Steel C300-CR (Cold rolled)
Supply condition
EN 18Ni Maraging 300 · AMS 6514
Thin sheet and strip with smooth surface and light cold work; formed to shape then aged (weld first, age last).
Values for the CR condition
Other C300 tempers and conditions
C300 is listed in 8 conditions; see the grade overview at C300.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
900–980 °C grain-refining anneal + air cool (intermediate homogenising treatment) | Intermediate treatment used to refine coarse as-cast/as-forged grain before the 815 °C solution anneal; not a final delivery condition. | 790 | 1,000 | 16 | 31 HRC | 2.9 % IACS |
solution annealed 815 °C / 1 h, air cool (as-supplied soft martensite) | Standard as-shipped condition (~30 HRC): machine, form and weld here, then age to final strength. | 800 | 1,010 | 17 | 30 HRC | — |
HRDefault Hot rolled | Mill hot-worked stock with scale and looser tolerances; solution anneal and age before use. | 850 | 1,050 | 13 | 32 HRC | 2.9 % IACS |
Cold drawn | Bright, close-tolerance bar or wire with modest cold-work strengthening; still machinable and can be aged afterwards. | 1,000 | 1,150 | 10 | 34 HRC | 2.9 % IACS |
CRThis page Cold rolled | Thin sheet and strip with smooth surface and light cold work; formed to shape then aged (weld first, age last). | 1,050 | 1,180 | 7 | 35 HRC | 2.9 % IACS |
Quenched and tempered | For maraging C300 the hardened condition is solution anneal at 815-830 °C, air cool, then age 3-6 h at 480 °C, giving about 1930 MPa tensile and 52-56 HRC with near-zero distortion instead of a conventional quench-and-temper cycle. | 1,860 | 1,930 | 8 | 54 HRC | 3.1 % IACS |
solution annealed + 480 °C / 3–6 h, air cool | Final full-strength condition (~53 HRC, ~1950 MPa) for aerospace structure, tooling and rotor parts; minimal distortion during aging. | 1,900 | 1,965 | 8 | 53 HRC | 3.8 % IACS |
Cold worked (≈20–50 % reduction) then maraged 480 °C | Highest-strength route for wire, thin strip and springs; strength above 2100 MPa at the cost of ductility and toughness. | 2,050 | 2,120 | 5 | 55 HRC | — |
What is C300-CR?
C300-CR is C300 supplied in the CR condition — thin sheet and strip with smooth surface and light cold work; formed to shape then aged (weld first, age last). C300-CR has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 93% of steel grades. Elongation at break is 7% and the elastic modulus is 186 GPa (27 Msi). C300-CR has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,413°C (2,575 °F). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 78/100, better than 95% of steel grades
- High strength — 1,050 MPa (152 ksi), better than 93% of steel grades
- Good corrosion resistance — 22/100, better than 90% of steel grades
- Readily welded — 75/100, better than 76% of steel grades
Limitations
- High embodied carbon — 7 kg CO₂/kg, worse than 99% of steel grades
- Poor heat conductor — 19.5 W/m·K (11.3 BTU/hr·ft·°F), worse than 97% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
C300-CR properties
Typical room-temperature values for C300-CR; 22 are specific to this condition. Other listed values are C300 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C300-CR has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,413°C (2,575 °F).
Mechanical16
C300-CR has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 93% of steel grades. Elongation at break is 7% and the elastic modulus is 186 GPa (27 Msi).
Thermal6
C300-CR is rated for continuous service to 400°C (752 °F). It conducts heat at 19.5 W/m·K (11.3 BTU/hr·ft·°F), worse than 97% of steel grades. Thermal expansion is 10.1 µm/m·K (5.61 µin/in·°F).
Electrical3
C300-CR conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of C300-CR takes about 105 MJ of energy and emits 7 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 20%.
Manufacturability7
C300-CR's machinability is fair (45/100, worse than 65% of steel grades); weldability very good (75/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C300-CR
Is C300 easy to machine?
Machine in the annealed condition (~30 HRC) with sharp carbide tooling, rigid setups and generous coolant; it is gummy and work-hardens, so use positive rake, moderate speeds and heavy feeds — aged material at 53 HRC needs grinding or ceramic/CBN finishing.
Can C300 be welded?
Excellent weldability by GTAW/EB/laser with matching low-carbon filler, no preheat and low heat input; solution-anneal or at minimum re-age at 480 °C after welding to restore joint strength, and keep the weld area free of oil, moisture and hydrogen.
Can C300 be formed, bent or molded?
Form, bend, deep-draw or spin in the annealed state where ductility is 15–20 %; aging causes only ~0.05–0.1 % uniform shrinkage, so finished dimensions are predictable after heat treatment.
What surface finishes work on C300?
Not corrosion resistant — protect with nitriding (raises surface to 65+ HRC), hard chrome, electroless nickel, cadmium/zinc-nickel or phosphate plus paint; avoid embrittling acid pickling and always bake after electroplating to relieve hydrogen.
C300 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 |
|---|---|---|
| Cultra-low carbon is essential | ≤ 0.03 | 0.01 |
| Ni | 18 – 19 | 18.5 |
| Co | 8.5 – 9.5 | 9 |
| Moforms Ni3Mo on aging | 4.6 – 5.2 | 4.9 |
| Timain strength lever vs 18Ni-250 | 0.55 – 0.8 | 0.65 |
| Al | 0.05 – 0.15 | 0.1 |
| Si | ≤ 0.1 | 0.05 |
| Mn | ≤ 0.1 | 0.05 |
| P | ≤ 0.01 | 0.01 |
| S | ≤ 0.01 | 0 |
| Bgrain-boundary addition (optional) | ≤ 0 | 0 |
| Zroptional addition | ≤ 0.02 | 0.01 |
| Caoptional deoxidiser | ≤ 0.05 | 0.02 |
| Fe | balance | — |
C300-CR — frequently asked
What is C300-CR used for?
C300-CR is typically used for rocket motor cases, missile bodies, centrifuge rotors, aerospace structural fittings, die-casting dies and high-strength tooling and punches. In short: ultra-strong maraging steel.
What is the yield strength of C300-CR?
C300-CR has a typical yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is C300-CR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed condition (~30 HRC) with sharp carbide tooling, rigid setups and generous coolant; it is gummy and work-hardens, so use positive rake, moderate speeds and heavy feeds — aged material at 53 HRC needs grinding or ceramic/CBN finishing.
Can C300-CR be welded?
Yes — weldability is rated very good (75/100). Excellent weldability by GTAW/EB/laser with matching low-carbon filler, no preheat and low heat input; solution-anneal or at minimum re-age at 480 °C after welding to restore joint strength, and keep the weld area free of oil, moisture and hydrogen.
What surface finishes work on C300-CR?
Not corrosion resistant — protect with nitriding (raises surface to 65+ HRC), hard chrome, electroless nickel, cadmium/zinc-nickel or phosphate plus paint; avoid embrittling acid pickling and always bake after electroplating to relieve hydrogen.
Can C300-CR be formed, bent or molded?
Form, bend, deep-draw or spin in the annealed state where ductility is 15–20 %; aging causes only ~0.05–0.1 % uniform shrinkage, so finished dimensions are predictable after heat treatment.
What is the maximum service temperature of C300-CR?
C300-CR 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 C300-HR and C300 Aged?
HR is the default condition — mill hot-worked stock with scale and looser tolerances; solution anneal and age before use. Aged: final full-strength condition (~53 HRC, ~1950 MPa) for aerospace structure, tooling and rotor parts; minimal distortion during aging. Yield strength is 850 MPa in HR versus 1,900 MPa in Aged.
Can FabDigit make parts in C300-CR?
Yes — C300-CR 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
- AMS 6514 — Steel, Maraging, Bars, Forgings, Tubing and Rings, 18.5Ni-9.0Co-4.9Mo-0.65Ti — SAE International (2019)
- AMS 6521 — Maraging 300 Sheet, Strip and Plate — SAE International (2018)
- ASTM A538/A538M — Pressure Vessel Plates, Maraging Steels (Grade C, 18Ni-300) — ASTM (2018)
- ASM Specialty Handbook: Tool Materials / Maraging Steels chapter — ASM International (1995)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- VascoMax C300 maraging steel datasheet — Carpenter Technology / Latrobe (2021)
- MMPDS-2023 maraging steel allowables — Battelle/FAA (2023)
- GB/T 34474 / 00Ni18Co9Mo5TiAl (2017)
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.