Steel A299
ASTM A299
A299 Grade A/B is a manganese-silicon alloy pressure-vessel plate that offers higher strength than plain carbon plates such as A285 or A515.
Reference datasheet — A299 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the GrA-AR condition
A299 tempers and conditions
A299 is supplied in 7 conditions, soft to hard. GrA-AR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized + stress relieved / simulated PWHT | Ordered when plate must be tested in the simulated post-weld-heat-treated condition for code vessels. | 315 | 555 | 25 | 155 HB | 10 % IACS |
GrA-ARDefault Grade A, as-rolled | Default stock condition for A299 Grade A plate up to about 38 mm where no normalizing is specified. | 320 | 560 | 23 | 160 HB | 10 % IACS |
ASTM A299 Grade A | Lower-strength grade of ASTM A299 carbon-manganese-silicon plate for welded boilers and pressure vessels, supplied as-rolled or normalized per thickness. | 320 | 560 | 24 | 160 HB | 49 W/m·K |
Grade A, normalized | Choose for thick plate (>38 mm) or where finer grain and better notch toughness are required. | 330 | 545 | 25 | 155 HB | — |
ASTM A299 Grade B | Higher-strength grade of ASTM A299 Mn-Si plate, same chemistry family as Grade A but tested to a raised tensile/yield band for thicker vessel shells. | 350 | 600 | 22 | 175 HB | 48 W/m·K |
Grade B, as-rolled | Higher-strength grade of A299 for maximum allowable stress / minimum wall thickness in as-rolled plate. | 360 | 600 | 21 | 175 HB | — |
Grade B, normalized | Grade B in heavy sections or where toughness and through-thickness uniformity matter. | 370 | 585 | 23 | 170 HB | 10 % IACS |
What is A299?
A299 Grade A/B is a manganese-silicon alloy pressure-vessel plate that offers higher strength than plain carbon plates such as A285 or A515. It is supplied as-rolled, normalized, or normalized and stress relieved for code vessels, boiler shells and hot-formed heads; the default condition gives 320 MPa yield, 560 MPa tensile, 23 % elongation and about 160 HB, with service to 425 °C. It welds with low-hydrogen consumables, but the carbon equivalent near 0.45 calls for preheat on thick plate plus PWHT, and the plate has no inherent corrosion resistance. Mn-Mo A302 is the next step up for thick-section vessels. A299 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). A299 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 81% of steel grades. Elongation at break is 23% and the elastic modulus is 200 GPa (29 Msi).
What is A299 used for?
- Pressure vessels
- Boiler shells
- Storage tanks
Advantages
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
A299 properties
Typical room-temperature values for A299-GrA-AR; bars are the position among steel grades.
Physical3
A299 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A299 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 81% of steel grades. Elongation at break is 23% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A299 is rated for continuous service to 425°C (797 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A299 conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A299 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
A299's machinability is good (55/100, better than 62% of steel grades); weldability very good (72/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A299 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A299
Is A299 easy to machine?
Machines like medium-carbon C-Mn plate (~60 % of AISI 1212); use rigid setups, carbide tooling and moderate speeds — as-rolled banded structure can give stringy chips.
Can A299 be welded?
Weldable by SMAW/SAW/GMAW with low-hydrogen consumables; carbon equivalent near 0.45 means preheat 100–150 °C on thick plate and PWHT at 595–650 °C for code vessels.
Can A299 be formed, bent or molded?
Hot-form heads and shells at 900–1000 °C followed by re-normalizing; cold rolling of shells is practical with generous bend radii due to the higher yield strength.
A299 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C0.28 max ≤25 mm; increases with thickness (to ~0.30–0.33) | ≤ 0.3 | 0.26 |
| Mn0.90–1.40 for ≤25 mm; 1.15–1.50 for thicker plate | 0.9 – 1.5 | 1.25 |
| Si | 0.15 – 0.4 | 0.25 |
| Pheat analysis max | ≤ 0.04 | 0.02 |
| Sheat analysis max | ≤ 0.04 | 0.01 |
| Febalance, residual Cu/Ni/Cr/Mo per A20 limits | balance |
What surface finishes work on A299?
No inherent corrosion resistance — shot blast to SA 2.5 and apply epoxy/zinc-rich primer, galvanizing or internal cladding; polishing gives only utility finishes.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A299 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A299 Grade A/B
How much does A299 cost?
A299 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A299 — frequently asked
What is A299 used for?
A299 is typically used for pressure vessels, boiler shells and storage tanks. In short: stronger than A285/A515; weldable C-Mn vessel plate; 425 °C service limit.
What is the yield strength of A299?
A299 has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is A299 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like medium-carbon C-Mn plate (~60 % of AISI 1212); use rigid setups, carbide tooling and moderate speeds — as-rolled banded structure can give stringy chips.
Can A299 be welded?
Yes — weldability is rated very good (72/100). Weldable by SMAW/SAW/GMAW with low-hydrogen consumables; carbon equivalent near 0.45 means preheat 100–150 °C on thick plate and PWHT at 595–650 °C for code vessels.
What surface finishes work on A299?
No inherent corrosion resistance — shot blast to SA 2.5 and apply epoxy/zinc-rich primer, galvanizing or internal cladding; polishing gives only utility finishes.
Can A299 be formed, bent or molded?
Hot-form heads and shells at 900–1000 °C followed by re-normalizing; cold rolling of shells is practical with generous bend radii due to the higher yield strength.
What is the maximum service temperature of A299?
A299 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A299 GrA-AR and A299 GrB-N?
GrA-AR is the default condition — default stock condition for A299 Grade A plate up to about 38 mm where no normalizing is specified. GrB-N: grade B in heavy sections or where toughness and through-thickness uniformity matter. Yield strength is 320 MPa in GrA-AR versus 370 MPa in GrB-N.
How much does A299 cost?
A299 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A299/A299M — Pressure Vessel Plates, Carbon Steel, Manganese-Silicon — ASTM International (2020)
- ASTM A20/A20M — General Requirements for Steel Plates for Pressure Vessels — ASTM International (2020)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.