Steel K93500
UNS K93500
An Fe-36Ni Invar-family alloy grade (ASTM F1684) with impurity control tailored for glass/metal sealing and low-expansion structural uses, closely related to standard Invar 36 (K93600) but a distinct UNS composition class.
Reference datasheet — K93500 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 A condition
K93500 tempers and conditions
K93500 is supplied in 3 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked condition: lowest and most stable CTE, best formability and weldability — use for precision structures, LNG membrane, glass sealing and deep-drawn parts. | 280 | 490 | 40 | 140 HB | 2.1 % IACS |
Temper B | Pick when higher yield strength and better chip control are needed and a small CTE shift / later stress-relief is acceptable — springs' blanks, machined precision bodies, stiffer strip. | 520 | 640 | 15 | 18 HRC | 2.1 % IACS |
Temper C | Maximum strength/hardness strip and wire for spring-like or wear-loaded low-expansion parts; ductility, weldability and CTE stability are the trade-offs. | 740 | 830 | 4 | 27 HRC | 2.1 % IACS |
What is K93500?
An Fe-36Ni Invar-family alloy grade (ASTM F1684) with impurity control tailored for glass/metal sealing and low-expansion structural uses, closely related to standard Invar 36 (K93600) but a distinct UNS composition class. K93500 has a density of 8.05 g/cm³ (0.291 lb/in³), heavier than 96% of steel grades. It melts at 1,427°C (2,601 °F). K93500 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 90% of steel grades. Elongation at break is 40% and the elastic modulus is 141 GPa (20.5 Msi).
What is K93500 used for?
- Glass-to-metal seal components
- Precision measuring devices
- Bimetal strip cores
- Thermostat components
Advantages
- Ductile — tolerates forming and impact — 40%, better than 99% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- Good corrosion resistance — 22/100, better than 90% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Poor heat conductor — 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 100% of steel grades
- Low electrical conductivity — 2.1 % IACS, worse than 99% of steel grades
- High embodied carbon — 7.5 kg CO₂/kg, worse than 99% of steel grades
- Low stiffness — 141 GPa (20.5 Msi), worse than 98% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
K93500 properties
Typical room-temperature values for K93500-A; bars are the position among steel grades.
Physical3
K93500 has a density of 8.05 g/cm³ (0.291 lb/in³), heavier than 96% of steel grades. It melts at 1,427°C (2,601 °F).
Mechanical15
K93500 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 90% of steel grades. Elongation at break is 40% and the elastic modulus is 141 GPa (20.5 Msi).
Thermal6
K93500 is rated for continuous service to 200°C (392 °F). It conducts heat at 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 100% of steel grades. Thermal expansion is 1.3 µm/m·K (0.722 µin/in·°F).
Electrical3
K93500 conducts electricity at 2.1 % IACS, worse than 99% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of K93500 takes about 100 MJ of energy and emits 7.5 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 30%.
Manufacturability8
K93500's machinability is poor (30/100, worse than 89% of steel grades); weldability very good (70/100); formability excellent (85/100).
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. K93500 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with K93500
Is K93500 easy to machine?
Gummy and work-hardening — use sharp positive-rake carbide, rigid setups, heavy positive feed, low-to-moderate speed (25–45 m/min) and flood coolant; avoid dwelling to prevent glazing.
Can K93500 be welded?
GTAW, EBW and laser welding with matching Fe-36Ni filler and low heat input work well; keep sulphur/carbon pickup out of the joint and re-anneal to restore low, uniform CTE.
Can K93500 be formed, bent or molded?
Annealed sheet deep-draws and spins readily but hardens fast — plan interstage anneals at 800–900 °C and a final stress-relief/stabilisation cycle (e.g. 830 °C anneal + 315 °C stabilise) for dimensional parts.
K93500 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 |
|---|---|---|
| NiInvar composition window; exact Ni sets the CTE minimum | 35 – 37 | 36 |
| Clow C for dimensional stability | ≤ 0.1 | 0.03 |
| Mn | ≤ 0.6 | 0.35 |
| Si | ≤ 0.3 | 0.15 |
| P | ≤ 0.03 | |
| Skept low for glass sealing and weldability | ≤ 0.03 | |
| Crresidual | ≤ 0.25 | |
| Coresidual; higher Co gives Super-Invar/Kovar classes | ≤ 0.5 | |
| Alresidual deoxidiser | ≤ 0.1 | |
| Fe | balance |
What surface finishes work on K93500?
Not anodizable; protect with electroless nickel, chromium, gold or tin plating, black oxide or oil — bare surfaces rust quickly in humid air and can contaminate optics.
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 K93500 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Invar
- Similar grades
- F16844J36
How much does K93500 cost?
K93500 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.
K93500 — frequently asked
What is K93500 used for?
K93500 is typically used for glass-to-metal seal components, precision measuring devices, bimetal strip cores and thermostat components. In short: sealing-grade Invar composition; near-zero ambient expansion; poor machinability, needs plating.
What is the yield strength of K93500?
K93500 has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 90% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is K93500 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Gummy and work-hardening — use sharp positive-rake carbide, rigid setups, heavy positive feed, low-to-moderate speed (25–45 m/min) and flood coolant; avoid dwelling to prevent glazing.
Can K93500 be welded?
Yes — weldability is rated very good (70/100). GTAW, EBW and laser welding with matching Fe-36Ni filler and low heat input work well; keep sulphur/carbon pickup out of the joint and re-anneal to restore low, uniform CTE.
What surface finishes work on K93500?
Not anodizable; protect with electroless nickel, chromium, gold or tin plating, black oxide or oil — bare surfaces rust quickly in humid air and can contaminate optics.
Can K93500 be formed, bent or molded?
Annealed sheet deep-draws and spins readily but hardens fast — plan interstage anneals at 800–900 °C and a final stress-relief/stabilisation cycle (e.g. 830 °C anneal + 315 °C stabilise) for dimensional parts.
What is the maximum service temperature of K93500?
K93500 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 K93500-A and K93500-C?
A is the default condition — standard stocked condition: lowest and most stable CTE, best formability and weldability — use for precision structures, LNG membrane, glass sealing and deep-drawn parts. C: maximum strength/hardness strip and wire for spring-like or wear-loaded low-expansion parts; ductility, weldability and CTE stability are the trade-offs. Yield strength is 280 MPa in A versus 740 MPa in C.
How much does K93500 cost?
K93500 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
- ASTM F1684 – Standard Specification for Iron-Nickel and Iron-Nickel-Cobalt Alloys for Low Thermal Expansion Applications — ASTM International (2022)
- GB/T 15018 / YB/T 5241 4J36 (2018)
- ASM Specialty Handbook: Nickel, Cobalt and Their Alloys / ASM Handbook Vol.2 — ASM International (2000)
- Invar 36 alloy technical datasheet — Carpenter Technology / Aperam-Imphy (2021)
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.