Duran
EN ISO 3585
Duran is a borosilicate 3.3 glass to DIN ISO 3585, the standard German-market equivalent of Pyrex 7740, Borofloat 33 and Simax.
Reference datasheet — Duran 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 ANN condition
Duran tempers and conditions
Duran is supplied in 3 conditions, soft to hard. ANN 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 |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard low-stress annealed Duran for laboratory glassware, tubing, sight glasses and flameworked assemblies. | 35 | 0 | 580 HV | 1 W/m·K | |
Thermally toughened | Pick when mechanical strength, impact and pressure resistance matter (viewing panels, boiler/oven sight glass); cannot be cut or drilled after toughening. | 100 | 0 | 580 HV | 1 W/m·K | |
Chemically strengthened | Use for thin sections and complex shapes needing strength without the optical distortion of thermal toughening; shallow compression layer is lost by deep scratching or reheating. | 120 | 0 | 600 HV | 1 W/m·K |
What is Duran?
Duran is a borosilicate 3.3 glass to DIN ISO 3585, the standard German-market equivalent of Pyrex 7740, Borofloat 33 and Simax. It is chosen for low thermal expansion, chemical durability (corrosion resistance 92/100) and optical clarity, and is supplied as tube, rod, sheet and blown or pressed labware in annealed, tempered and chemically strengthened conditions. The limits are brittleness — nominal tensile strength is 35 MPa — a service ceiling near 450 °C, and no conventional machining (machinability 10). Fused silica is the alternative when higher temperature or still lower expansion is required. Duran has a density of 2.23 g/cm³ (0.0806 lb/in³), lighter than 85% of glass grades. Duran has a tensile strength of 35 MPa (5.08 ksi), weaker than 75% of glass grades. Elongation at break is 0% and the elastic modulus is 64 GPa (9.28 Msi).
What is Duran used for?
- Laboratory glassware
- Process piping
- Ampoules
- Sight glasses
Advantages
- Lightweight — 2.23 g/cm³ (0.0806 lb/in³), better than 85% of glass grades
- Low embodied carbon — 1.8 kg CO₂/kg, better than 85% of glass grades
- Good corrosion resistance — 92/100, better than 81% of glass grades
Duran properties
Typical room-temperature values for Duran-ANN; bars are the position among glass grades.
Physical4
Duran has a density of 2.23 g/cm³ (0.0806 lb/in³), lighter than 85% of glass grades.
Mechanical12
Duran has a tensile strength of 35 MPa (5.08 ksi), weaker than 75% of glass grades. Elongation at break is 0% and the elastic modulus is 64 GPa (9.28 Msi).
Thermal5
Duran is rated for continuous service to 450°C (842 °F). It conducts heat at 1.2 W/m·K (0.693 BTU/hr·ft·°F), worse than 58% of glass grades. Thermal expansion is 3.3 µm/m·K (1.83 µin/in·°F).
Electrical5
Duran is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (92/100), better than 81% of glass grades.
Sustainability4
Producing a kilogram of Duran takes about 27 MJ of energy and emits 1.8 kg of CO₂ — less than 84% of glass grades. Typical recycled content is 8%.
Manufacturability2
Duran's machinability is not recommended (10/100, worse than 80% of glass grades).
Common Calculations4
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 glass family
Yield strength against density for every glass grade FabDigit runs. Duran is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Duran
Is Duran easy to machine?
No conventional cutting — score-and-break, diamond core drilling, diamond wheel grinding, abrasive waterjet or laser/CNC glass machining, always followed by edge seaming and annealing.
Can Duran be welded?
Flameworked/fusion-joined with oxy-propane or oxy-hydrogen at ~1200 °C; freely sealable to other 3.3 borosilicates (Pyrex 7740, Borofloat 33, Simax) and to tungsten/Kovar-type graded seals.
Can Duran be formed, bent or molded?
Formed by tube drawing, blowing or press-forming near the working point (~1260 °C); every formed part must be annealed around 560 °C to remove residual stress.
Duran 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 |
|---|---|---|
| B2O3gives low CTE 3.3 | 12 – 13.5 | 13 |
| Na2Oalkali, with K2O total ~4 % | 3 – 4.5 | 3.5 |
| K2O | 0 – 1 | 0.5 |
| Al2O3improves chemical durability | 2 – 2.5 | 2 |
| SiO2network former | ≥ 80 (balance) |
What surface finishes work on Duran?
Fire polishing or acid (HF/H2SO4) polishing for optical clarity; frosting/etching with HF, screen-printed ceramic or PTFE coatings for markings — no plating or anodizing.
Equivalent designations
Standards and trade names that resolve to Duran in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- ISO 3585
How much does Duran cost?
Duran is a premium-cost glass ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Duran — frequently asked
What is Duran used for?
Duran is typically used for laboratory glassware, process piping, ampoules and sight glasses. In short: standard borosilicate 3.3 glass; low thermal expansion; interchangeable with Pyrex 7740.
What is the tensile strength of Duran?
Duran has a typical tensile strength of 35 MPa (5.08 ksi) — weaker than 75% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is Duran easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 80% of glass grades). No conventional cutting — score-and-break, diamond core drilling, diamond wheel grinding, abrasive waterjet or laser/CNC glass machining, always followed by edge seaming and annealing.
Can Duran be welded?
Flameworked/fusion-joined with oxy-propane or oxy-hydrogen at ~1200 °C; freely sealable to other 3.3 borosilicates (Pyrex 7740, Borofloat 33, Simax) and to tungsten/Kovar-type graded seals.
What surface finishes work on Duran?
Fire polishing or acid (HF/H2SO4) polishing for optical clarity; frosting/etching with HF, screen-printed ceramic or PTFE coatings for markings — no plating or anodizing.
Can Duran be formed, bent or molded?
Formed by tube drawing, blowing or press-forming near the working point (~1260 °C); every formed part must be annealed around 560 °C to remove residual stress.
What is the maximum service temperature of Duran?
Duran is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Duran cost?
Duran is a premium-cost glass ($$$), cheaper than about 51% 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
- DIN ISO 3585 — Borosilicate glass 3.3, properties — DIN/ISO (1999)
- DURAN / BOROFLOAT 33 borosilicate glass technical data — SCHOTT AG (2023)
- ASM Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- ISO 695 / ISO 719 / ISO 720 / DIN 12116 chemical durability test classes — ISO / DIN (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.