Steel 4J42 Annealed
Temper · default condition
GB 4J42 · UNS K94100
Standard stocked condition for glass sealing, deep drawing and lead-frame stamping; gives the specified low, stable expansion coefficient.
Values for the Annealed condition
Other 4J42 tempers and conditions
4J42 is listed in 6 conditions; see the grade overview at 4J42.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefaultThis page bright/hydrogen annealed soft condition (strip, plate, bar) | Standard stocked condition for glass sealing, deep drawing and lead-frame stamping; gives the specified low, stable expansion coefficient. | 285 | 510 | 35 | 145 HB | — |
Hot rolled | Mill condition for thick plate and forgings; requires stress-relief/annealing before precision machining or sealing. | 300 | 520 | 30 | 155 HB | 2.5 % IACS |
Cold Rolled 1/4 Hard | Pick when annealed strip is too soft to feed/stamp cleanly but good ductility is still needed. | 430 | 580 | 20 | 175 HB | 2.5 % IACS |
Cold drawn | Standard supply state for bar and wire that will be machined into pins, headers and eyelets. | 490 | 630 | 15 | 11 HRC | 2.4 % IACS |
Cold Rolled 1/2 Hard | Use for spring-back-controlled formed parts and stiffer stamped frames/covers. | 560 | 660 | 10 | 17 HRC | 2.5 % IACS |
Cold Rolled Hard | Highest strength and flatness for thin foil, shims and spring-type contacts; must be annealed if low-expansion accuracy after forming is critical. | 720 | 810 | 3 | 27 HRC | 2.5 % IACS |
What is 4J42 Annealed?
4J42 Annealed is 4J42 in the Annealed temper — standard stocked condition for glass sealing, deep drawing and lead-frame stamping; gives the specified low, stable expansion coefficient. 4J42 Annealed has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 89% of steel grades. Elongation at break is 35% and the elastic modulus is 145 GPa (21 Msi). 4J42 Annealed 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).
Advantages
- Ductile — tolerates forming and impact — 35%, better than 97% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- Good corrosion resistance — 28/100, better than 94% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Poor heat conductor — 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 99% of steel grades
- Low stiffness — 145 GPa (21 Msi), worse than 98% of steel grades
- High embodied carbon — 6.6 kg CO₂/kg, worse than 98% of steel grades
- Low electrical conductivity — 2.5 % IACS, worse than 97% of steel grades
- Low strength — 285 MPa (41.3 ksi), worse than 89% of steel grades
4J42 Annealed properties
Typical room-temperature values for 4J42 Annealed; 13 are specific to this condition. Other listed values are 4J42 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4J42 Annealed 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
4J42 Annealed has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 89% of steel grades. Elongation at break is 35% and the elastic modulus is 145 GPa (21 Msi).
Thermal5
4J42 Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 5.3 µm/m·K (2.94 µin/in·°F).
Electrical3
4J42 Annealed conducts electricity at 2.5 % IACS, worse than 97% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of 4J42 Annealed takes about 70 MJ of energy and emits 6.6 kg of CO₂ — more than 97% of steel grades. Typical recycled content is 35%.
Manufacturability7
4J42 Annealed'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. Confirm any required mill or lot documentation when quoting.
Working with 4J42 Annealed
Is 4J42 easy to machine?
Gummy and work-hardening like austenitic stainless: use sharp positive-rake carbide, rigid setups, low speed/high feed and flood coolant; avoid dwelling to prevent glazing.
Can 4J42 be welded?
Resistance, laser and GTAW welding are routine with matching Fe-42Ni filler; keep heat input low and interpass clean, since carbon/sulfur pickup causes porosity and gas leakage in seals.
Can 4J42 be formed, bent or molded?
Excellent deep-drawing and stamping in the annealed state; interstage anneal for severe draws and always re-anneal (with controlled H₂/vacuum cycle) before glass sealing to restore expansion accuracy.
What surface finishes work on 4J42?
Not anodizable — protect with electroplated Ni, Ni+Au, Ag or Sn; oxidize the surface in a controlled wet-H₂/air cycle before glass-to-metal sealing to form the adherent bonding oxide.
4J42 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 |
|---|---|---|
| Nicontrols expansion coefficient | 41.5 – 42.5 | 42 |
| C | ≤ 0.05 | 0.03 |
| Si | ≤ 0.3 | 0.15 |
| Mn | 0.2 – 0.6 | 0.4 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Crresidual | ≤ 0.1 | — |
| Curesidual | ≤ 0.2 | — |
| Fe | balance | — |
4J42 Annealed — frequently asked
What is 4J42 Annealed used for?
4J42 Annealed is typically used for IC lead frames, electronic component headers and glass-metal seals. In short: 42Ni lead-frame alloy; alloy 42 equivalent; soft-glass sealing strip.
What is the yield strength of 4J42 Annealed?
4J42 Annealed has a typical yield strength of 285 MPa (41.3 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 89% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 4J42 Annealed easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Gummy and work-hardening like austenitic stainless: use sharp positive-rake carbide, rigid setups, low speed/high feed and flood coolant; avoid dwelling to prevent glazing.
Can 4J42 Annealed be welded?
Yes — weldability is rated very good (70/100). Resistance, laser and GTAW welding are routine with matching Fe-42Ni filler; keep heat input low and interpass clean, since carbon/sulfur pickup causes porosity and gas leakage in seals.
What surface finishes work on 4J42 Annealed?
Not anodizable — protect with electroplated Ni, Ni+Au, Ag or Sn; oxidize the surface in a controlled wet-H₂/air cycle before glass-to-metal sealing to form the adherent bonding oxide.
Can 4J42 Annealed be formed, bent or molded?
Excellent deep-drawing and stamping in the annealed state; interstage anneal for severe draws and always re-anneal (with controlled H₂/vacuum cycle) before glass sealing to restore expansion accuracy.
What is the maximum service temperature of 4J42 Annealed?
4J42 Annealed 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 4J42 Annealed and 4J42 CR-H?
Annealed is the default condition — standard stocked condition for glass sealing, deep drawing and lead-frame stamping; gives the specified low, stable expansion coefficient. CR-H: highest strength and flatness for thin foil, shims and spring-type contacts; must be annealed if low-expansion accuracy after forming is critical. Yield strength is 285 MPa in Annealed versus 720 MPa in CR-H.
Sources
- ASM Handbook Vol. 2 — Properties of Controlled-Expansion Alloys (Alloy 42) — ASM International (1990)
- Alloy 42 / Nilo 42 controlled-expansion strip datasheet — Carpenter / Special Metals (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.