Steel 4J32-Y
Hardness band
GB 4J32 · UNS K93601 · JIS Super Invar
Y = hard, cold rolled ≥50 % reduction
Pick hard strip cold rolled ≥50 % for thin springs needing maximum strength and stiffness at 730 MPa yield; expansion rises slightly and stabilizing is required to restore it.
Values for the Y condition
Other 4J32 tempers and conditions
4J32 is listed in 5 conditions; see the grade overview at 4J32.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Default annealed delivery state from an 830 °C anneal with slow cooling: lowest expansion coefficient and highest ductility for later cold forming and finish machining. | 280 | 490 | 35 | 140 HB | — |
Annealed plus dimensional stabilization | Pick annealed plus stabilization (≈315 °C hold, slow cool) after rough machining for metrology instruments and optical bases needing long-term dimensional stability. | 300 | 500 | 33 | 150 HB | 2.2 % IACS |
Cold drawn | Choose cold drawn bar or wire for good size accuracy and surface quality with medium strength at 450 MPa yield, suited to parts machined directly from stock. | 450 | 620 | 20 | 11 HRC | 2.1 % IACS |
Half hard, cold rolled/drawn ≈20–30 % reduction | Use half-hard material cold worked about 20–30 % for strip and elastic supports that need 560 MPa yield while retaining some forming capability. | 560 | 700 | 12 | 20 HRC | 2.2 % IACS |
YThis page Hard, cold rolled ≥50 % reduction | Pick hard strip cold rolled ≥50 % for thin springs needing maximum strength and stiffness at 730 MPa yield; expansion rises slightly and stabilizing is required to restore it. | 730 | 830 | 5 | 27 HRC | 2.2 % IACS |
What is 4J32-Y?
4J32-Y is 4J32 heat treated to Y — pick hard strip cold rolled ≥50 % for thin springs needing maximum strength and stiffness at 730 MPa yield; expansion rises slightly and stabilizing is required to restore it. 4J32-Y has a yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Elongation at break is 5% and the elastic modulus is 150 GPa (21.8 Msi). 4J32-Y has a density of 8.15 g/cm³ (0.294 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F). M is the default condition FabDigit quotes; Y is available on request or by drawing note.
Advantages
- Good corrosion resistance — 28/100, better than 94% of steel grades
- High strength — 730 MPa (106 ksi), better than 83% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Poor heat conductor — 11.5 W/m·K (6.64 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 — 150 GPa (21.8 Msi), worse than 98% of steel grades
- Limited ductility — 5%, worse than 98% of steel grades
4J32-Y properties
Typical room-temperature values for 4J32-Y; 22 are specific to this condition. Other listed values are 4J32 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4J32-Y has a density of 8.15 g/cm³ (0.294 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
4J32-Y has a yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Elongation at break is 5% and the elastic modulus is 150 GPa (21.8 Msi).
Thermal6
4J32-Y is rated for continuous service to 150°C (302 °F). It conducts heat at 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 1.3 µm/m·K (0.722 µin/in·°F).
Electrical3
4J32-Y conducts electricity at 2.2 % IACS, worse than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of 4J32-Y takes about 115 MJ of energy and emits 8.5 kg of CO₂ — more than 100% of steel grades. Typical recycled content is 25%.
Manufacturability8
4J32-Y's machinability is poor (32/100, worse than 87% of steel grades); weldability good (55/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4J32-Y
Is 4J32 easy to machine?
Sticky and strongly work-hardening: use sharp positive-rake tooling, low speed with heavy feed and plentiful emulsion coolant. Stress-relieve after roughing and before finishing to hold dimensional stability.
Can 4J32 be welded?
TIG, electron-beam and laser welding are all usable with matching-composition filler, low heat input and no carbon contamination; anneal and stabilise after welding to restore low expansion and dimensional stability.
Can 4J32 be formed, bent or molded?
Ductility is excellent in the soft condition — deep drawing, bending and cold rolling to thin strip are routine; heavy cold work raises the expansion coefficient, so recrystallisation anneal to restore it.
What surface finishes work on 4J32?
Corrosion resistance is poor — protect with electroless nickel, chrome plating or paint; optical parts are usually nickel plated then polished. Cannot be anodised.
4J32 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 |
|---|---|---|
| Nimain element controlling low thermal expansion | 31.5 – 32.5 | 32 |
| Coshifts the expansion minimum to room temperature | 3.2 – 4.2 | 3.7 |
| C | ≤ 0.05 | 0.03 |
| Si | ≤ 0.3 | 0.15 |
| Mn | ≤ 0.6 | 0.35 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Fe | balance | — |
4J32-Y — frequently asked
What is 4J32-Y used for?
4J32-Y is typically used for precision instrument frames, optical benches and measuring standards. In short: lowest room-temperature expansion; super Invar equivalent; optical-bench stability grade.
What is the yield strength of 4J32-Y?
4J32-Y has a typical yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 4J32-Y easy to machine?
Not especially — machinability is rated poor (32/100, worse than 87% of steel grades). Sticky and strongly work-hardening: use sharp positive-rake tooling, low speed with heavy feed and plentiful emulsion coolant. Stress-relieve after roughing and before finishing to hold dimensional stability.
Can 4J32-Y be welded?
Yes — weldability is rated good (55/100). TIG, electron-beam and laser welding are all usable with matching-composition filler, low heat input and no carbon contamination; anneal and stabilise after welding to restore low expansion and dimensional stability.
What surface finishes work on 4J32-Y?
Corrosion resistance is poor — protect with electroless nickel, chrome plating or paint; optical parts are usually nickel plated then polished. Cannot be anodised.
Can 4J32-Y be formed, bent or molded?
Ductility is excellent in the soft condition — deep drawing, bending and cold rolling to thin strip are routine; heavy cold work raises the expansion coefficient, so recrystallisation anneal to restore it.
What is the maximum service temperature of 4J32-Y?
4J32-Y is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4J32-M and 4J32-Y?
M is the default condition — default annealed delivery state from an 830 °C anneal with slow cooling: lowest expansion coefficient and highest ductility for later cold forming and finish machining. Y: pick hard strip cold rolled ≥50 % for thin springs needing maximum strength and stiffness at 730 MPa yield; expansion rises slightly and stabilizing is required to restore it. Yield strength is 280 MPa in M versus 730 MPa in Y.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Low-Expansion Alloys) — ASM International (1990)
- Super Invar 32-5 Alloy Technical Datasheet — 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.