Steel FeNi42 1/2H
Supply condition
UNS K94200, K94100 · ASTM F30 · EN 1.3917 · GB 4J42 · also Alloy 42
1/2H = half hard
Standard half-hard strip/wire for stamped lead frames, springy contacts and parts needing higher yield without final anneal.
Values for the 1/2H condition
Other FeNi42 tempers and conditions
FeNi42 is listed in 6 conditions; see the grade overview at FeNi42.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault bright/hydrogen annealed, fully soft | Default stocked condition for lead frames, deep-drawn caps and glass-to-metal seal parts needing maximum ductility and stable CTE. | 300 | 540 | 33 | 140 HB | — |
Quarter hard | Pick when slightly stiffer strip is needed for stamping flatness while retaining useful bend ductility. | 450 | 620 | 18 | 170 HB | 2.5 % IACS |
Cold drawn | Standard bar/rod supply condition for machined seal bodies and headers; anneal after rough machining to restore CTE stability. | 560 | 690 | 12 | 14 HRC | 2.5 % IACS |
1/2HThis page Half hard | Standard half-hard strip/wire for stamped lead frames, springy contacts and parts needing higher yield without final anneal. | 580 | 700 | 10 | 205 HB | — |
Full hard | Maximum strength/stiffness strip for flat springs, shims and diaphragms where formability is not required. | 780 | 860 | 3 | 28 HRC | 2.4 % IACS |
Spring hard | Choose for wire and thin strip springs where high elastic limit and dimensional stability are needed. | 880 | 950 | 2 | 31 HRC | 2.4 % IACS |
What is FeNi42 1/2H?
FeNi42 1/2H is FeNi42 supplied in the 1/2H condition — standard half-hard strip/wire for stamped lead frames, springy contacts and parts needing higher yield without final anneal. FeNi42 1/2H has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 75% of steel grades. Elongation at break is 10% and the elastic modulus is 148 GPa (21.5 Msi). FeNi42 1/2H has a density of 8.12 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F). Annealed is the default condition FabDigit quotes; 1/2H is available on request or by drawing note.
Advantages
- Good corrosion resistance — 30/100, better than 95% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 580 MPa (84.1 ksi), better than 75% of steel grades
Limitations
- Poor heat conductor — 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 100% of steel grades
- High embodied carbon — 7 kg CO₂/kg, worse than 99% of steel grades
- Low stiffness — 148 GPa (21.5 Msi), worse than 98% of steel grades
- Low electrical conductivity — 2.5 % IACS, worse than 97% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
FeNi42 1/2H properties
Typical room-temperature values for FeNi42 1/2H; 15 are specific to this condition. Other listed values are FeNi42 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
FeNi42 1/2H has a density of 8.12 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
FeNi42 1/2H has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 75% of steel grades. Elongation at break is 10% and the elastic modulus is 148 GPa (21.5 Msi).
Thermal6
FeNi42 1/2H is rated for continuous service to 250°C (482 °F). It conducts heat at 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 100% of steel grades. Thermal expansion is 5.3 µm/m·K (2.94 µin/in·°F).
Electrical3
FeNi42 1/2H conducts electricity at 2.5 % IACS, worse than 97% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of FeNi42 1/2H takes about 100 MJ of energy and emits 7 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 30%.
Manufacturability8
FeNi42 1/2H's machinability is fair (36/100, worse than 81% of steel grades); weldability good (68/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with FeNi42 1/2H
Is FeNi42 easy to machine?
Gummy and work-hardening — use sharp, positive-rake carbide, rigid setups, heavy positive feed, low-to-moderate speed and generous sulphur-free coolant; avoid dwelling.
Can FeNi42 be welded?
Readily GTAW/laser/resistance welded to itself and to Kovar using matching or low-carbon Ni-Fe filler; keep joints free of C, S and Pb to avoid embrittlement and CTE shift.
Can FeNi42 be formed, bent or molded?
Annealed strip stamps and deep-draws like soft austenitic stainless; interstage anneal at 800–900 °C in dry H₂ and finish with a stabilising anneal to set the expansion curve.
What surface finishes work on FeNi42?
Not anodizable — protect with electroless/electrolytic Ni, then Sn, Ag or Au for soldering and corrosion resistance; oxidised (blued) surfaces are used before glass sealing.
FeNi42 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 controls CTE | 41 – 42.5 | 42 |
| C | ≤ 0.05 | 0.02 |
| Mn | ≤ 0.6 | 0.35 |
| Si | ≤ 0.3 | 0.15 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Crresidual | ≤ 0.25 | — |
| Coresidual/optional | ≤ 0.5 | — |
| Aldeoxidiser residual | ≤ 0.1 | — |
| Fe | balance | — |
FeNi42 1/2H — frequently asked
What is FeNi42 1/2H used for?
FeNi42 1/2H is typically used for IC lead frames, semiconductor package caps, glass-sealing components for silicon devices and bimetal strip layers. In short: silicon-matched expansion; standard lead-frame alloy; higher CTE than Invar 36.
What is the yield strength of FeNi42 1/2H?
FeNi42 1/2H has a typical yield strength of 580 MPa (84.1 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 75% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is FeNi42 1/2H easy to machine?
Not especially — machinability is rated fair (36/100, worse than 81% of steel grades). Gummy and work-hardening — use sharp, positive-rake carbide, rigid setups, heavy positive feed, low-to-moderate speed and generous sulphur-free coolant; avoid dwelling.
Can FeNi42 1/2H be welded?
Yes — weldability is rated good (68/100). Readily GTAW/laser/resistance welded to itself and to Kovar using matching or low-carbon Ni-Fe filler; keep joints free of C, S and Pb to avoid embrittlement and CTE shift.
What surface finishes work on FeNi42 1/2H?
Not anodizable — protect with electroless/electrolytic Ni, then Sn, Ag or Au for soldering and corrosion resistance; oxidised (blued) surfaces are used before glass sealing.
Can FeNi42 1/2H be formed, bent or molded?
Annealed strip stamps and deep-draws like soft austenitic stainless; interstage anneal at 800–900 °C in dry H₂ and finish with a stabilising anneal to set the expansion curve.
What is the maximum service temperature of FeNi42 1/2H?
FeNi42 1/2H is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between FeNi42 Annealed and FeNi42 Spring?
Annealed is the default condition — default stocked condition for lead frames, deep-drawn caps and glass-to-metal seal parts needing maximum ductility and stable CTE. Spring: choose for wire and thin strip springs where high elastic limit and dimensional stability are needed. Yield strength is 300 MPa in Annealed versus 880 MPa in Spring.
Sources
- ASTM F30 — Standard Specification for Iron-Nickel Sealing Alloys — ASTM International (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (controlled-expansion alloys) — ASM International (1990)
- Alloy 42 / Nilo 42 controlled expansion alloy datasheets — specialty Fe-Ni strip producers (2022)
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.