Steel GX3Ni36 A+ST
Heat-treated state
EN 1.3961
A+ST = annealed, quenched, stress relieved 315 °C and stabilised 95 °C
Full metrology treatment: choose for gauges, masters and tooling that must hold dimensions for years.
Values for the A+ST condition
Other GX3Ni36 tempers and conditions
GX3Ni36 is listed in 5 conditions; see the grade overview at GX3Ni36.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest, most homogeneous condition; lowest and most reproducible expansion coefficient before final machining. | 205 | 425 | 30 | 120 HB | 2.2 % IACS |
A+STThis page Annealed, quenched, stress relieved 315 °C and stabilised 95 °C | Full metrology treatment: choose for gauges, masters and tooling that must hold dimensions for years. | 215 | 435 | 28 | 123 HB | 2.1 % IACS |
Hot isostatically pressed then annealed | Use for vacuum-tight or fatigue-critical castings where shrinkage porosity must be closed. | 225 | 470 | 35 | 125 HB | 2.1 % IACS |
Stress relieved | Pick when casting/weld residual stress must be cut before rough machining without changing strength much. | 235 | 445 | 27 | 128 HB | 2.1 % IACS |
FDefault As fabricated | Standard supply condition for rough castings that will be annealed/stabilised after rough machining. | 240 | 450 | 25 | 130 HB | 2.1 % IACS |
What is GX3Ni36 A+ST?
GX3Ni36 A+ST is GX3Ni36 heat treated to A+ST — full metrology treatment: choose for gauges, masters and tooling that must hold dimensions for years. GX3Ni36 A+ST has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 435 MPa (63.1 ksi) — weaker than 98% of steel grades. Elongation at break is 28% and the elastic modulus is 145 GPa (21 Msi). GX3Ni36 A+ST has a density of 8.1 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F). F is the default condition FabDigit quotes; A+ST is available on request or by drawing note.
Advantages
- Good corrosion resistance — 25/100, better than 92% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- 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 — 7 kg CO₂/kg, worse than 99% of steel grades
- Low strength — 215 MPa (31.2 ksi), worse than 98% of steel grades
- Low stiffness — 145 GPa (21 Msi), worse than 98% of steel grades
GX3Ni36 A+ST properties
Typical room-temperature values for GX3Ni36 A+ST; 22 are specific to this condition. Other listed values are GX3Ni36 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GX3Ni36 A+ST has a density of 8.1 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
GX3Ni36 A+ST has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 435 MPa (63.1 ksi) — weaker than 98% of steel grades. Elongation at break is 28% and the elastic modulus is 145 GPa (21 Msi).
Thermal6
GX3Ni36 A+ST is rated for continuous service to 200°C (392 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 1.4 µm/m·K (0.778 µin/in·°F).
Electrical3
GX3Ni36 A+ST conducts electricity at 2.1 % IACS, worse than 99% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of GX3Ni36 A+ST takes about 90 MJ of energy and emits 7 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 45%.
Manufacturability8
GX3Ni36 A+ST's machinability is poor (28/100, worse than 91% of steel grades); weldability good (58/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GX3Ni36 A+ST
Is GX3Ni36 easy to machine?
Gummy and work-hardening: use sharp positive-rake carbide, heavy flood coolant, low speed (~25–40 m/min) and constant feed to avoid rubbing; rough-machine, anneal, then finish.
Can GX3Ni36 be welded?
GTAW/EBW with matching Fe-36Ni filler, low heat input and clean joints; avoid sulphur/lead contamination (hot cracking) and re-anneal welds to restore low CTE.
Can GX3Ni36 be formed, bent or molded?
Sand or investment cast with generous risering and controlled pouring — melt is sluggish, gas- and hot-tear-sensitive; allow ~2 % shrinkage and machining stock.
What surface finishes work on GX3Ni36?
Polishes well for mould faces; corrosion protection by electroless nickel, chrome plating, paint or oiling — no anodising (ferrous).
GX3Ni36 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 |
|---|---|---|
| CGX3 designation = ≈0.03 % C | ≤ 0.05 | 0.03 |
| Sideoxidiser, raises CTE if high | ≤ 0.5 | 0.3 |
| Mn | ≤ 0.6 | 0.35 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| NiInvar composition; CTE minimum near 36 % Ni | 35 – 37 | 36 |
| Crresidual | ≤ 0.5 | — |
| Coresidual; deliberate Co additions give Super-Invar variants | ≤ 0.5 | — |
| Fe | balance | — |
GX3Ni36 A+ST — frequently asked
What is GX3Ni36 A+ST used for?
GX3Ni36 A+ST is typically used for composite/CFRP layup tooling, precision measuring instrument castings, mold bases requiring dimensional stability and cryogenic component castings. In short: cast Invar for tooling; weldable low-expansion casting; tough cast Fe-36Ni.
What is the yield strength of GX3Ni36 A+ST?
GX3Ni36 A+ST has a typical yield strength of 215 MPa (31.2 ksi) and a tensile strength of 435 MPa (63.1 ksi) — weaker than 98% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is GX3Ni36 A+ST easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Gummy and work-hardening: use sharp positive-rake carbide, heavy flood coolant, low speed (~25–40 m/min) and constant feed to avoid rubbing; rough-machine, anneal, then finish.
Can GX3Ni36 A+ST be welded?
Yes — weldability is rated good (58/100). GTAW/EBW with matching Fe-36Ni filler, low heat input and clean joints; avoid sulphur/lead contamination (hot cracking) and re-anneal welds to restore low CTE.
What surface finishes work on GX3Ni36 A+ST?
Polishes well for mould faces; corrosion protection by electroless nickel, chrome plating, paint or oiling — no anodising (ferrous).
Can GX3Ni36 A+ST be formed, bent or molded?
Sand or investment cast with generous risering and controlled pouring — melt is sluggish, gas- and hot-tear-sensitive; allow ~2 % shrinkage and machining stock.
What is the maximum service temperature of GX3Ni36 A+ST?
GX3Ni36 A+ST is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between GX3Ni36-F and GX3Ni36-A?
F is the default condition — standard supply condition for rough castings that will be annealed/stabilised after rough machining. A: softest, most homogeneous condition; lowest and most reproducible expansion coefficient before final machining. Yield strength is 240 MPa in F versus 205 MPa in A.
Sources
- DIN 17745 — Wrought and cast alloys of iron and nickel with defined physical properties — DIN (2002)
- ASM Specialty Handbook: Nickel, Cobalt and Their Alloys (low-expansion Fe-Ni alloys) — ASM International (2000)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Invar 36 / Pernifer 36 alloy datasheets (cast and wrought) — VDM Metals / Aperam / Carpenter (2021)
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.