Nickel Alloy M30H-ST (Solution annealed)
Heat-treated state
UNS J24030 · ASTM A494 M30H
Softest condition, used to ease rough machining of complex castings before final age hardening.
Values for the ST condition
Other M30H tempers and conditions
M30H is listed in 3 conditions; see the grade overview at M30H.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STThis page Solution annealed | Softest condition, used to ease rough machining of complex castings before final age hardening. | 300 | 540 | 25 | 180 HB | 3 % IACS |
As fabricated | Pick when only moderate strength is needed and the part will be machined before any aging. | 330 | 570 | 20 | 14 HRC | 2.7 % IACS |
HTDefault Solution treated and age hardened (≈595 °C precipitation treatment) per… | Standard commercial supply condition — full strength and hardness for pump/valve wear parts in seawater. | 520 | 740 | 15 | 30 HRC | — |
What is M30H-ST?
M30H-ST is M30H heat treated to ST — softest condition, used to ease rough machining of complex castings before final age hardening. M30H-ST has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 25% and the elastic modulus is 172 GPa (24.9 Msi). M30H-ST has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 52% of nickel alloy grades. It melts at 1,180°C (2,156 °F). HT is the default condition FabDigit quotes; ST is available on request or by drawing note.
Advantages
- Easy to machine — 32/100, better than 95% of nickel alloy grades
- High electrical conductivity — 3 % IACS, better than 87% of nickel alloy grades
- Conducts heat well — 18.5 W/m·K (10.7 BTU/hr·ft·°F), better than 86% of nickel alloy grades
- Low embodied carbon — 11 kg CO₂/kg, better than 85% of nickel alloy grades
Limitations
- Low stiffness — 172 GPa (24.9 Msi), worse than 90% of nickel alloy grades
- Limited service temperature — 480°C (896 °F), worse than 82% of nickel alloy grades
- Low strength — 300 MPa (43.5 ksi), worse than 78% of nickel alloy grades
- Difficult to weld — 30/100, worse than 78% of nickel alloy grades
- Limited formability — 20/100, worse than 75% of nickel alloy grades
M30H-ST properties
Typical room-temperature values for M30H-ST; 22 are specific to this condition. Other listed values are M30H reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
M30H-ST has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 52% of nickel alloy grades. It melts at 1,180°C (2,156 °F).
Mechanical13
M30H-ST has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 25% and the elastic modulus is 172 GPa (24.9 Msi).
Thermal6
M30H-ST is rated for continuous service to 480°C (896 °F). It conducts heat at 18.5 W/m·K (10.7 BTU/hr·ft·°F), better than 86% of nickel alloy grades. Thermal expansion is 13.7 µm/m·K (7.61 µin/in·°F).
Electrical3
M30H-ST conducts electricity at 3 % IACS, better than 87% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 61% of nickel alloy grades.
Sustainability4
Producing a kilogram of M30H-ST takes about 130 MJ of energy and emits 11 kg of CO₂ — less than 87% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
M30H-ST's machinability is poor (32/100, better than 95% of nickel alloy grades); weldability poor (30/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M30H-ST
Is M30H easy to machine?
Rough-machine in the solution-treated state; when aged use rigid setups, positive-rake carbide, low speed (~15–25 m/min) and heavy feed with flood coolant to beat work hardening and abrasive silicide.
Can M30H be welded?
Weld only when necessary — high Si makes the alloy hot-crack sensitive; preheat 150–260 °C, use Ni-Cu (ERNiCu-7 / Monel 60) filler, low heat input, and re-age after repair.
Can M30H be formed, bent or molded?
Sand or investment casting alloy with good fluidity from the Si content; feed heavy sections generously and allow ~2 % pattern shrinkage — it is not cold-formable.
What surface finishes work on M30H?
Pickle/passivate to remove casting scale; takes a good mechanical polish and accepts electroless nickel or hard chrome for extra wear resistance — anodizing does not apply.
M30H 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 |
|---|---|---|
| Cu | 27 – 33 | 30 |
| Siage-hardening element (Ni-Si precipitates) | 2.7 – 3.7 | 3.2 |
| Fe | ≤ 3.5 | 2 |
| Mn | ≤ 1.5 | 0.8 |
| C | ≤ 0.3 | 0.2 |
| S | ≤ 0.03 | 0.01 |
| Niremainder per ASTM A494; Ni + Co may be reported together | ≥ 60 (balance) | — |
M30H-ST — frequently asked
What is M30H-ST used for?
M30H-ST is typically used for marine propeller hubs, pump shaft sleeves and seawater valve trim. In short: strongest cast Monel grade; si-hardened for wear duty; poor weldability, high strength.
What is the yield strength of M30H-ST?
M30H-ST has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 78% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is M30H-ST easy to machine?
Not especially — machinability is rated poor (32/100, better than 95% of nickel alloy grades). Rough-machine in the solution-treated state; when aged use rigid setups, positive-rake carbide, low speed (~15–25 m/min) and heavy feed with flood coolant to beat work hardening and abrasive silicide.
Can M30H-ST be welded?
Not readily — weldability is rated poor (30/100). Weld only when necessary — high Si makes the alloy hot-crack sensitive; preheat 150–260 °C, use Ni-Cu (ERNiCu-7 / Monel 60) filler, low heat input, and re-age after repair.
What surface finishes work on M30H-ST?
Pickle/passivate to remove casting scale; takes a good mechanical polish and accepts electroless nickel or hard chrome for extra wear resistance — anodizing does not apply.
Can M30H-ST be formed, bent or molded?
Sand or investment casting alloy with good fluidity from the Si content; feed heavy sections generously and allow ~2 % pattern shrinkage — it is not cold-formable.
What is the maximum service temperature of M30H-ST?
M30H-ST is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between M30H-HT and M30H-ST?
HT is the default condition — standard commercial supply condition — full strength and hardness for pump/valve wear parts in seawater. ST: softest condition, used to ease rough machining of complex castings before final age hardening. Yield strength is 520 MPa in HT versus 300 MPa in ST.
Sources
- ASTM A494/A494M — Castings, Nickel and Nickel Alloy — ASTM International (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 15 — Casting (nickel alloy castings) — ASM International (2008)
- Nickel-copper (Monel-type) casting alloy datasheets — Nickel Institute / foundry producers (2020)
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.