Steel 18Ni(350) Maraging Steel SA+CW
Supply condition
UNS K93160 · AISI/SAE 18Ni350 · also Vascomax C350
SA+CW = sA + cold drawn/rolled
Cold-worked annealed stock for wire, thin strip and precision bar; cold work raises pre-age strength and slightly boosts final aged strength.
Values for the SA+CW condition
Other 18Ni(350) Maraging Steel tempers and conditions
18Ni(350) Maraging Steel is listed in 4 conditions; see the grade overview at 18Ni(350) Maraging Steel.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Soft as-supplied/annealed condition for machining, cold forming and welding before final aging. | 830 | 1,140 | 17 | 32 HRC | 25 W/m·K |
SA+CWThis page SA + cold drawn/rolled | Cold-worked annealed stock for wire, thin strip and precision bar; cold work raises pre-age strength and slightly boosts final aged strength. | 1,150 | 1,300 | 8 | 38 HRC | 3.4 % IACS |
Overaged / toughness-optimized age | Slightly overaged cycle trading ~150–250 MPa of strength for better ductility and K_IC in fracture-critical parts. | 2,100 | 2,200 | 9 | 53 HRC | 3.9 % IACS |
AgedDefault 480 °C / 3–6 h, air cooled | Standard delivered/final condition: peak ~2400 MPa strength with minimal distortion; pick when extreme static strength governs and toughness demands are moderate. | 2,320 | 2,400 | 7 | 56 HRC | 20 W/m·K |
What is 18Ni(350) Maraging Steel SA+CW?
18Ni(350) Maraging Steel SA+CW is 18Ni(350) Maraging Steel supplied in the SA+CW condition — cold-worked annealed stock for wire, thin strip and precision bar; cold work raises pre-age strength and slightly boosts final aged strength. 18Ni(350) Maraging Steel SA+CW has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 8% and the elastic modulus is 186 GPa (27 Msi). 18Ni(350) Maraging Steel SA+CW has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 96% of steel grades. It melts at 1,413°C (2,575 °F). Aged is the default condition FabDigit quotes; SA+CW is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- High strength — 1,150 MPa (167 ksi), better than 94% of steel grades
- Good corrosion resistance — 28/100, better than 94% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- High embodied carbon — 6.5 kg CO₂/kg, worse than 98% of steel grades
- Poor heat conductor — 19 W/m·K (11 BTU/hr·ft·°F), worse than 97% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Low electrical conductivity — 3.4 % IACS, worse than 86% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
18Ni(350) Maraging Steel SA+CW properties
Typical room-temperature values for 18Ni(350) Maraging Steel SA+CW; 23 are specific to this condition. Other listed values are 18Ni(350) Maraging Steel reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
18Ni(350) Maraging Steel SA+CW has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 96% of steel grades. It melts at 1,413°C (2,575 °F).
Mechanical15
18Ni(350) Maraging Steel SA+CW has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 8% and the elastic modulus is 186 GPa (27 Msi).
Thermal6
18Ni(350) Maraging Steel SA+CW is rated for continuous service to 300°C (572 °F). It conducts heat at 19 W/m·K (11 BTU/hr·ft·°F), worse than 97% of steel grades. Thermal expansion is 10.1 µm/m·K (5.61 µin/in·°F).
Electrical3
18Ni(350) Maraging Steel SA+CW conducts electricity at 3.4 % IACS, worse than 86% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of 18Ni(350) Maraging Steel SA+CW takes about 90 MJ of energy and emits 6.5 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 20%.
Manufacturability8
18Ni(350) Maraging Steel SA+CW's machinability is fair (38/100, worse than 80% of steel grades); weldability very good (70/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 18Ni(350) Maraging Steel SA+CW
Is 18Ni(350) Maraging Steel easy to machine?
Rough-machine in the annealed condition (≈50 % of 1212) leaving ~0.05 % growth allowance for aging; aged 54–58 HRC material needs CBN/ceramic tooling, grinding or EDM.
Can 18Ni(350) Maraging Steel be welded?
GTAW/EBW/laser with matching filler, no preheat, low heat input on clean solution-annealed material; re-age at 480 °C after welding to restore joint strength (soft reverted-austenite zone otherwise).
Can 18Ni(350) Maraging Steel be formed, bent or molded?
Cold form, bend and deep-draw only in the solution-annealed state; hot work 1150–900 °C, then solution anneal at 815 °C before aging — aged parts are effectively non-formable.
What surface finishes work on 18Ni(350) Maraging Steel?
Not anodizable; use cadmium, electroless nickel or hard chrome plating with a 190 °C hydrogen-relief bake, or passivate/paint; vacuum-melted stock polishes to a fine mold finish and nitrides well.
18Ni(350) Maraging Steel 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 |
|---|---|---|
| Ni | 17.5 – 19 | 18.5 |
| Co | 11.5 – 12.5 | 12 |
| Mo | 4.6 – 5.2 | 4.9 |
| Tiprimary strengthener for 350 grade | 1.3 – 1.6 | 1.45 |
| Al | 0.05 – 0.15 | 0.1 |
| C | ≤ 0.03 | 0.01 |
| Si | ≤ 0.1 | — |
| Mn | ≤ 0.1 | — |
| P | ≤ 0.01 | — |
| S | ≤ 0.01 | — |
| Boptional grain-refining addition | ≤ 0 | — |
| Zroptional | ≤ 0.02 | — |
| Caoptional | ≤ 0.05 | — |
| Fe | balance | — |
18Ni(350) Maraging Steel SA+CW — frequently asked
What is 18Ni(350) Maraging Steel SA+CW used for?
18Ni(350) Maraging Steel SA+CW is typically used for rocket motor casings, high-strength shafts and aerospace fasteners. In short: strongest 18Ni maraging grade; 2400 MPa tensile, 56 HRC; low ductility at 7% elongation.
What is the yield strength of 18Ni(350) Maraging Steel SA+CW?
18Ni(350) Maraging Steel SA+CW has a typical yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is 18Ni(350) Maraging Steel SA+CW easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Rough-machine in the annealed condition (≈50 % of 1212) leaving ~0.05 % growth allowance for aging; aged 54–58 HRC material needs CBN/ceramic tooling, grinding or EDM.
Can 18Ni(350) Maraging Steel SA+CW be welded?
Yes — weldability is rated very good (70/100). GTAW/EBW/laser with matching filler, no preheat, low heat input on clean solution-annealed material; re-age at 480 °C after welding to restore joint strength (soft reverted-austenite zone otherwise).
What surface finishes work on 18Ni(350) Maraging Steel SA+CW?
Not anodizable; use cadmium, electroless nickel or hard chrome plating with a 190 °C hydrogen-relief bake, or passivate/paint; vacuum-melted stock polishes to a fine mold finish and nitrides well.
Can 18Ni(350) Maraging Steel SA+CW be formed, bent or molded?
Cold form, bend and deep-draw only in the solution-annealed state; hot work 1150–900 °C, then solution anneal at 815 °C before aging — aged parts are effectively non-formable.
What is the maximum service temperature of 18Ni(350) Maraging Steel SA+CW?
18Ni(350) Maraging Steel SA+CW is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 18Ni(350) Maraging Steel Aged and 18Ni(350) Maraging Steel-SA?
Aged is the default condition — standard delivered/final condition: peak ~2400 MPa strength with minimal distortion; pick when extreme static strength governs and toughness demands are moderate. SA: soft as-supplied/annealed condition for machining, cold forming and welding before final aging. Yield strength is 2,320 MPa in Aged versus 830 MPa in SA.
Sources
- AMS 6515 — Steel bars, forgings, tubing 18Ni-12Co-5Mo (maraging 350) — SAE International (2017)
- ASTM A538/A538M — Pressure vessel plates, alloy steel, precipitation hardening (18Ni maraging Grades A/B/C) — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Maraging Steels) — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- VascoMax C350 / Marval 18 maraging steel datasheet — Carpenter Technology / Aubert & Duval (2022)
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.