SS 316 / 316L Spectacle BlindASTM A182 · ASME B16.48 · Manufacturer, stockist & exporter, India
AISI 316L · UNS S31603 · SB
An SS 316 / 316L spectacle blind is a figure-8 plate with one solid end and one open ring, fitted between two flanges, made from SS 316 / 316L to ASTM A182 F316L. A spectacle blind lets operators positively isolate a line: rotate the solid end into the line to block flow, or the ring end to allow it. Larger sizes use separate spacers and paddle blanks.
- ASTM A182
- ASME B16.48
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an SS 316 / 316L Spectacle Blind?
- What it is
- A figure-8 plate with one solid end and one open ring, fitted between two flanges
- Material
- ASTM A182 F316L
- Dimensions
- ASME B16.48
- Grade
- SS 316 / 316L · UNS S31603
- Best at
- Chloride-bearing process fluids, marine air and pharmaceutical service
SS 316 / 316L Spectacle Blind Specification
| Product | SS 316 / 316L Spectacle Blind |
|---|---|
| Material standard | ASTM A182 F316L |
| Dimensional standard | ASME B16.48 |
| Sizes | ½" – 24" (ASME B16.5) · 26" – 60" (ASME B16.47) |
| Pressure class | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | RF · FF · RTJ · tongue & groove |
| Bore | To match pipe schedule (state on order) |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Spectacle Blind
A spectacle blind lets operators positively isolate a line: rotate the solid end into the line to block flow, or the ring end to allow it. Larger sizes use separate spacers and paddle blanks.
- Thickness set by class and size
- Paddle blank and spacer versions for large bores
- Handle or lifting lug to order
More on choosing: Spectacle blind guide.
SS 316 / 316L Spectacle Blind: Why 316L for spectacle blinds
A spectacle blind lets operators positively isolate a line: rotate the solid end into the line to block flow, or the ring end to allow it. Larger sizes use separate spacers and paddle blanks. In SS 316 / 316L, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Stainless flanges are chosen where carbon steel would rust or contaminate the process. SS 316 / 316L is picked for chloride-bearing process fluids, marine air and pharmaceutical service. |
|---|---|
| Typical service | Chemical & process — Piping and vessels handling mild acids and chlorides. |
| B16.5 material group | 2.3 |
| Bolting | ASTM A193 B8M studs with A194 8M nuts |
| Welding to carbon steel | ER309L (or E309L electrode) is the usual filler when joining it to carbon steel |
| Matching filler | ER316L (AWS A5.9) |
SS 316 / 316L Spectacle Blind Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 16.0 – 18.0 |
| Nickel | 10.0 – 14.0 |
| Molybdenum | 2.00 – 3.00 |
| Carbon | 0.030 max |
| Manganese | 2.00 max |
| Silicon | 0.75 max |
| Nitrogen | 0.10 max |
| Phosphorus | 0.045 max |
SS 316 / 316L Spectacle Blind Mechanical Properties
| Annealed plate & sheet (316L) | Value |
|---|---|
| Tensile strength | 485 MPa · 70 ksi |
| Yield strength 0.2% | 170 MPa · 25 ksi |
| Elongation | 40% |
| Hardness | 217 HB max |
Full chemistry, properties and equivalents are on the SS 316 / 316L grade page.
Other SS 316 / 316L flanges
SS 316 / 316L Spectacle Blinds for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 316 / 316L Spectacle Blind — questions buyers ask
When should I use a spacer and paddle blank instead of a spectacle blind?
In large sizes a spectacle blind becomes too heavy and awkward, so ASME B16.48 provides separate paddle blanks and spacers.
What pressure rating does a SS 316 / 316L spectacle blind have?
It depends on class and temperature. SS 316 / 316L forgings are in ASME B16.5 material group 2.3; read your class column in that group's table at the design temperature.
Can SS 316 / 316L spectacle blinds be welded to carbon steel?
Yes — ER309L (or E309L electrode) is the usual filler when joining it to carbon steel.
Which standard covers SS 316 / 316L spectacle blinds?
The material is ASTM A182 F316L; dimensions follow ASME B16.48. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 316 / 316L spectacle blind?
The alloy price, the size and pressure class, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026