Steel 15CrMo
GB 15CrMo · ASTM A335 Grade P11
15CrMo is a 1.25Cr-0.5Mo heat-resistant low-alloy steel, equivalent to A335 Grade P11, A387 Gr 12, 13CrMo4-5 (1.7335) and STPA23.
Values for the HR condition
15CrMo tempers and conditions
15CrMo is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/soft anneal, ≤179 HB | Pick for maximum machinability and cold formability, or to soften after forging before final normalize-and-temper. | 265 | 460 | 26 | 145 HB | — |
Normalized and tempered | Standard GB/T 3077 and GB 5310 supply condition for boiler tubes, headers and pressure plate — best balance of creep strength, toughness and weld compatibility. | 300 | 490 | 25 | 150 HB | — |
HRDefault Hot rolled | Most commonly stocked mill condition for 15CrMo plate, bar and seamless tube before final heat treatment or as-supplied for general pressure work. | 305 | 500 | 22 | 155 HB | — |
~900–930 °C air cool | Use to refine grain and homogenise forgings/plate; higher strength than annealed but usually followed by a temper for pressure service. | 340 | 525 | 22 | 165 HB | — |
Cold rolled | Thin strip/sheet condition for stamped heat-resistant parts and small tubing stock; usually annealed after forming. | 430 | 570 | 14 | 10 HRC | 7.7 % IACS |
Cold drawn | Pick for small-diameter bar needing tight tolerance, bright finish and higher yield strength without heat treatment. | 500 | 620 | 12 | 185 HB | — |
Quenched and tempered | Choose for high-temperature bolting, valve stems and shafts where higher yield strength and toughness than N&T are needed below ~500 °C. | 550 | 700 | 18 | 19 HRC | — |
What is 15CrMo?
15CrMo is a 1.25Cr-0.5Mo heat-resistant low-alloy steel, equivalent to A335 Grade P11, A387 Gr 12, 13CrMo4-5 (1.7335) and STPA23. Engineers use it for boiler tubes, superheaters and hot petrochemical piping at service temperatures up to about 550 °C, where creep strength and hydrogen resistance exceed carbon steel at moderate cost; usual forms are seamless tube, plate, bar and forgings, with about 305 MPa yield, 500 MPa tensile and 22% elongation at 155 HB. It has no ambient corrosion resistance, needs 150–250 °C preheat and 680–720 °C PWHT, and above roughly 580 °C P91 or P92 give much higher allowable stress. 15CrMo 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). 15CrMo has a yield strength of 305 MPa (44.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 84% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
What is 15CrMo used for?
- Boiler superheater tubes
- Hot petrochemical piping
- Steam headers and manifolds
- Pressure vessel plate for hydrogen service
- Forged flanges and pipe fittings
- Elevated-temperature pressure parts
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- Low strength — 305 MPa (44.2 ksi), worse than 84% of steel grades
15CrMo properties
Typical room-temperature values for 15CrMo-HR; bars are the position among steel grades.
Physical3
15CrMo 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
15CrMo has a yield strength of 305 MPa (44.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 84% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
15CrMo is rated for continuous service to 550°C (1,022 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.1 µm/m·K (6.72 µin/in·°F).
Electrical3
15CrMo conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of 15CrMo takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability8
15CrMo's machinability is fair (54/100, better than 54% of steel grades); weldability good (60/100); formability good (55/100).
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. 15CrMo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 15CrMo
Is 15CrMo easy to machine?
Machines like normalized 4130 at ~60 % of 1212; carbide tooling, rigid setups and moderate speeds — anneal or N&T before heavy cuts and expect work hardening in the Q&T condition.
Can 15CrMo be welded?
Weldable with matched E8018-B2 / ER80S-B2 consumables, preheat 150–250 °C, interpass ≤300 °C and PWHT 680–720 °C to soften the martensitic HAZ and restore creep ductility.
Can 15CrMo be formed, bent or molded?
Hot forms readily at 1100–850 °C; cold bending of tube is possible with generous radii, but re-normalize and temper after severe cold work.
Manufacturability
The process limits FabDigit applies to 15CrMo. Every 15CrMo part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair54 / 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 | Fair55 / 100 |
|---|---|
| Weldability | Better60 / 100 |
15CrMo 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 |
|---|---|---|
| C | 0.12 – 0.18 | 0.15 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.4 – 0.7 | 0.55 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.4 – 0.55 | 0.48 |
| Niresidual | ≤ 0.3 | |
| Curesidual | ≤ 0.2 | |
| Pimpurity | ≤ 0.03 | |
| Simpurity | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 15CrMo?
No anodizing; protect with phosphate + high-temperature aluminium paint, aluminizing or thermal insulation, since the alloy rusts freely below the dew point.
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 15CrMo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A335 Grade P11
- Similar grades
- A387 Gr1213CrMo4-51.7335STPA23
How much does 15CrMo cost?
15CrMo 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.
15CrMo — frequently asked
What is 15CrMo used for?
15CrMo is typically used for boiler superheater tubes, hot petrochemical piping, steam headers and manifolds, pressure vessel plate for hydrogen service, forged flanges and pipe fittings and elevated-temperature pressure parts. In short: chrome-moly boiler pipe.
What is the yield strength of 15CrMo?
15CrMo has a typical yield strength of 305 MPa (44.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 84% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 15CrMo easy to machine?
Reasonably — machinability is rated fair (54/100, better than 54% of steel grades). Machines like normalized 4130 at ~60 % of 1212; carbide tooling, rigid setups and moderate speeds — anneal or N&T before heavy cuts and expect work hardening in the Q&T condition.
Can 15CrMo be welded?
Yes — weldability is rated good (60/100). Weldable with matched E8018-B2 / ER80S-B2 consumables, preheat 150–250 °C, interpass ≤300 °C and PWHT 680–720 °C to soften the martensitic HAZ and restore creep ductility.
What surface finishes work on 15CrMo?
No anodizing; protect with phosphate + high-temperature aluminium paint, aluminizing or thermal insulation, since the alloy rusts freely below the dew point.
Can 15CrMo be formed, bent or molded?
Hot forms readily at 1100–850 °C; cold bending of tube is possible with generous radii, but re-normalize and temper after severe cold work.
What is the maximum service temperature of 15CrMo?
15CrMo 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.
What is the difference between 15CrMo-HR and 15CrMo-CD?
HR is the default condition — most commonly stocked mill condition for 15CrMo plate, bar and seamless tube before final heat treatment or as-supplied for general pressure work. CD: pick for small-diameter bar needing tight tolerance, bright finish and higher yield strength without heat treatment. Yield strength is 305 MPa in HR versus 500 MPa in CD.
How much does 15CrMo cost?
15CrMo 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 15CrMo?
Yes — 15CrMo 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
- GB/T 3077 Alloy structural steels (2015)
- GB 5310 Seamless steel tubes for high pressure boilers — SAC (2017)
- ASTM A335/A335M Grade P12 seamless ferritic alloy-steel pipe — ASTM International (2023)
- EN 10216-2 (13CrMo4-5, 1.7335) seamless steel tubes for pressure purposes — CEN (2020)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASME BPVC Section II Part D — physical properties and allowable stresses — ASME (2023)
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.