Steel A387 Gr 22
ASTM A387 Gr 22 · UNS K21590
A387 Grade 22 (K21590, 10CrMo9-10, 1.7380, SCMV5, 12Cr2Mo1) is a 2.25Cr-1Mo low-alloy pressure vessel plate supplied normalized and tempered in Class 1 or Class 2 strength levels.
Values for the N&T condition
A387 Gr 22 tempers and conditions
A387 Gr 22 is supplied in 5 conditions, soft to hard. N&T 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 |
|---|---|---|---|---|---|---|
full anneal / isothermal anneal | Softest condition, used for heavy cold forming, deep machining or as an intermediate state before final N&T. | 260 | 470 | 28 | 145 HB | 7.8 % IACS |
Class 1, Normalized & Tempered | Choose the lower-strength Class 1 when maximum toughness, easier forming and lower PWHT hardness are wanted over allowable stress. | 275 | 490 | 27 | 155 HB | — |
N&TDefault Normalized and tempered | Standard as-rolled-plate supply condition for hydroprocessing and boiler plate; Class 2 strength level is the most widely stocked. | 385 | 570 | 24 | 180 HB | — |
Class 2, Normalized & Tempered | Default strength class for heavy-wall reactors and boiler drums where higher ASME allowable stress reduces wall thickness. | 385 | 570 | 24 | 180 HB | 7.5 % IACS |
Quenched and tempered | Ordered when uniform through-thickness properties and higher low-temperature toughness are needed in very heavy plate; permitted as an alternative heat treatment with agreement. | 460 | 620 | 22 | 15 HRC | — |
What is A387 Gr 22?
A387 Grade 22 (K21590, 10CrMo9-10, 1.7380, SCMV5, 12Cr2Mo1) is a 2.25Cr-1Mo low-alloy pressure vessel plate supplied normalized and tempered in Class 1 or Class 2 strength levels. It is the most widely used Cr-Mo plate for refinery and power industry equipment, offering good creep and high-temperature hydrogen-attack resistance to about 600 °C; default N&T values are 385 MPa yield, 570 MPa tensile, 24 % elongation and 180 HB with 550 °C listed as maximum service temperature. It is not corrosion resistant, needs mandatory PWHT and control of step-cooling embrittlement; A387 Gr 11 covers milder duty. A387 Gr 22 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). A387 Gr 22 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
What is A387 Gr 22 used for?
- Hydroprocessing reactor shells
- Hydrocracker vessels
- Refinery heat exchanger shells and tubesheets
- Hot petrochemical reactors
- Steam headers and piping components
- Coke drum shells
- Heavy vessel heads and nozzles
Advantages
- Tough — resists crack growth — 180 MPa·√m (163.8 ksi·√in), better than 99% of steel grades
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
A387 Gr 22 properties
Typical room-temperature values for A387 Gr 22-N&T; bars are the position among steel grades.
Physical3
A387 Gr 22 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
A387 Gr 22 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A387 Gr 22 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
A387 Gr 22 has an electrical resistivity of 2.3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A387 Gr 22 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
A387 Gr 22's machinability is fair (50/100, worse than 53% of steel grades); weldability good (55/100); formability fair (50/100).
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. A387 Gr 22 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A387 Gr 22
Is A387 Gr 22 easy to machine?
Machines like a 180 HB low-alloy steel — rigid setups, carbide tooling, moderate speeds; expect abrasive Cr-Mo carbides and plan stress-relief between heavy cuts.
Can A387 Gr 22 be welded?
Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass control and mandatory PWHT 690–730 °C; control step-cooling embrittlement (J-factor, X-bar) for hydrogen service.
Can A387 Gr 22 be formed, bent or molded?
Hot form at 900–1000 °C then re-normalize and temper; cold forming is possible on thin plate but requires re-heat-treatment to restore properties.
Manufacturability
The process limits FabDigit applies to A387 Gr 22. Every A387 Gr 22 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair50 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair50 / 100 |
|---|---|
| Weldability | Better55 / 100 |
| Bendable | Yes |
A387 Gr 22 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 |
|---|---|---|
| C0.05–0.15 for both classes | 0.05 – 0.15 | 0.12 |
| Mn | 0.3 – 0.6 | 0.45 |
| Si0.50 max | ≤ 0.5 | 0.25 |
| P0.035 max in older editions; low-P for hydrogen service | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Cr1.88–2.62 in some product analyses | 2 – 2.5 | 2.25 |
| Mo | 0.9 – 1.1 | 1 |
| Fe | balance |
What surface finishes work on A387 Gr 22?
Not corrosion resistant — shot blast plus epoxy paint for external surfaces, or 309/347 stainless weld overlay / roll-bonded cladding on process-side surfaces.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A387 Gr 22 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- K21590
- ASTM
- A387 Grade 22
- Similar grades
- 10CrMo9-101.7380SCMV512Cr2Mo1
How much does A387 Gr 22 cost?
A387 Gr 22 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A387 Gr 22 — frequently asked
What is A387 Gr 22 used for?
A387 Gr 22 is typically used for hydroprocessing reactor shells, hydrocracker vessels, refinery heat exchanger shells and tubesheets, hot petrochemical reactors, steam headers and piping components and coke drum shells. In short: chrome-moly pressure plate.
What is the yield strength of A387 Gr 22?
A387 Gr 22 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A387 Gr 22 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like a 180 HB low-alloy steel — rigid setups, carbide tooling, moderate speeds; expect abrasive Cr-Mo carbides and plan stress-relief between heavy cuts.
Can A387 Gr 22 be welded?
Yes — weldability is rated good (55/100). Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass control and mandatory PWHT 690–730 °C; control step-cooling embrittlement (J-factor, X-bar) for hydrogen service.
What surface finishes work on A387 Gr 22?
Not corrosion resistant — shot blast plus epoxy paint for external surfaces, or 309/347 stainless weld overlay / roll-bonded cladding on process-side surfaces.
Can A387 Gr 22 be formed, bent or molded?
Hot form at 900–1000 °C then re-normalize and temper; cold forming is possible on thin plate but requires re-heat-treatment to restore properties.
What is the maximum service temperature of A387 Gr 22?
A387 Gr 22 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does A387 Gr 22 cost?
A387 Gr 22 is a standard-cost steel ($$), cheaper than about 71% 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.
Can FabDigit make parts in A387 Gr 22?
Yes — A387 Gr 22 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 A387/A387M — Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum — ASTM International (2021)
- ASME BPVC Section II Part A (SA-387) and Part D (allowable stresses, physical properties) — ASME (2023)
- GB/T 713 (12Cr2Mo1R ) — SAC (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- API 934-A / API 941 — heavy-wall Cr-Mo reactor and Nelson curve practice — API (2019)
- Mysteel / SMM (2025)
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.