Nickel Alloy M30H-HT
Heat-treated state · default condition
UNS J24030 · ASTM A494 M30H
HT = 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.
Values for the HT 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 |
|---|---|---|---|---|---|---|
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 |
HTDefaultThis page 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-HT?
M30H-HT is M30H heat treated to HT — standard commercial supply condition — full strength and hardness for pump/valve wear parts in seawater. M30H-HT has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 740 MPa (107 ksi) — stronger than 76% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 172 GPa (24.9 Msi). M30H-HT 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).
Advantages
- High electrical conductivity — 2.5 % IACS, better than 85% of nickel alloy grades
- Low embodied carbon — 11 kg CO₂/kg, better than 85% of nickel alloy grades
- Conducts heat well — 17 W/m·K (9.82 BTU/hr·ft·°F), better than 84% of nickel alloy grades
- High strength — 520 MPa (75.4 ksi), better than 76% of nickel alloy grades
Limitations
- Low stiffness — 172 GPa (24.9 Msi), worse than 90% of nickel alloy grades
- Limited formability — 10/100, worse than 85% of nickel alloy grades
- Limited service temperature — 480°C (896 °F), worse than 82% of nickel alloy grades
- Difficult to weld — 25/100, worse than 82% of nickel alloy grades
- Limited ductility — 15%, worse than 81% of nickel alloy grades
M30H-HT properties
Typical room-temperature values for M30H-HT; 14 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-HT 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-HT has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 740 MPa (107 ksi) — stronger than 76% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 172 GPa (24.9 Msi).
Thermal6
M30H-HT is rated for continuous service to 480°C (896 °F). It conducts heat at 17 W/m·K (9.82 BTU/hr·ft·°F), better than 84% of nickel alloy grades. Thermal expansion is 13.7 µm/m·K (7.61 µin/in·°F).
Electrical3
M30H-HT conducts electricity at 2.5 % IACS, better than 85% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 51% of nickel alloy grades.
Sustainability4
Producing a kilogram of M30H-HT 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-HT's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability poor (25/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M30H-HT
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-HT — frequently asked
What is M30H-HT used for?
M30H-HT 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-HT?
M30H-HT has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 740 MPa (107 ksi) — stronger than 76% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is M30H-HT easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% 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-HT be welded?
Not readily — weldability is rated poor (25/100). 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-HT?
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-HT 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-HT?
M30H-HT 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.