03 - - 420F S42020 12–14 - 0.15 min. 1.25 1 0.06 0.15 min. - 0.60 Mo max. (optional) 422 S42200 11.0–12.5 0.50–1.0 0.20–0.25 0.5–1.0 0.5 0.025 0.025 - 0.90–1.25 Mo; 0.20–0.30 V; 0.90–1.25 W 431 S41623 15–17 1.25–2.50 0.2 1 1 0.04 0.03 - - 440A S44002 16–18 - 0.60–0.75 1 1 0.04 0.03 - 0.75 Mo 440B S44003 16–18 - 0.75–0.95 1 1 0.04 0.03 - 0.75 Mo 440C S44004 16–18 - 0.95–1.20 1 1 0.04 0.03 - 0.75 Mo Designation Composition by weight (%) SAE UNS Cr Ni C Mn Si P S N Other Heat resisting 501 S50100 4–6 - 0.10 min. 1 1 0.04 0.03 - 0.40–0.65 Mo 502 S50200 4–6 - 0.1 1 1 0.04 0.03 - 0.40–0.65 Mo Martensitic precipitation hardening 630 S17400 15–17 3–5 0.07 1 1 0.04 0.03 - Cu 3–5, Ta 0.15–0.45 [15]

High-strength low-alloy steel

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See also

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References

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Bibliography

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