Steel A204 Annealed
Temper
ASTM A204 · UNS K12822
Pick when maximum ductility, lowest residual stress and easiest machining/forming are needed.
Values for the Annealed condition
Other A204 tempers and conditions
A204 is listed in 8 conditions; see the grade overview at A204.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page full anneal / stress-relief annealed plate | Pick when maximum ductility, lowest residual stress and easiest machining/forming are needed. | 290 | 475 | 27 | 145 HB | 8.3 % IACS |
Grade A | Choose Grade A when maximum weldability and ductility matter more than allowable stress. | 290 | 500 | 27 | 140 HB | 44 W/m·K |
HRDefault Hot rolled | Standard stocked condition for thinner A204 plate where as-rolled properties meet the grade minima. | 315 | 520 | 24 | 160 HB | 8.2 % IACS |
Grade B | Most widely stocked A204 grade; default choice for boiler drums and elevated-temperature vessels. | 315 | 540 | 25 | 152 HB | 43 W/m·K |
austenitized and air cooled | Standard condition for heavier plate (and mandatory above certain thicknesses) to refine grain and even out properties. | 325 | 515 | 25 | 155 HB | 8.2 % IACS |
Normalized and tempered | Best balance of strength and notch toughness for code vessels with low-temperature impact requirements. | 330 | 505 | 26 | 155 HB | 8.2 % IACS |
Grade C | Use where the thinnest possible shell is wanted; slightly higher carbon so welding controls are stricter. | 340 | 575 | 23 | 163 HB | 43 W/m·K |
Quenched and tempered | Used for thick sections or when the upper end of the tensile range plus high toughness is required. | 405 | 570 | 22 | 180 HB | 8 % IACS |
What is A204 Annealed?
A204 Annealed is A204 in the Annealed temper — pick when maximum ductility, lowest residual stress and easiest machining/forming are needed. A204 Annealed has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 88% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi). A204 Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). HR is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 62/100, better than 89% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- Forms and bends easily — 68/100, better than 83% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Low strength — 290 MPa (42.1 ksi), worse than 88% of steel grades
A204 Annealed properties
Typical room-temperature values for A204 Annealed; 22 are specific to this condition. Other listed values are A204 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A204 Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
A204 Annealed has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 88% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A204 Annealed is rated for continuous service to 480°C (896 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
A204 Annealed conducts electricity at 8.3 % IACS, better than 62% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A204 Annealed takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability8
A204 Annealed's machinability is good (62/100, better than 89% of steel grades); weldability very good (72/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A204 Annealed
Is A204 easy to machine?
Machines like a 190 HB low-alloy steel — carbide tooling, moderate speeds, good chip control; slightly gummier than plain carbon steel due to Mo.
Can A204 be welded?
Readily welded with matching 0.5Mo consumables (E7018-A1 / ER80S-D2); preheat ~100–150 °C on thick plate and apply PWHT at 620–680 °C per code.
Can A204 be formed, bent or molded?
Cold-form only mild radii; hot form heads at 900–1000 °C and re-normalize afterwards to restore properties.
What surface finishes work on A204?
Blast and paint, phosphate or metallize; no anodizing — for corrosive service use stainless weld overlay or roll-bonded clad plate.
A204 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 |
|---|---|---|
| CGr.A ≤0.25, Gr.B ≤0.27, Gr.C ≤0.28 (thickness dependent) | ≤ 0.27 | 0.2 |
| Mnheat analysis max; Gr.C to 0.90 | ≤ 0.9 | 0.7 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Si | 0.15 – 0.4 | 0.25 |
| Mocreep-strengthening addition | 0.45 – 0.6 | 0.5 |
| Fe | balance | — |
A204 Annealed — frequently asked
What is A204 Annealed used for?
A204 Annealed is typically used for boilers, storage tanks and refinery vessels. In short: molybdenum pressure plate.
What is the yield strength of A204 Annealed?
A204 Annealed has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 88% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is A204 Annealed easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines like a 190 HB low-alloy steel — carbide tooling, moderate speeds, good chip control; slightly gummier than plain carbon steel due to Mo.
Can A204 Annealed be welded?
Yes — weldability is rated very good (72/100). Readily welded with matching 0.5Mo consumables (E7018-A1 / ER80S-D2); preheat ~100–150 °C on thick plate and apply PWHT at 620–680 °C per code.
What surface finishes work on A204 Annealed?
Blast and paint, phosphate or metallize; no anodizing — for corrosive service use stainless weld overlay or roll-bonded clad plate.
Can A204 Annealed be formed, bent or molded?
Cold-form only mild radii; hot form heads at 900–1000 °C and re-normalize afterwards to restore properties.
What is the maximum service temperature of A204 Annealed?
A204 Annealed is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in A204 Annealed?
Yes — A204 Annealed is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A204/A204M — Pressure Vessel Plates, Alloy Steel, Molybdenum — ASTM International (2019)
- ASME BPVC Section II Part A (SA-204) and Part D (allowable stresses, physical properties) — ASME (2023)
- EN 10028-2 (16Mo3) — Flat products for pressure purposes, creep-resisting steels — CEN (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13C / Vol.19 — Corrosion and Fatigue of steels — ASM International (2006)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.