N-SF11 SF11
Grade
SF11 = classic lead-containing heavy flint
Use the classic lead-containing heavy flint only for legacy designs or when lower thermal expansion and more stable index versus temperature are required; about 50% PbO restricts it under RoHS.
Values for the SF11 condition
Other N-SF11 tempers and conditions
N-SF11 is listed in 3 conditions; see the grade overview at N-SF11.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
N-SF11Default Lead- and arsenic-free heavy flint, standard (coarse) annealed… | Pick the standard coarse-annealed block or strip as the default lead- and arsenic-free high-index flint for achromatic cemented doublets and high-power lenses. | — | 45 | 0 | 470 HV | 0.75 W/m·K |
N-SF11 fine/precision annealed | Choose the slow, precision-annealed material for high-accuracy imaging and interferometric optics: index homogeneity and internal stress birefringence are markedly better than coarse annealed stock. | — | 45 | 0 | 470 HV | 0.75 W/m·K |
SF11This page Classic lead-containing heavy flint | Use the classic lead-containing heavy flint only for legacy designs or when lower thermal expansion and more stable index versus temperature are required; about 50% PbO restricts it under RoHS. | — | — | — | 420 HV | 0.74 W/m·K |
What is N-SF11 SF11?
N-SF11 SF11 is N-SF11 in the SF11 grade — use the classic lead-containing heavy flint only for legacy designs or when lower thermal expansion and more stable index versus temperature are required; about 50% PbO restricts it under RoHS. N-SF11 SF11 has a tensile strength of 45 MPa (6.53 ksi), weaker than 56% of glass grades. Elongation at break is 0% and the elastic modulus is 66 GPa (9.57 Msi). N-SF11 SF11 has a density of 4.74 g/cm³ (0.171 lb/in³), heavier than 85% of glass grades. N-SF11 is the default condition FabDigit quotes; SF11 is available on request or by drawing note.
Limitations
- Poor heat conductor — 0.74 W/m·K (0.428 BTU/hr·ft·°F), worse than 92% of glass grades
- Heavy — 4.74 g/cm³ (0.171 lb/in³), worse than 85% of glass grades
N-SF11 SF11 properties
Typical room-temperature values for N-SF11 SF11; 14 are specific to this condition. Other listed values are N-SF11 reference data and may not represent this condition. Bars are the position among glass grades.
Physical4
N-SF11 SF11 has a density of 4.74 g/cm³ (0.171 lb/in³), heavier than 85% of glass grades.
Mechanical13
N-SF11 SF11 has a tensile strength of 45 MPa (6.53 ksi), weaker than 56% of glass grades. Elongation at break is 0% and the elastic modulus is 66 GPa (9.57 Msi).
Thermal5
N-SF11 SF11 is rated for continuous service to 380°C (716 °F). It conducts heat at 0.74 W/m·K (0.428 BTU/hr·ft·°F), worse than 92% of glass grades. Thermal expansion is 6.1 µm/m·K (3.39 µin/in·°F).
Electrical2
N-SF11 SF11 has an electrical resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 74% of glass grades.
Sustainability4
Producing a kilogram of N-SF11 SF11 takes about 60 MJ of energy and emits 4 kg of CO₂ — more than 58% of glass grades. Typical recycled content is 20%.
Manufacturability2
N-SF11 SF11's machinability is poor (15/100, worse than 54% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with N-SF11 SF11
Is N-SF11 easy to machine?
Not conventionally machinable: shape by diamond-wheel curve generating, precision lapping and pitch or polyurethane polishing. The material is relatively soft and scratches readily, so control abrasive grit size and pressure and support edges to prevent chipping.
Can N-SF11 be welded?
Not weldable; elements are held by optical cement (UV or thermal cure), optical contact, or mechanical mounts. Allow for cement-layer stress caused by CTE mismatch with crown glasses.
Can N-SF11 be formed, bent or molded?
Melted in crucible or continuous furnaces and formed into strip or pressed blanks, then annealed. The low softening point allows precision moulding of aspheres in graphite moulds under inert atmosphere.
What surface finishes work on N-SF11?
AR-coat as soon as possible after polishing: single-surface reflection is about 7%, so an uncoated element loses roughly 14% across both faces. Clean with neutral solvents only and store dry.
N-SF11 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.
| Element | Spec limit (wt %) |
|---|---|
| TiO2main high-index/high-dispersion component, lead-free flint | — |
| Nb2O5raises refractive index and dispersion | — |
| BaOadjusts refractive index and melting behavior | — |
| Na2Oalkali oxide flux | — |
| K2Oalkali oxide flux | — |
| ZrO2improves chemical durability (small addition) | — |
| PbON-SF11 Pb- and As-free; legacy SF11 has about 50 wt% PbO | ≈ 0 |
| SiO2network former, balance; exact formulation proprietary | balance |
N-SF11 SF11 — frequently asked
What is N-SF11 SF11 used for?
N-SF11 SF11 is typically used for achromatic doublets, camera lenses, prisms and optical instruments. In short: high index, high dispersion; lead-free SF11 replacement.
What is the tensile strength of N-SF11 SF11?
N-SF11 SF11 has a typical tensile strength of 45 MPa (6.53 ksi) — weaker than 56% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is N-SF11 SF11 easy to machine?
Not especially — machinability is rated poor (15/100, worse than 54% of glass grades). Not conventionally machinable: shape by diamond-wheel curve generating, precision lapping and pitch or polyurethane polishing. The material is relatively soft and scratches readily, so control abrasive grit size and pressure and support edges to prevent chipping.
Can N-SF11 SF11 be welded?
Not weldable; elements are held by optical cement (UV or thermal cure), optical contact, or mechanical mounts. Allow for cement-layer stress caused by CTE mismatch with crown glasses.
What surface finishes work on N-SF11 SF11?
AR-coat as soon as possible after polishing: single-surface reflection is about 7%, so an uncoated element loses roughly 14% across both faces. Clean with neutral solvents only and store dry.
Can N-SF11 SF11 be formed, bent or molded?
Melted in crucible or continuous furnaces and formed into strip or pressed blanks, then annealed. The low softening point allows precision moulding of aspheres in graphite moulds under inert atmosphere.
What is the maximum service temperature of N-SF11 SF11?
N-SF11 SF11 is rated for continuous use to about 380°C (716 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- N-SF11 Optical Glass Data Sheet — SCHOTT AG (2023)
- Optical Glass Collection Datasheets / TIE technical information — SCHOTT AG (2022)
- ASM Engineered Materials Handbook, Vol.4: Ceramics and Glasses — ASM International (1991)
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.