Steel Alloy 50 MagAnn
Heat-treated state
UNS K95000 · ASTM F30
MagAnn = magnetic anneal
Final anneal on finished parts to maximise permeability and minimise coercivity in relay and solenoid cores.
Values for the MagAnn condition
Other Alloy 50 tempers and conditions
Alloy 50 is listed in 7 conditions; see the grade overview at Alloy 50.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MagAnnThis page Magnetic anneal | Final anneal on finished parts to maximise permeability and minimise coercivity in relay and solenoid cores. | 200 | 480 | 42 | 128 HB | 4 % IACS |
ANNDefault Annealed | Standard stocked softened condition for stamping, drawing and glass sealing. | 250 | 520 | 38 | 145 HB | 3.8 % IACS |
Stress relieved | Removes forming stresses and stabilises dimensions/expansion before glass sealing without full softening. | 330 | 560 | 30 | 158 HB | 3.8 % IACS |
Quarter hard | Light temper rolling for flat, burr-free stamping of lead frames and contacts. | 450 | 620 | 18 | 10 HRC | 3.8 % IACS |
Cold drawn | Straight-length bar and wire for machined leads and pins; higher strength, needs stress relief before sealing. | 560 | 700 | 12 | 17 HRC | 3.8 % IACS |
Half hard | Medium temper for springy relay armatures and stamped parts that are not re-annealed. | 590 | 720 | 10 | 20 HRC | 3.8 % IACS |
Full hard | Maximum strength/springback condition for reeds and blanking; very limited bending, magnetics degraded until annealed. | 760 | 850 | 4 | 26 HRC | 3.8 % IACS |
What is Alloy 50 MagAnn?
Alloy 50 MagAnn is Alloy 50 heat treated to MagAnn — final anneal on finished parts to maximise permeability and minimise coercivity in relay and solenoid cores. Alloy 50 MagAnn has a yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 98% of steel grades. Elongation at break is 42% and the elastic modulus is 158 GPa (22.9 Msi). Alloy 50 MagAnn 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). ANN is the default condition FabDigit quotes; MagAnn is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 42%, better than 100% of steel grades
- Forms and bends easily — 92/100, better than 99% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Readily welded — 78/100, better than 78% of steel grades
Limitations
- High embodied carbon — 7 kg CO₂/kg, worse than 99% of steel grades
- Low strength — 200 MPa (29 ksi), worse than 98% of steel grades
- Poor heat conductor — 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 98% of steel grades
- Low stiffness — 158 GPa (22.9 Msi), worse than 97% of steel grades
- Difficult to machine — 30/100, worse than 89% of steel grades
Alloy 50 MagAnn properties
Typical room-temperature values for Alloy 50 MagAnn; 21 are specific to this condition. Other listed values are Alloy 50 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Alloy 50 MagAnn 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).
Mechanical16
Alloy 50 MagAnn has a yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 98% of steel grades. Elongation at break is 42% and the elastic modulus is 158 GPa (22.9 Msi).
Thermal6
Alloy 50 MagAnn is rated for continuous service to 400°C (752 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 98% of steel grades. Thermal expansion is 9.6 µm/m·K (5.33 µin/in·°F).
Electrical3
Alloy 50 MagAnn conducts electricity at 4 % IACS, worse than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of Alloy 50 MagAnn takes about 90 MJ of energy and emits 7 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 30%.
Manufacturability7
Alloy 50 MagAnn's machinability is poor (30/100, worse than 89% of steel grades); weldability very good (78/100); formability excellent (92/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 50 MagAnn
Is Alloy 50 easy to machine?
Gummy and work-hardening like austenitic stainless — use sharp positive-rake carbide, 25–45 m/min, heavy positive feed, rigid setup and flood coolant to avoid built-up edge.
Can Alloy 50 be welded?
Readily GTAW, laser and resistance welded with matching Fe-50Ni filler; keep heat input low and joints clean, avoid sulphur/lead contamination to prevent hot cracking.
Can Alloy 50 be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, fine-blanking, progressive-die stamping); anneal between heavy draws and stress-relieve before glass sealing.
What surface finishes work on Alloy 50?
No natural corrosion resistance — electroplate Ni, Ag, Sn or Au for service and solderability; for glass-to-metal seals, form a controlled wet-hydrogen/steam oxide layer instead of plating.
Alloy 50 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) content sets the expansion/permeability; per ASTM F30 Alloy 50 / GB/T 4J50 | 49 – 51 | 50 |
| Coresidual | ≤ 0.5 | — |
| C | ≤ 0.05 | 0.02 |
| Mn | ≤ 0.8 | 0.4 |
| Si | ≤ 0.3 | 0.15 |
| Crresidual | ≤ 0.25 | — |
| Aldeoxidiser residual | ≤ 0.1 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Febalance, ~49–50 % | balance | — |
Alloy 50 MagAnn — frequently asked
What is Alloy 50 MagAnn used for?
Alloy 50 MagAnn is typically used for lead frames, relay reeds, magnetic shielding components and glass sealing. In short: soft-magnetic Fe-Ni alloy; higher expansion than Invar; magnetic-anneal tempers available.
What is the yield strength of Alloy 50 MagAnn?
Alloy 50 MagAnn has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 98% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is Alloy 50 MagAnn easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Gummy and work-hardening like austenitic stainless — use sharp positive-rake carbide, 25–45 m/min, heavy positive feed, rigid setup and flood coolant to avoid built-up edge.
Can Alloy 50 MagAnn be welded?
Yes — weldability is rated very good (78/100). Readily GTAW, laser and resistance welded with matching Fe-50Ni filler; keep heat input low and joints clean, avoid sulphur/lead contamination to prevent hot cracking.
What surface finishes work on Alloy 50 MagAnn?
No natural corrosion resistance — electroplate Ni, Ag, Sn or Au for service and solderability; for glass-to-metal seals, form a controlled wet-hydrogen/steam oxide layer instead of plating.
Can Alloy 50 MagAnn be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, fine-blanking, progressive-die stamping); anneal between heavy draws and stress-relieve before glass sealing.
What is the maximum service temperature of Alloy 50 MagAnn?
Alloy 50 MagAnn 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 Alloy 50-ANN and Alloy 50-FH?
ANN is the default condition — standard stocked softened condition for stamping, drawing and glass sealing. FH: maximum strength/springback condition for reeds and blanking; very limited bending, magnetics degraded until annealed. Yield strength is 250 MPa in ANN versus 760 MPa in FH.
Sources
- ASTM F30 — Standard Specification for Iron-Nickel Sealing Alloys — ASTM International (2018)
- GB/T 15018 / GB/T 14986 4J50 (Fe-Ni ) (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Fe-Ni low-expansion & soft magnetic alloys) — ASM International (1990)
- Nilo alloy 50 / Sealing Alloy 50 technical data — Special Metals / Carpenter Technology (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.