Steel A387 Gr 22 · grade
Steel A387 Gr 22 Cl.2 N&T
Properties of the Cl.2 N&T condition, compared with the other A387 Gr 22 tempers.
Default strength class for heavy-wall reactors and boiler drums where higher ASME allowable stress reduces wall thickness.
What is A387 Gr 22 Cl.2 N&T?
A387 Gr 22 Cl.2 N&T is A387 Gr 22 in the Cl.2 N&T grade — default strength class for heavy-wall reactors and boiler drums where higher ASME allowable stress reduces wall thickness. A387 Gr 22 Cl.2 N&T 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). A387 Gr 22 Cl.2 N&T 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). N&T is the default condition FabDigit quotes; Cl.2 N&T is available on request or by drawing note.
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 94% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
A387 Gr 22 Cl.2 N&T properties
Typical room-temperature values for A387 Gr 22 Cl.2 N&T — 9 properties are specific to this condition; the rest are grade-level values shared by every A387 Gr 22 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
A387 Gr 22 Cl.2 N&T 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 Cl.2 N&T 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 Cl.2 N&T 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 72% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
A387 Gr 22 Cl.2 N&T 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 Cl.2 N&T 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 Cl.2 N&T's machinability is fair (50/100, worse than 53% of steel grades); weldability good (55/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A387 Gr 22 tempers and conditions
A387 Gr 22 is also supplied in 4 other conditions. The full side-by-side table is on the A387 Gr 22 overview.
- N&TDefaultStandard as-rolled-plate supply condition for hydroprocessing and boiler plate; Class 2 strength level is the most widely stocked.385 MPa yield · 180 HB
- Q&TOrdered 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 MPa yield · 15 HRC
- Cl.2 N&TDefault strength class for heavy-wall reactors and boiler drums where higher ASME allowable stress reduces wall thickness.385 MPa yield · 180 HB
- Cl.1 N&TChoose the lower-strength Class 1 when maximum toughness, easier forming and lower PWHT hardness are wanted over allowable stress.275 MPa yield · 155 HB
- AnnealedSoftest condition, used for heavy cold forming, deep machining or as an intermediate state before final N&T.260 MPa yield · 145 HB
Working with A387 Gr 22 Cl.2 N&T
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.
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.
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 | — |
A387 Gr 22 Cl.2 N&T — frequently asked
What is A387 Gr 22 Cl.2 N&T used for?
A387 Gr 22 Cl.2 N&T 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 Cl.2 N&T?
A387 Gr 22 Cl.2 N&T 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 Cl.2 N&T 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 Cl.2 N&T 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 Cl.2 N&T?
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 Cl.2 N&T 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 Cl.2 N&T?
A387 Gr 22 Cl.2 N&T 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.
Can FabDigit make parts in A387 Gr 22 Cl.2 N&T?
Yes — A387 Gr 22 Cl.2 N&T is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.