Steel A225 GrC-QT
Heat-treated state
ASTM A225
GrC-QT = grade C, Quenched and Tempered
Optional accelerated-cooled/tempered condition for very heavy plate needing through-thickness strength and low-temperature toughness.
Values for the GrC-QT condition
Other A225 tempers and conditions
A225 is listed in 5 conditions; see the grade overview at A225.
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 |
GrC-QTThis page 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 GrC-QT?
A225 GrC-QT is A225 heat treated to GrC-QT — optional accelerated-cooled/tempered condition for very heavy plate needing through-thickness strength and low-temperature toughness. A225 GrC-QT has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 67% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). A225 GrC-QT 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). GrC-N is the default condition FabDigit quotes; GrC-QT is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 150 MPa·√m (136.5 ksi·√in), better than 96% of steel grades
A225 GrC-QT properties
Typical room-temperature values for A225 GrC-QT; 23 are specific to this condition. Other listed values are A225 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A225 GrC-QT 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 GrC-QT has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 67% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A225 GrC-QT is rated for continuous service to 400°C (752 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A225 GrC-QT conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A225 GrC-QT 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 GrC-QT's machinability is fair (46/100, worse than 59% of steel grades); weldability fair (50/100); formability fair (38/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A225 GrC-QT
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.
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.
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 | — |
A225 GrC-QT — frequently asked
What is A225 GrC-QT used for?
A225 GrC-QT 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 GrC-QT?
A225 GrC-QT has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A225 GrC-QT easy to machine?
Reasonably — machinability is rated fair (46/100, worse than 59% 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 GrC-QT be welded?
With care — weldability is rated fair (50/100). 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 GrC-QT?
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 GrC-QT 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 GrC-QT?
A225 GrC-QT is rated for continuous use to about 400°C (752 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.