Steel 4J50-Y2
Supply condition
GB 4J50 · UNS K95000
Y2 = half-hard
Compromise condition for springy stamped contacts and lead frames needing more stiffness than soft strip but still some bendability.
Values for the Y2 condition
Other 4J50 tempers and conditions
4J50 is listed in 6 conditions; see the grade overview at 4J50.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Bright / hydrogen (wet-H₂) annealed for glass sealing | Choose when a clean, decarburized, oxide-controlled surface is required for reliable glass-to-metal seals or for maximum ductility. | 250 | 480 | 38 | 120 HB | 4 % IACS |
MDefault Thermomechanically controlled processed | Standard stocked condition for stamping, deep drawing and glass-sealing parts; expansion curve is set by this final anneal. | 280 | 510 | 35 | 135 HB | 4 % IACS |
Stress relieved | Pick for dimensionally stable machined or formed parts where distortion during subsequent sealing/brazing must be avoided but full softening is unwanted. | 400 | 580 | 20 | 168 HB | 4 % IACS |
Y2This page Half-hard | Compromise condition for springy stamped contacts and lead frames needing more stiffness than soft strip but still some bendability. | 470 | 620 | 12 | 13 HRC | 4 % IACS |
Cold drawn | Standard condition for machined pins, eyelets and headers supplied as centreless-ground or drawn bar; anneal after machining to restore the expansion curve. | 520 | 660 | 12 | 14 HRC | 4 % IACS |
Hard | Highest strength and stiffness for flat springs, wire and thin strip; expansion match degrades until a final anneal is applied. | 640 | 760 | 4 | 22 HRC | 4 % IACS |
What is 4J50-Y2?
4J50-Y2 is 4J50 supplied in the Y2 condition — compromise condition for springy stamped contacts and lead frames needing more stiffness than soft strip but still some bendability. 4J50-Y2 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of steel grades. Elongation at break is 12% and the elastic modulus is 152 GPa (22 Msi). 4J50-Y2 has a density of 8.2 g/cm³ (0.296 lb/in³), heavier than 98% of steel grades. It melts at 1,425°C (2,597 °F). M is the default condition FabDigit quotes; Y2 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
Limitations
- Poor heat conductor — 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 99% of steel grades
- High embodied carbon — 7 kg CO₂/kg, worse than 99% of steel grades
- Low stiffness — 152 GPa (22 Msi), worse than 98% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Low electrical conductivity — 4 % IACS, worse than 83% of steel grades
4J50-Y2 properties
Typical room-temperature values for 4J50-Y2; 22 are specific to this condition. Other listed values are 4J50 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4J50-Y2 has a density of 8.2 g/cm³ (0.296 lb/in³), heavier than 98% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
4J50-Y2 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of steel grades. Elongation at break is 12% and the elastic modulus is 152 GPa (22 Msi).
Thermal6
4J50-Y2 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
4J50-Y2 conducts electricity at 4 % IACS, worse than 83% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of 4J50-Y2 takes about 80 MJ of energy and emits 7 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 20%.
Manufacturability7
4J50-Y2's machinability is fair (45/100, worse than 65% of steel grades); weldability good (65/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4J50-Y2
Is 4J50 easy to machine?
Machines like an austenitic stainless: gummy and work-hardening — use sharp positive-rake carbide, rigid setups, moderate speed with heavy feed and flood coolant; anneal after machining to restore the specified expansion curve.
Can 4J50 be welded?
Readily joined by TIG, resistance, electron-beam and laser welding with matching or Ni filler; keep the joint clean and low in carbon/sulphur to avoid hot cracking and seal leaks.
Can 4J50 be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, stamping, wire drawing); intermediate anneals near 850–950 °C in dry hydrogen or vacuum restore ductility.
What surface finishes work on 4J50?
Not anodizable — protect and prepare for soldering with electrolytic nickel, copper, silver or gold plating; a controlled thin oxide (wet-hydrogen or air pre-oxidation) is required before glass sealing.
4J50 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 the expansion coefficient | 49 – 51 | 50 |
| C | ≤ 0.05 | 0.03 |
| Si | ≤ 0.3 | 0.15 |
| Mn | ≤ 0.6 | 0.35 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Febalance, ≈50 % | balance | — |
4J50-Y2 — frequently asked
What is 4J50-Y2 used for?
4J50-Y2 is typically used for lead frames, relay parts and glass sealing components. In short: soft-glass sealing Fe-Ni; formable, poorly machining; moderate-expansion Invar relative.
What is the yield strength of 4J50-Y2?
4J50-Y2 has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 4J50-Y2 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machines like an austenitic stainless: gummy and work-hardening — use sharp positive-rake carbide, rigid setups, moderate speed with heavy feed and flood coolant; anneal after machining to restore the specified expansion curve.
Can 4J50-Y2 be welded?
Yes — weldability is rated good (65/100). Readily joined by TIG, resistance, electron-beam and laser welding with matching or Ni filler; keep the joint clean and low in carbon/sulphur to avoid hot cracking and seal leaks.
What surface finishes work on 4J50-Y2?
Not anodizable — protect and prepare for soldering with electrolytic nickel, copper, silver or gold plating; a controlled thin oxide (wet-hydrogen or air pre-oxidation) is required before glass sealing.
Can 4J50-Y2 be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, stamping, wire drawing); intermediate anneals near 850–950 °C in dry hydrogen or vacuum restore ductility.
What is the maximum service temperature of 4J50-Y2?
4J50-Y2 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 4J50-M and 4J50-Y?
M is the default condition — standard stocked condition for stamping, deep drawing and glass-sealing parts; expansion curve is set by this final anneal. Y: highest strength and stiffness for flat springs, wire and thin strip; expansion match degrades until a final anneal is applied. Yield strength is 280 MPa in M versus 640 MPa in Y.
Sources
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Low-Expansion Alloys) — ASM International (1990)
- Nilo/Glass-sealing alloy 50 & 52 data (Alloy 50 controlled-expansion strip) — Special Metals / Carpenter-type producer datasheets (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.