Steel A387 Gr 2 CL1-A
Heat-treated state
ASTM A387 Gr 2 · UNS S50460
CL1-A = class 1
Softest, most formable condition; pick for heavily cold-formed shells or where only Class 1 strength is needed.
Values for the CL1-A condition
Other A387 Gr 2 tempers and conditions
A387 Gr 2 is listed in 4 conditions; see the grade overview at A387 Gr 2.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CL1-AThis page Class 1 | Softest, most formable condition; pick for heavily cold-formed shells or where only Class 1 strength is needed. | 265 | 440 | 28 | 145 HB | — |
Class 1 | Class 1 strength with refined normalized grain structure — better toughness than annealed at the same low strength level. | 290 | 470 | 26 | 155 HB | — |
CL2-NTDefault Class 2 | The standard stocked condition — higher Class 2 strength for thinner, lighter pressure-vessel shells and heads. | 320 | 500 | 24 | 170 HB | — |
Class 2 | Use for heavy plate where accelerated cooling is needed to meet Class 2 properties and low-temperature Charpy through thickness. | 360 | 530 | 23 | 180 HB | — |
What is A387 Gr 2 CL1-A?
A387 Gr 2 CL1-A is A387 Gr 2 heat treated to CL1-A — softest, most formable condition; pick for heavily cold-formed shells or where only Class 1 strength is needed. A387 Gr 2 CL1-A has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi). A387 Gr 2 CL1-A 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). CL2-NT is the default condition FabDigit quotes; CL1-A is available on request or by drawing note.
Advantages
- High service temperature — 510°C (950 °F), better than 92% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Low strength — 265 MPa (38.4 ksi), worse than 92% of steel grades
A387 Gr 2 CL1-A properties
Typical room-temperature values for A387 Gr 2 CL1-A; 17 are specific to this condition. Other listed values are A387 Gr 2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A387 Gr 2 CL1-A 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 2 CL1-A has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A387 Gr 2 CL1-A is rated for continuous service to 510°C (950 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
A387 Gr 2 CL1-A conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of A387 Gr 2 CL1-A takes about 29 MJ of energy and emits 2.3 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability8
A387 Gr 2 CL1-A's machinability is good (60/100, better than 83% of steel grades); weldability good (62/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A387 Gr 2 CL1-A
Is A387 Gr 2 easy to machine?
Machines like annealed 4130 at roughly 60 % of 1212 — use rigid setups, carbide inserts and moderate speeds; expect stringy chips in the annealed class.
Can A387 Gr 2 be welded?
Readily welded with matching B2/E8018-B2 consumables; preheat 150–200 °C, control interpass, and apply PWHT at 675–705 °C to restore toughness and avoid hard HAZ.
Can A387 Gr 2 be formed, bent or molded?
Hot forming of heads and shells at 900–1000 °C followed by re-normalizing/tempering is standard; cold rolling is possible but limit strains and re-heat-treat if severe.
What surface finishes work on A387 Gr 2?
No anodizing; specify shot blast plus epoxy/silicone-aluminium paint, aluminizing or a stainless/Alloy weld overlay for corrosive process sides.
A387 Gr 2 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 |
|---|---|---|
| C0.05–0.21 for plate ≤ 25 mm; upper limit per A387 Gr 2 | 0.05 – 0.21 | 0.13 |
| Mn | 0.55 – 0.8 | 0.68 |
| P | ≤ 0.04 | 0.01 |
| S | ≤ 0.04 | 0.01 |
| Si | 0.15 – 0.4 | 0.25 |
| Cr | 0.5 – 0.8 | 0.65 |
| Mo | 0.45 – 0.6 | 0.52 |
| Fe | balance | — |
A387 Gr 2 CL1-A — frequently asked
What is A387 Gr 2 CL1-A used for?
A387 Gr 2 CL1-A is typically used for boiler and pressure vessel plate, steam drums and process vessel shells. In short: entry-level chrome-moly plate; economical to 510 °C; readily welded vessel steel.
What is the yield strength of A387 Gr 2 CL1-A?
A387 Gr 2 CL1-A has a typical yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A387 Gr 2 CL1-A easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like annealed 4130 at roughly 60 % of 1212 — use rigid setups, carbide inserts and moderate speeds; expect stringy chips in the annealed class.
Can A387 Gr 2 CL1-A be welded?
Yes — weldability is rated good (62/100). Readily welded with matching B2/E8018-B2 consumables; preheat 150–200 °C, control interpass, and apply PWHT at 675–705 °C to restore toughness and avoid hard HAZ.
What surface finishes work on A387 Gr 2 CL1-A?
No anodizing; specify shot blast plus epoxy/silicone-aluminium paint, aluminizing or a stainless/Alloy weld overlay for corrosive process sides.
Can A387 Gr 2 CL1-A be formed, bent or molded?
Hot forming of heads and shells at 900–1000 °C followed by re-normalizing/tempering is standard; cold rolling is possible but limit strains and re-heat-treat if severe.
What is the maximum service temperature of A387 Gr 2 CL1-A?
A387 Gr 2 CL1-A is rated for continuous use to about 510°C (950 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A387 Gr 2 CL2-NT and A387 Gr 2 CL1-A?
CL2-NT is the default condition — the standard stocked condition — higher Class 2 strength for thinner, lighter pressure-vessel shells and heads. CL1-A: softest, most formable condition; pick for heavily cold-formed shells or where only Class 1 strength is needed. Yield strength is 320 MPa in CL2-NT versus 265 MPa in CL1-A.
Sources
- ASTM A387/A387M — Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum — ASTM International (2021)
- 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. 6 — Welding, Brazing, and Soldering (Cr-Mo steels) — ASM International (1993)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
- GB/T 713 (15CrMo comparable grade) — SAC (2014)
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.