What is the maximum thickness of the flange face for ASTM A350 LF2 Blind Flanges?
These flanges use general carbon steel with average strength and impact resistance. An ASTM A350 LF2 blind flange works in cold-temperature service with minimal exposure to corrosive agents. This specification prescribes sizes of ½” to 48” or 60” for wall thicknesses in classes 150, 400, etc., up to 2500 lbs.
Manufacturers can perform customer-specific customisations on an SA 350 Gr LF2 blind flange with normalisation, tempering, and quenching.
What is the difference between an ASTM A350 LF2 Class 1 and Class 2 BLRF Flange?
Both classes have the same chemical composition. The mechanical properties of a Class 1 A350 LF2 BLRF flange and Class 2 are also identical.
The prime difference is the minimum applicable temperature, which is also valid for the Charpy V-notch impact test. An ASTM A350 LF2 Class 1 flat face blind flange has a min. applicable temperature of -50°F or -46°C. But for Class 2, it stands at -0°F or -18°C.
How do you prevent A350 LF2 BLRF Flange face corrosion?
This flange material has moderate corrosion resistance, which can get boosted by a protective coating. For instance, an ASTM A350 LF2 Cl1 blind weld flange can undergo anti-rust painting or galvanisation (zinc coating).
Another way to prevent corrosion is to choose high-quality and application-appropriate components with thorough testing. A 350 LF2 high hub blind flanges need routine maintenance to clean debris and damage.
Type | Material | Sizes |
---|---|---|
Blind | ASTM A350 LF2 |
|
Pressure Rating | Classes | Impact Test Temperature |
Class 150 to Class 2500 | Class 1 and Class 2 | -20 ℉ |
Test Certificates | ASME/ANSI | Face Types |
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ASTM A350 Gr LF2 blind Flange
ASTM A350 LF2 Class 1 blind Flange
SA350 Gr LF2 Cl1 blind flange
ASTM A350 LF2 blind flanges
A350 LF2 blind flange
SA 350 LF2 blind Flange
NPS |
Outside Diameter |
Bolt Circle (BC) | Raised Face (R) | Raised Face (RF) | Raised Face Thickness (T) |
Flat Face Thickness (T2) |
Bolt Hole (B) | No. of Bolt Holes |
---|---|---|---|---|---|---|---|---|
1/2″ | 3.50″ | 2.38″ | 1.38″ | .063″ | .44″ | .38″ | .62″ | 4 |
3/4″ | 3.88″ | 2.75″ | 1.69″ | .063″ | .50″ | .44″ | .62″ | 4 |
1″ | 4.25″ | 3.12″ | 2.00″ | .063″ | .56″ | .50″ | .62″ | 4 |
1-1/4″ | 4.62″ | 3.50″ | 2.50″ | .063″ | .62″ | .56″ | .62″ | 4 |
1-1/2″ | 5.00″ | 3.88″ | 2.88″ | .063″ | .68″ | .62″ | .62″ | 4 |
2″ | 6.00″ | 4.75″ | 3.62″ | .063″ | .75″ | .69″ | .75″ | 4 |
2-1/2″ | 7.00″ | 5.50″ | 4.12″ | .063″ | .88″ | .82″ | .75″ | 4 |
3″ | 7.50″ | 6.00″ | 5.00″ | .063″ | .94″ | .88″ | .75″ | 4 |
3-1/2″ | 8.50″ | 7.00″ | 5.50″ | .063″ | .94″ | .88″ | .75″ | 8 |
4″ | 9.00″ | 7.50″ | 6.19″ | .063″ | .94″ | .88″ | .75″ | 8 |
5″ | 10.00″ | 8.50″ | 7.31″ | .063″ | .94″ | .88″ | .88″ | 8 |
6″ | 11.00″ | 9.50″ | 8.50″ | .063″ | 1.00″ | .94″ | .88″ | 8 |
8″ | 13.50″ | 11.75″ | 10.62″ | .063″ | 1.12″ | 1.06″ | .88″ | 8 |
10″ | 16.00″ | 14.25″ | 12.75″ | .063″ | 1.19″ | 1.13″ | 1.00″ | 12 |
12″ | 19.00″ | 17.00″ | 15.00″ | .063″ | 1.25″ | 1.19″ | 1.00″ | 12 |
14″ | 21.00″ | 18.75″ | 16.25″ | .063″ | 1.38″ | 1.32″ | 1.12″ | 12 |
16″ | 23.50″ | 21.25″ | 18.50″ | .063″ | 1.44″ | 1.38″ | 1.12″ | 16 |
18″ | 25.00″ | 22.75″ | 21.00″ | .063″ | 1.56″ | 1.50″ | 1.25″ | 16 |
20″ | 27.50″ | 25.00″ | 23.00″ | .063″ | 1.69″ | 1.63″ | 1.25″ | 20 |
22″ | 29.50″ | 27.25″ | 25.25″ | .063″ | 1.81″ | 1.75″ | 1.38″ | 20 |
24″ | 32.00″ | 29.50″ | 27.25″ | .063″ | 1.88″ | 1.82″ | 1.38″ | 20 |
Element | Composition, w.t % |
LF2 | Grades |
C | ≤0.30 |
Mn | 0.60-1.35 |
P | ≤0.035 |
S | ≤0.040 |
Si | 0.15-0.30 |
Ni | ≤0.40 |
Cr | ≤0.30 |
Mo | ≤0.12 |
Cu | ≤0.40 |
Cb | ≤0.02 |
V | ≤0.08 |
N | ... |
Grade/Class | Tensile Strength | Yield Strength, min. | Elongation, min. | Hardness, max. | ||
ksi | MPa | ksi | MPa | % | HBW | |
LF2 CL2 | 70–95 | 485–655 | 36 | 250 | 22 | 197 |
NPS | BLRF |
---|---|
½ | 2 |
¾ | 2 |
1 | 2 |
1¼ | 3 |
1½ | 4 |
2 | 5 |
2½ | 7 |
3 | 9 |
3½ | 13 |
4 | 17 |
5 | 20 |
6 | 27 |
8 | 47 |
10 | 70 |
12 | 123 |
14 | 140 |
16 | 180 |
18 | 220 |
20 | 285 |
22 | 355 |
24 | 430 |
NOM PIPE SIZE | DIAMETER OF BOLTS | DIAMETER OF BOLT CIRCLE | LENGTH OF STUDS 1/16" RAISED FACE | # OF BOLTS | BOLT LENGTH |
---|---|---|---|---|---|
0.5 | 0.5 | 2.375 | 2.25 | 4 | 1.75 |
0.75 | 0.5 | 2.75 | 2.25 | 4 | 2 |
1 | 0.5 | 3.125 | 2.5 | 4 | 2 |
1.25 | 0.5 | 3.5 | 2.5 | 4 | 2.25 |
1.5 | 0.5 | 3.875 | 2.75 | 4 | 2.25 |
2 | 0.625 | 4.75 | 3 | 4 | 2.75 |
2.5 | 0.625 | 5.5 | 3.25 | 4 | 3 |
3 | 0.625 | 6 | 3.5 | 4 | 3 |
3.5 | 0.625 | 7 | 3.5 | 8 | 3 |
4 | 0.625 | 7.5 | 3.5 | 8 | 3 |
5 | 0.75 | 8.5 | 3.75 | 8 | 3.25 |
6 | 0.75 | 9.5 | 3.75 | 8 | 3.25 |
8 | 0.75 | 11.75 | 4 | 8 | 3.5 |
10 | 0.875 | 14.25 | 4.5 | 12 | 3.75 |
12 | 0.875 | 17 | 4.5 | 12 | 4 |
14 | 1 | 18.75 | 5 | 12 | 4.25 |
16 | 1 | 21.25 | 5.25 | 16 | 4.5 |
18 | 1.125 | 22.75 | 5.75 | 16 | 4.75 |
20 | 1.125 | 25 | 6 | 20 | 5.25 |
22 | 1.25 | 27.25 | 6.5 | 20 | 5.5 |
24 | 1.25 | 29.5 | 6.75 | 20 | 5.75 |
26 | 1.25 | 31.75 | 7 | 24 | 6 |
30 | 1.25 | 36 | 7.25 | 28 | 6.25 |
34 | 1.5 | 40.5 | 8 | 32 | 7 |
36 | 1.5 | 42.75 | 8.25 | 32 | 7 |
42 | 1.5 | 49.5 | 8.75 | 36 | 7.5 |
Spec | Class | Available Size Range |
B16.5 | 150 | 0.5” – 24” |
B16.5 | 300 | 0.5” – 24” |
B16.47 | 150 | 26” – 60” |
B16.47 | 300 | 26” – 60” |
HSN code | 73072100 |
What are the 6 applications of an SA 350 LF2 Blind Flange?
An SA 350 LF2 blind flange can handle higher pressures but operates at low temperatures. They connect and seal off pipe ends in these sectors:
What are the 8 drawbacks of an A350 Gr LF2 Reducing Blind Flange?
These flanges have a different-sized connection compared to the pipe bore. An A350 Gr LF2 reducing blind flange connects larger and smaller pipes, sealing off one end. It eliminates the need for a reducer.
We recommend being wary of these potential drawbacks:
How do I choose ASTM A350 Gr LF2 Blind Flange thickness?
Manufacturers produce an ASTM A350 Gr LF2 blind flange in various thicknesses. It depends on the pressure exerted and the diameter of the piping.
When choosing the desired dimensions, customers should assess the allowable stress in N/mm2, the corrosion allowance in mm, and the internal diameter of the gasket, if used.
Frequently asked questions:
What is the hardness of an A350 LF2 Cl1 Blind Flange?
The maximum hardness of an A350 LF2 Cl1 blind flange is 197 HB. It conforms to the NACE MR0175 requirements for crude oil sectors.
What is the yield strength of an SA 350 LF2 Class 1 Blind Flange?
An SA 350 LF2 class 1 blind flange has a yield strength of 240 to 250Mpa or 36KSi.
What is the low temp for an A350 LF2 Class 2 BLRF Flange?
The low temperature of ASTM A350 LF2 flanges from Class 2 is above −29°C or −20°F.