Steel GX5NiS36
EN 1.3963
GX5NiS36 (1.3963) is a sulfur-bearing cast Invar, a free-machining variant of GX3Ni36 that accepts a small increase in expansion and more scatter in return for much easier machining of cast low-expansion tooling.
Reference datasheet — GX5NiS36 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SR condition
GX5NiS36 tempers and conditions
GX5NiS36 is supplied in 5 conditions, soft to hard. SR is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest and most ductile state; used when maximum machining ease and a homogeneous, low-scatter expansion coefficient are wanted before final stabilizing. | 180 | 400 | 15 | 125 HB | 2.2 % IACS |
SRDefault Stress relieved | Standard delivery condition: removes casting residual stress so parts hold shape through rough and finish machining. | 200 | 420 | 12 | 135 HB | 2.1 % IACS |
Hot isostatic pressed | Optional densification for pressure-tight or fatigue-loaded castings; closes microporosity and raises ductility, at extra cost. | 210 | 450 | 18 | 140 HB | 2.2 % IACS |
As fabricated | Cheapest condition for rough or non-critical low-expansion castings that will be stress-relieved after machining anyway. | 215 | 430 | 10 | 145 HB | 2.1 % IACS |
Dimensionally stabilized | Three-step Invar stabilizing cycle for metrology frames, gauges and optical benches where microstrain drift over years must be minimised. | 220 | 430 | 13 | 140 HB | 2.1 % IACS |
What is GX5NiS36?
GX5NiS36 (1.3963) is a sulfur-bearing cast Invar, a free-machining variant of GX3Ni36 that accepts a small increase in expansion and more scatter in return for much easier machining of cast low-expansion tooling. It is supplied as sand or investment castings in F, SR, A, STAB and HIP conditions with roughly 200 MPa yield, 420 MPa tensile, 12 % elongation, 135 HB, machinability 40 and service to 200 °C. Elongation and weldability are low because of the sulfide inclusions, so use GX3Ni36 where welding or maximum ductility is required. GX5NiS36 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). GX5NiS36 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 98% of steel grades. Elongation at break is 12% and the elastic modulus is 140 GPa (20.3 Msi).
What is GX5NiS36 used for?
- Machined low-expansion tooling castings
- Precision jigs and fixtures
- Measurement standard castings
Advantages
- Good corrosion resistance — 30/100, better than 95% of steel grades
Limitations
- Low stiffness — 140 GPa (20.3 Msi), 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
- 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 strength — 200 MPa (29 ksi), worse than 98% of steel grades
GX5NiS36 properties
Typical room-temperature values for GX5NiS36-SR; bars are the position among steel grades.
Physical3
GX5NiS36 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
GX5NiS36 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 98% of steel grades. Elongation at break is 12% and the elastic modulus is 140 GPa (20.3 Msi).
Thermal6
GX5NiS36 is rated for continuous service to 200°C (392 °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 3 µm/m·K (1.67 µin/in·°F).
Electrical3
GX5NiS36 conducts electricity at 2.1 % IACS, worse than 99% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of GX5NiS36 takes about 110 MJ of energy and emits 8.5 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 35%.
Manufacturability7
GX5NiS36's machinability is fair (40/100, worse than 77% of steel grades); weldability poor (25/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. GX5NiS36 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GX5NiS36
Is GX5NiS36 easy to machine?
Best of the Invar family: run sharp positive-rake carbide at low speed (roughly 25–50 m/min) with heavy flood coolant; the MnS inclusions break chips and reduce the gummy built-up edge typical of Invar 36.
Can GX5NiS36 be welded?
Poor — sulfur strongly promotes solidification cracking; if unavoidable use matched low-S Invar filler, low heat input, preheat-free, and expect a HAZ with degraded expansion behaviour.
Can GX5NiS36 be formed, bent or molded?
A casting alloy only: sand or investment cast with generous risers because of the long freezing range; no meaningful cold formability.
GX5NiS36 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 |
|---|---|---|
| CGX5 designation ≈ 0.05 % C | ≤ 0.07 | 0.05 |
| Si | ≤ 0.6 | 0.3 |
| Mnmust be sufficient to tie up S as MnS | 0.2 – 0.8 | 0.5 |
| P | ≤ 0.03 | 0.02 |
| Sdeliberate free-machining addition | 0.15 – 0.35 | 0.25 |
| Nicontrols the Invar minimum in CTE | 35 – 37 | 36 |
| Coresidual | ≤ 0.5 | |
| Crresidual; raises CTE | ≤ 0.3 | |
| Fe | balance |
What surface finishes work on GX5NiS36?
Not corrosion resistant — protect with oil, paint, electroless Ni or chrome plate; polished surfaces show sulfide pull-out, so lapping needs fine grit and patience.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel GX5NiS36 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.3963
- Also called
- Free-cutting Cast Invar
How much does GX5NiS36 cost?
GX5NiS36 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GX5NiS36 — frequently asked
What is GX5NiS36 used for?
GX5NiS36 is typically used for machined low-expansion tooling castings, precision jigs and fixtures and measurement standard castings. In short: best-machining cast Invar; free-machining Fe-36Ni casting; poor weldability.
What is the yield strength of GX5NiS36?
GX5NiS36 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 98% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is GX5NiS36 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Best of the Invar family: run sharp positive-rake carbide at low speed (roughly 25–50 m/min) with heavy flood coolant; the MnS inclusions break chips and reduce the gummy built-up edge typical of Invar 36.
Can GX5NiS36 be welded?
Not readily — weldability is rated poor (25/100). Poor — sulfur strongly promotes solidification cracking; if unavoidable use matched low-S Invar filler, low heat input, preheat-free, and expect a HAZ with degraded expansion behaviour.
What surface finishes work on GX5NiS36?
Not corrosion resistant — protect with oil, paint, electroless Ni or chrome plate; polished surfaces show sulfide pull-out, so lapping needs fine grit and patience.
Can GX5NiS36 be formed, bent or molded?
A casting alloy only: sand or investment cast with generous risers because of the long freezing range; no meaningful cold formability.
What is the maximum service temperature of GX5NiS36?
GX5NiS36 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 GX5NiS36-SR and GX5NiS36-A?
SR is the default condition — standard delivery condition: removes casting residual stress so parts hold shape through rough and finish machining. A: softest and most ductile state; used when maximum machining ease and a homogeneous, low-scatter expansion coefficient are wanted before final stabilizing. Yield strength is 200 MPa in SR versus 180 MPa in A.
How much does GX5NiS36 cost?
GX5NiS36 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- SEW 385 — Physikalisch bestimmte Eisenlegierungen (Fe-Ni low-expansion cast and wrought alloys) — Verein Deutscher Eisenhüttenleute (VDEh) (1993)
- DIN 17745 — Nickel-Eisen-Knetlegierungen mit vorgeschriebener Wärmeausdehnung — DIN (2002)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Low-Expansion Alloys) — ASM International (1990)
- Cast Invar / free-machining Fe-36Ni foundry alloy data — European low-expansion alloy foundries (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.