Steel 4J32-CD (Cold drawn)
Supply condition
GB 4J32 · UNS K93601 · JIS Super Invar
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.
Values for the CD 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 |
CDThis page 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 |
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-CD?
4J32-CD is 4J32 supplied in the CD condition — 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. 4J32-CD has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of steel grades. Elongation at break is 20% and the elastic modulus is 150 GPa (21.8 Msi). 4J32-CD 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; CD is available on request or by drawing note.
Advantages
- Good corrosion resistance — 28/100, better than 94% 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 W/m·K (6.36 BTU/hr·ft·°F), worse than 99% of steel grades
- Low electrical conductivity — 2.1 % IACS, 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
4J32-CD properties
Typical room-temperature values for 4J32-CD; 23 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-CD 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-CD has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of steel grades. Elongation at break is 20% and the elastic modulus is 150 GPa (21.8 Msi).
Thermal6
4J32-CD is rated for continuous service to 150°C (302 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 0.9 µm/m·K (0.5 µin/in·°F).
Electrical3
4J32-CD conducts electricity at 2.1 % IACS, worse than 99% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of 4J32-CD 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-CD's machinability is fair (38/100, worse than 80% 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 4J32-CD
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-CD — frequently asked
What is 4J32-CD used for?
4J32-CD 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-CD?
4J32-CD has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 4J32-CD easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% 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-CD be welded?
Yes — weldability is rated good (60/100). 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-CD?
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-CD 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-CD?
4J32-CD 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.