ASTM A106 Gr B Spectacle BlindASTM A105 · ASME B16.48 · Manufacturer, stockist & exporter, India
SA-106 Gr B · Seamless carbon steel pipe · SB
An ASTM A106 Gr B spectacle blind is a figure-8 plate with one solid end and one open ring, fitted between two flanges, for use with ASTM A106 Gr B pipe. ASTM A106 Gr B itself is a pipe or plate specification, so the matching spectacle blind is made to ASTM A105 — which is what we supply for A106 B lines. 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 A105
- 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 ASTM A106 Gr B Spectacle Blind?
- What it is
- A figure-8 plate with one solid end and one open ring, fitted between two flanges
- Material
- ASTM A105
- Dimensions
- ASME B16.48
- Grade
- ASTM A106 Gr B
- Best at
- High-temperature process and steam piping in refineries and power plants
ASTM A106 Gr B Spectacle Blind Specification
| Product | ASTM A106 Gr B Spectacle Blind |
|---|---|
| Material standard | ASTM A105 |
| 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 | Chemical & mechanical per heat · NDT · impact where specified |
| 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.
ASTM A106 Gr B Spectacle Blind: Why A106 B 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 ASTM A106 Gr B, 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 | Carbon and low-alloy flanges carry most utility, hydrocarbon and high-temperature service. ASTM A106 Gr B is picked for high-temperature process and steam piping in refineries and power plants. |
|---|---|
| Typical service | Refineries — Process and steam lines. |
| B16.5 material group | 1.1 |
| Bolting | ASTM A193 B7 studs with A194 2H nuts |
| Welding to carbon steel | Matching carbon or low-alloy filler is used; joints to stainless need ER309L |
| Matching filler | ER70S-6 / E7018 |
ASTM A106 Gr B Spectacle Blind Chemical Composition
| Element | Weight % |
|---|---|
| Carbon | 0.30 max |
| Manganese | 0.29 – 1.06 |
| Silicon | 0.10 min |
| Phosphorus | 0.035 max |
| Sulphur | 0.035 max |
| Chromium | 0.40 max |
| Copper | 0.40 max |
| Nickel | 0.40 max |
ASTM A106 Gr B Spectacle Blind Mechanical Properties
| Minimum values (elongation varies with wall) | Value |
|---|---|
| Tensile strength | 415 MPa · 60 ksi |
| Yield strength 0.2% | 240 MPa · 35 ksi |
| Elongation | 30% |
Full chemistry, properties and equivalents are on the ASTM A106 Gr B grade page.
Other ASTM A106 Gr B flanges
ASTM A106 Gr B Spectacle Blinds for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiASTM A106 Gr B 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 ASTM A106 Gr B spectacle blind have?
It depends on class and temperature. ASTM A106 Gr B forgings are in ASME B16.5 material group 1.1; read your class column in that group's table at the design temperature.
Can ASTM A106 Gr B spectacle blinds be welded to carbon steel?
Yes — matching carbon or low-alloy filler is used; joints to stainless need ER309L.
Which standard covers ASTM A106 Gr B spectacle blinds?
The material is ASTM A105; 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 ASTM A106 Gr B spectacle blind?
The steel 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