Steel Alloy 49 1/2H
Supply condition
UNS K94490 · ASTM A753 Type 1 · also Carpenter High Permeability 49, Hymu 49
1/2H = half hard
Intermediate strip temper for stamped parts needing more stiffness/springback control before the final magnetic anneal.
Values for the 1/2H condition
Other Alloy 49 tempers and conditions
Alloy 49 is listed in 4 conditions; see the grade overview at Alloy 49.
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 | — |
1/2HThis page 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 1/2H?
Alloy 49 1/2H is Alloy 49 supplied in the 1/2H condition — intermediate strip temper for stamped parts needing more stiffness/springback control before the final magnetic anneal. Alloy 49 1/2H has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 78% of steel grades. Elongation at break is 8% and the elastic modulus is 152 GPa (22 Msi). Alloy 49 1/2H 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; 1/2H is available on request or by drawing note.
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 620 MPa (89.9 ksi), better than 78% 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 stiffness — 152 GPa (22 Msi), worse than 98% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Low electrical conductivity — 3.5 % IACS, worse than 86% of steel grades
Alloy 49 1/2H properties
Typical room-temperature values for Alloy 49 1/2H; 23 are specific to this condition. Other listed values are Alloy 49 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Alloy 49 1/2H 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 1/2H has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 78% of steel grades. Elongation at break is 8% and the elastic modulus is 152 GPa (22 Msi).
Thermal5
Alloy 49 1/2H is rated for continuous service to 300°C (572 °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 1/2H conducts electricity at 3.5 % IACS, worse than 86% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of Alloy 49 1/2H 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 1/2H's machinability is fair (40/100, worse than 77% of steel grades); weldability good (60/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 49 1/2H
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.
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.
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 | — |
Alloy 49 1/2H — frequently asked
What is Alloy 49 1/2H used for?
Alloy 49 1/2H 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 1/2H?
Alloy 49 1/2H has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 78% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Alloy 49 1/2H easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% 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 1/2H be welded?
Yes — weldability is rated good (60/100). 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 1/2H?
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 1/2H 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 1/2H?
Alloy 49 1/2H 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 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.