Steel A225
ASTM A225
A225 is a manganese-vanadium-nickel alloy pressure-vessel plate (Grades C and D) supplied normalized, normalized plus stress relieved, or quenched and tempered.
Reference datasheet — A225 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 GrC-N condition
A225 tempers and conditions
A225 is supplied in 5 conditions, soft to hard. GrC-N is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
GrC-NDefault Grade C, Normalized | Higher-strength A225 level; standard supply condition for thick high-pressure vessel shells where wall thickness must be minimized. | 345 | 540 | 24 | 160 HB | 44 W/m·K |
Grade D, Normalized + Stress Relieved | Grade D plate delivered in the PWHT-simulated condition for heavy welded drums requiring guaranteed post-heat-treatment properties. | 365 | 560 | 25 | 163 HB | 7.5 % IACS |
Grade D, Normalized | Lower-carbon/lower-strength A225 level; chosen when better toughness, bendability and weld reliability matter more than peak strength. | 430 | 620 | 20 | 190 HB | 42 W/m·K |
Grade C, Normalized + Stress Relieved | Use when plate must be qualified after simulated post-weld heat treatment of heavy welded shells; slight strength loss, improved dimensional stability. | 440 | 660 | 22 | 192 HB | 8 % IACS |
Grade C, Quenched and Tempered | Optional accelerated-cooled/tempered condition for very heavy plate needing through-thickness strength and low-temperature toughness. | 520 | 720 | 20 | 19 HRC | 8 % IACS |
What is A225?
A225 is a manganese-vanadium-nickel alloy pressure-vessel plate (Grades C and D) supplied normalized, normalized plus stress relieved, or quenched and tempered. It was used historically for high-pressure hydrogen reactor vessels where high strength was needed in heavy section. Normalized Grade C gives about 345 MPa yield, 540 MPa tensile, 24 % elongation, 160 HB, 205 GPa modulus, 44 W/m·K and density 7.85 g/cm³, with service to 425 °C. Weldability is only moderate (score 70, CE about 0.5–0.6) and the vanadium-bearing HAZ is crack-sensitive; availability is limited, and Mn-Mo or 2.25Cr-1Mo pressure vessel plate is the usual current substitute. A225 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). A225 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 75% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
What is A225 used for?
- High-pressure reactor vessels
- Hydrogenation and hydroprocessing equipment shells
- Heavy-wall pressure vessel plate
- Formed reactor heads
- Ammonia and synthesis converter shells
- Thick-section vessel shell courses
Limitations
- Low strength — 345 MPa (50 ksi), worse than 75% of steel grades
A225 properties
Typical room-temperature values for A225-GrC-N; bars are the position among steel grades.
Physical3
A225 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
A225 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 75% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A225 is rated for continuous service to 425°C (797 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A225 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of A225 takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
A225's machinability is good (58/100, better than 75% of steel grades); weldability very good (70/100); formability good (60/100).
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. A225 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A225
Is A225 easy to machine?
Machines like normalized 1.3–1.5 %Mn low-alloy plate (~55 % of AISI 1212); use rigid setups, carbide inserts, moderate speeds, and expect abrasive V-carbide wear in the Grade C condition.
Can A225 be welded?
Weldable with low-hydrogen SMAW/SAW but CE ≈ 0.5–0.6: preheat 100–150 °C, control interpass, use low-hydrogen consumables and apply PWHT at 590–620 °C — V-bearing HAZ is prone to reheat/hardening cracking.
Can A225 be formed, bent or molded?
Heavy plate is hot-formed or warm-formed for heads and shells; cold rolling of thin gauges is possible at generous bend radii (≥3t) with renormalizing if strain is large.
A225 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 |
|---|---|---|
| CGrade C up to ~0.25; Grade D held lower (~0.20 max) for toughness/weldability | ≤ 0.25 | 0.2 |
| Mnprincipal strengthener | 1.1 – 1.6 | 1.35 |
| Sikilled steel | 0.13 – 0.45 | 0.28 |
| Nitoughness / hardenability | 0.4 – 0.7 | 0.55 |
| Vprecipitation strengthening; drives PWHT sensitivity | 0.1 – 0.18 | 0.14 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Fe | balance |
What surface finishes work on A225?
No inherent corrosion resistance — shot blast then prime/paint, weld-overlay or clad with stainless/Alloy 625 for process-side service; add a corrosion allowance in wall-thickness design.
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 A225 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A225 Grade C
How much does A225 cost?
A225 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.
A225 — frequently asked
What is A225 used for?
A225 is typically used for high-pressure reactor vessels, hydrogenation and hydroprocessing equipment shells, heavy-wall pressure vessel plate, formed reactor heads, ammonia and synthesis converter shells and thick-section vessel shell courses. In short: high-strength heavy-wall vessel plate; crack-sensitive V-bearing HAZ; legacy hydrogen reactor grade.
What is the yield strength of A225?
A225 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 75% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A225 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like normalized 1.3–1.5 %Mn low-alloy plate (~55 % of AISI 1212); use rigid setups, carbide inserts, moderate speeds, and expect abrasive V-carbide wear in the Grade C condition.
Can A225 be welded?
Yes — weldability is rated very good (70/100). Weldable with low-hydrogen SMAW/SAW but CE ≈ 0.5–0.6: preheat 100–150 °C, control interpass, use low-hydrogen consumables and apply PWHT at 590–620 °C — V-bearing HAZ is prone to reheat/hardening cracking.
What surface finishes work on A225?
No inherent corrosion resistance — shot blast then prime/paint, weld-overlay or clad with stainless/Alloy 625 for process-side service; add a corrosion allowance in wall-thickness design.
Can A225 be formed, bent or molded?
Heavy plate is hot-formed or warm-formed for heads and shells; cold rolling of thin gauges is possible at generous bend radii (≥3t) with renormalizing if strain is large.
What is the maximum service temperature of A225?
A225 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 A225 GrC-N and A225 GrC-QT?
GrC-N is the default condition — higher-strength A225 level; standard supply condition for thick high-pressure vessel shells where wall thickness must be minimized. GrC-QT: optional accelerated-cooled/tempered condition for very heavy plate needing through-thickness strength and low-temperature toughness. Yield strength is 345 MPa in GrC-N versus 520 MPa in GrC-QT.
How much does A225 cost?
A225 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 A225/A225M Standard Specification for Pressure Vessel Plates, Alloy Steel, Manganese-Vanadium-Nickel (withdrawn) — ASTM International (2003)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 19 — Fatigue and Fracture — ASM International (1996)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures and Pressures — API (2016)
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.