Steel Alloy 49
UNS K94490 · ASTM A753 Type 1 · also Carpenter High Permeability 49, Hymu 49
A 49% nickel-balance-iron soft magnetic alloy offering very high initial and maximum permeability with low coercivity, chosen for sensitive magnetic shielding and transformer cores where signal fidelity at low field strengths matters.
Reference datasheet — Alloy 49 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
Alloy 49 tempers and conditions
Alloy 49 is supplied in 4 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard supply and final condition for magnetic parts: soft, ductile, maximum permeability and lowest coercivity. | 220 | 530 | 38 | 120 HB | — |
Half hard | Intermediate strip temper for stamped parts needing more stiffness/springback control before the final magnetic anneal. | 620 | 750 | 8 | 16 HRC | 3.5 % IACS |
Cold drawn | Cold-drawn rod and wire for machined cores, pole pieces and relay armatures that will be annealed after machining. | 650 | 780 | 10 | 19 HRC | 3.5 % IACS |
Hardened | Maximum-strength as-rolled strip for springy or high-stiffness parts; magnetic properties are poor until a final anneal is performed. | 850 | 950 | 3 | 25 HRC | — |
What is Alloy 49?
A 49% nickel-balance-iron soft magnetic alloy offering very high initial and maximum permeability with low coercivity, chosen for sensitive magnetic shielding and transformer cores where signal fidelity at low field strengths matters. Alloy 49 has a density of 8.25 g/cm³ (0.298 lb/in³), heavier than 98% of steel grades. It melts at 1,425°C (2,597 °F). Alloy 49 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 98% of steel grades. Elongation at break is 38% and the elastic modulus is 150 GPa (21.8 Msi).
What is Alloy 49 used for?
- magnetic shielding
- instrument transformer cores
- current transformers
- relay components
- sensitive magnetic sensors
Advantages
- Ductile — tolerates forming and impact — 38%, better than 98% of steel grades
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Poor heat conductor — 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 99% of steel grades
- High embodied carbon — 8.5 kg CO₂/kg, worse than 99% of steel grades
- Low strength — 220 MPa (31.9 ksi), worse than 98% of steel grades
- Low stiffness — 150 GPa (21.8 Msi), worse than 98% of steel grades
- Low electrical conductivity — 3.6 % IACS, worse than 85% of steel grades
Alloy 49 properties
Typical room-temperature values for Alloy 49-ANN; bars are the position among steel grades.
Physical3
Alloy 49 has a density of 8.25 g/cm³ (0.298 lb/in³), heavier than 98% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
Alloy 49 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 98% of steel grades. Elongation at break is 38% and the elastic modulus is 150 GPa (21.8 Msi).
Thermal5
Alloy 49 is rated for continuous service to 480°C (896 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 9.5 µm/m·K (5.28 µin/in·°F).
Electrical3
Alloy 49 conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of Alloy 49 takes about 120 MJ of energy and emits 8.5 kg of CO₂ — more than 100% of steel grades. Typical recycled content is 30%.
Manufacturability8
Alloy 49's machinability is fair (35/100, worse than 84% of steel grades); weldability very good (70/100); formability excellent (85/100).
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. Alloy 49 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Alloy 49
Is Alloy 49 easy to machine?
Gummy and work-hardening — use sharp positive-rake carbide, low speed with heavy feed, rigid setup and flood coolant; leave stock for the final hydrogen anneal since machining stress kills permeability.
Can Alloy 49 be welded?
Readily GTAW/resistance/laser welded with matching or Ni filler and low heat input; every welded assembly must be magnetically annealed afterwards.
Can Alloy 49 be formed, bent or molded?
Excellent deep-drawing and stamping behaviour in the annealed temper; design for a stress-free final anneal at 1050–1175 °C in dry hydrogen with controlled cooling.
Alloy 49 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 |
|---|---|---|
| NiNi + Co counted together in ASTM A753 Type 1 | 47 – 50 | 48.5 |
| Mn | 0.3 – 0.8 | 0.5 |
| Si | 0.1 – 0.35 | 0.2 |
| Ckept low for magnetic softness | ≤ 0.05 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| P | ≤ 0.02 | 0.01 |
| Fe | balance |
What surface finishes work on Alloy 49?
Not anodizable; protect with electroless nickel, tin or zinc plating, or lacquer — plating should follow the magnetic anneal to avoid hydrogen and stress effects.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel Alloy 49 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- K94490
- ASTM
- A753 Type 1
- Trade names
- Carpenter High Permeability 49Hymu 49
How much does Alloy 49 cost?
Alloy 49 is a high-cost steel ($$$$), pricier than about 78% 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.
Alloy 49 — frequently asked
What is Alloy 49 used for?
Alloy 49 is typically used for magnetic shielding, instrument transformer cores, current transformers, relay components and sensitive magnetic sensors. In short: highest-permeability Fe-Ni alloy; low-field shielding grade; needs final hydrogen anneal.
What is the yield strength of Alloy 49?
Alloy 49 has a typical yield strength of 220 MPa (31.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 98% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Alloy 49 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Gummy and work-hardening — use sharp positive-rake carbide, low speed with heavy feed, rigid setup and flood coolant; leave stock for the final hydrogen anneal since machining stress kills permeability.
Can Alloy 49 be welded?
Yes — weldability is rated very good (70/100). Readily GTAW/resistance/laser welded with matching or Ni filler and low heat input; every welded assembly must be magnetically annealed afterwards.
What surface finishes work on Alloy 49?
Not anodizable; protect with electroless nickel, tin or zinc plating, or lacquer — plating should follow the magnetic anneal to avoid hydrogen and stress effects.
Can Alloy 49 be formed, bent or molded?
Excellent deep-drawing and stamping behaviour in the annealed temper; design for a stress-free final anneal at 1050–1175 °C in dry hydrogen with controlled cooling.
What is the maximum service temperature of Alloy 49?
Alloy 49 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 Alloy 49-ANN and Alloy 49-H?
ANN is the default condition — standard supply and final condition for magnetic parts: soft, ductile, maximum permeability and lowest coercivity. H: maximum-strength as-rolled strip for springy or high-stiffness parts; magnetic properties are poor until a final anneal is performed. Yield strength is 220 MPa in ANN versus 850 MPa in H.
How much does Alloy 49 cost?
Alloy 49 is a high-cost steel ($$$$), pricier than about 78% 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.
Sources
- ASTM A753 — Standard Specification for Wrought Nickel-Iron Soft Magnetic Alloys — ASTM International (2019)
- GB/T 15005 (1J50 ) (2017)
- High Permeability 49 Alloy technical datasheet — Carpenter Technology (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (soft magnetic alloys) — ASM International (1990)
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.