GOST / ГОСТ 12820-80 Flanges
India’s Leading ASTM A350 LF2 GOST / ГОСТ 12820-80 Lapped Joint Flanges, GOST / ГОСТ 12820-80 Blind Flanges, SS GOST / ГОСТ 12820-80 Flanges, Inconel ГОСТ 33259:2015 12820-80 Flange Manufacturer & Supplier in India.
Kanak Steel & Engg Co. is a known exporting and manufacturing unit of GOST / ГОСТ 33259:2015 / 12820-80 Flanges, which offers top notch resistance to chloride pressure corrosion cracking.
It is a shape of quarter-flip alloy which makes use of a hollow, perforated and pivoting ball to govern float via it. It is open whilst the ball’s hollow is consistent with the float and closed whilst it’s far pivoted 90-tiers through the cope with. The cope with lies flat in alignment with the float whilst open, and is perpendicular to it whilst closed, making for smooth visible affirmation of the status. It has top notch corrosion resistance to an extensive kind of media, with brilliant resistance to pitting and crevice corrosion in seawater and different chloride containing environments.
They are getting used for oil refining, fertilizer, papermaking, petroleum and different fields with excessive request of resistant for sea, excessive temperature like exchanger, condenser’s equipment, etc. It has a number of the top notch functions like having excellent resistance to pressure corrosion cracking, right resistance to fashionable corrosion and pitting. It gives excessive energy about two times the evidence energy of austenitic steels. It offers bodily homes that provide layout advantages, ease of fabrication and right toughness, right weldability, and others. Corrosion resistance of flanges is advanced to different duplex stainless steels due to the fact its alloy content material is higher.
It has an excessive pitting resistance equivalency wide variety for advanced resistance to chloride pitting and pressure corrosion cracking. It combines excessive tensile and effect energy with a low coefficient of thermal growth and excessive thermal conductivity. These flanges are appropriate for lots structural and mechanical components. It gives precise advantages in relation to: Pitting corrosion, Stress corrosion cracking, and Corrosion fatigue cracking. Parallel to the excessive mechanical energy values, they’ve very excessive resistance to abrasive pressure. Meanwhile, the precise benefit of flanges as abrasion resistant steels is the reality that those steels are completely appropriate for welding, that is most effective the case to a restricted quantity with simply abrasion resistant steels.
Largest Manufacturer & Supplier of GOST / ГОСТ 12820-80 Welding Flange, Duplex steel 2205 GOST 12820-80 Ring Type Joint Flanges, GOST / ГОСТ 33259:2015 12820-80 Carbon steel BLRF Flange, GOST / ГОСТ 12820-80 Plate Flange, GOST / ГОСТ 12820-80 - Flange Supplier in Mumbai.
Specification Of GOST / ГОСТ 33259:2015 12820-80 Flanges
Specifications | GOST / ГОСТ 12820-80 Flanges |
---|---|
GOST / ГОСТ 12820-80 Flange size range | 1/2″ (15 NB) to 48″ (1200NB) DN10~DN5000 |
Specialized manufacturer of | DIN 2566 en 1092 1 Pn16 Flange DIN 2566 pn16 Rtj Flange GOST / ГОСТ 12820-80 Sorf Flange GOST / ГОСТ 12820-80 Table Flanges DIN 2566 pn10 GOST / ГОСТ 12820-80 Large Diameter Flange GOST / ГОСТ 12820-80 Threaded Flanges GOST / ГОСТ 12820-80 Blind Flanges GOST / ГОСТ 12820-80 Plate Flanges GOST / ГОСТ 12820-80 Weld Neck Flanges GOST / ГОСТ 12820-80 Loose Flanges GOST / ГОСТ 12820-80 Orifice Flanges GOST / ГОСТ 12820-80 Slip-On Flanges GOST / ГОСТ 12820-80 Lap Joint Flanges GOST / ГОСТ 12820-80 Socketweld FlangesGOST / ГОСТ 12820-80 AS 4087 Water Flanges |
Main Types | Forged / Threaded / Screwed / Plate |
Production technique | Forged, Heat treated and machined |
Special design | As per your drawing
AS, ANSI, BS, DIN and JIS JIS Threaded Flange, Socketweld Flange, Slip-On Flange, Blind Flange, Weld Neck Flange |
Flange supporting material | Gasket, Ring Joint, Flange Bolts |
Test | Hydrostatic testing machine, Direct-reading Spectrograph,UI trasonic flaw detector, X-ray detector, Magnetic particle detector |
Equipment | Bending machine, Press machine, electric bevelling machine, Pushing Machine, Sand-blasting machine etc |
Origin | West Europe /Indian / USA / Japan / Korean |
Key markets and industries for GOST / ГОСТ 12820-80 Flange | Nuclear power (mostly seamless). Heavy oil refineries. Bitumen upgraders. Petrochemicals and acids. |
Export to | Indonesia, Ireland, Ukraine, Singapore,Saudi Arabia,Canada, Peru, Dubai, Brazil, Iran, Korea, USA, India, Egypt, Thailand, Spain, Oman etc |
GOST / ГОСТ 12820-80 Flanges Application | To Connect Pipe & Tubes in Power, Petroleum,Construction, Chemical, Gas, Shipbuilding,Metallurgy, etc |
Material Test Certificates (MTC) as per EN 10204 3.1 and EN 10204 3.2, Test Certificates certifying NACE MR0103, NACE MR0175 |
GOST/ГОСТ 33259:2015/12820-80 Flange PN0.6MPa DIMENSION
Pressure PN = 0,6 MPa (6 kg / s m ²) | |||||||
name | D, мм | D1, мм | dв, мм | b, мм | d, мм | отв., шт. | Масса, кг. |
GOST 12820-80 flat flange (01) 1-15-6 Article 3 (20) | 80 | 55 | 19 | 10 | 11 | 4 | 0,33 |
GOST 12820-80 flat flange (01) 1-20-6 Article 3 (20) | 90 | 65 | 26 | 12 | 0,53 | ||
GOST 12820-80 flat flange (01) 1-25-6 Article 3 (20) | 100 | 75 | 33 | 12 | 0,64 | ||
GOST 12820-80 flat flange (01) 1-32-6 Article 3 (20) | 120 | 90 | 39 | 13 | 14 | 1,01 | |
GOST 12820-80 flat flange (01) 1-40-6 Article 3 (20) | 130 | 100 | 46 | 13 | 1,21 | ||
GOST 12820-80 flat flange (01) 1-50-6 Article 3 (20) | 140 | 110 | 59 | 13 | 1,33 | ||
GOST 12820-80 flat flange (01) 1-65-6 Article 3 (20) | 160 | 130 | 78 | 13 | 1,63 | ||
GOST 12820-80 flat flange (01) 1-80-6 Article 3 (20) | 185 | 150 | 91 | 15 | 18 | 2,44 | |
GOST 12820-80 flat flange (01) 1-100-6 Article 3 (20) | 205 | 170 | 110 | 15 | 2,85 | ||
GOST 12820-80 flat flange (01) 1-125-6 Article 3 (20) | 235 | 200 | 135 | 17 | 8 | 3,88 | |
GOST 12820-80 flat flange (01) 1-150-6 Article 3 (20) | 260 | 225 | 161 | 17 | 4,39 | ||
GOST 12820-80 flat flange (01) 1-200-6 Article 3 (20) | 315 | 280 | 222 | 19 | 5,89 | ||
GOST 12820-80 flat flange (01) 1-250-6 Article 3 (20) | 370 | 335 | 273 | 20 | 12 | 7,67 | |
GOST 12820-80 flat flange (01) 1-300-6 Article 3 (20) | 435 | 395 | 325 | 20 | 22 | 10,28 | |
GOST 12820-80 flat flange (01) 1-350-6 Article 3 (20) | 485 | 445 | 377 | 22 | 12,58 | ||
GOST 12820-80 flat flange (01) 1-400-6 Article 3 (20) | 535 | 495 | 426 | 24 | 16 | 15,2 | |
GOST 12820-80 flat flange (01) 1-500-6 Article 3 (20) | 640 | 600 | 530 | 25 | 19,72 | ||
GOST 12820-80 flat flange (01) 1-600-6 Article 3 (20) | 755 | 705 | 630 | 25 | 26 | 20 | 26,24 |
GOST 12820-80 flat flange (01) 1-800-6 Article 3 (20) | 975 | 920 | 820 | 27 | 30 | 24 | 46,14 |
GOST 12820-80 flat flange (01) 1-1000-6 Article 3 (20) | 1 175 | 1 120 | 1 020 | 31 | 28 | 64,36 | |
GOST 12820-80 flat flange (01) 1-1200-6 Article 3 (20) | 1 400 | 1 340 | 1 220 | 34 | 33 | 32 | 99,03 |
Dimensions of GOST / ГОСТ 12820-80 Plane/Flat Flange (1.6mpa)
Dn, Millimeter | D, Millimeter | D1, Millimeter | dв, Millimeter | b, Millimeter | d, Millimeter | n-¢ | Kilogram |
15 | 95 | 65 | 19 | 12 | 14 | 4 | 0,61 |
20 | 105 | 75 | 26 | 14 | 14 | 4 | 0,86 |
25 | 115 | 85 | 33 | 16 | 14 | 4 | 1,17 |
32 | 135 | 100 | 39 | 16 | 18 | 4 | 1,58 |
40 | 145 | 110 | 46 | 17 | 18 | 4 | 1,96 |
50 | 160 | 125 | 59 | 19 | 18 | 4 | 2,58 |
65 | 180 | 145 | 78 | 21 | 18 | 4 | 3,42 |
80 | 195 | 160 | 91 | 21 | 18 | 4 | 3,71 |
100 | 215 | 180 | 110 | 23 | 18 | 8 | 4,73 |
125 | 245 | 210 | 135 | 25 | 18 | 8 | 6,38 |
150 | 280 | 240 | 161 | 25 | 22 | 8 | 7,81 |
200 | 335 | 295 | 222 | 27 | 22 | 12 | 10,10 |
250 | 405 | 355 | 273 | 28 | 26 | 12 | 14,49 |
300 | 460 | 410 | 325 | 28 | 26 | 12 | 17,78 |
350 | 520 | 470 | 377 | 30 | 26 | 16 | 22,88 |
400 | 580 | 525 | 426 | 34 | 30 | 16 | 31,00 |
500 | 710 | 650 | 530 | 44 | 33 | 20 | 57,01 |
600 | 840 | 770 | 630 | 45 | 39 | 20 | 80,03 |
800 | 1 020 | 950 | 820 | 49 | 39 | 24 | 104,41 |
1000 | 1255 | 1170 | 1 020 | 58 | 45 | 28 | 179,37 |
1200 | 1485 | 1390 | 1220 | 71 | 52 | 32 | 297,78 |
Dimensions of GOST / ГОСТ 12820-80 Welding Neck Flange (1.6mpa)
Dn, Millimeter | D, Millimeter | D1, Millimeter | d, Millimeter | Dm, Millimeter | Dn, Millimeter | d1, Millimeter | b, Millimeter | h4, Millimeter | n-¢ | Kilogram |
15 | 95 | 65 | 14 | 30 | 19 | 12 | 12 | 33 | 4 | 0,68 |
20 | 105 | 75 | 14 | 38 | 26 | 18 | 12 | 36 | 4 | 0,87 |
25 | 115 | 85 | 14 | 45 | 33 | 25 | 12 | 38 | 4 | 1,05 |
32 | 135 | 100 | 18 | 55 | 39 | 31 | 13 | 40 | 4 | 1,54 |
40 | 145 | 110 | 18 | 64 | 46 | 38 | 13 | 42 | 4 | 1,85 |
50 | 160 | 125 | 18 | 76 | 58 | 49 | 13 | 45 | 4 | 2,28 |
65 | 180 | 145 | 18 | 94 | 77 | 66 | 15 | 47 | 4 | 3,19 |
80 | 195 | 160 | 18 | 110 | 90 | 78 | 17 | 50 | 4 | 4,21 |
100 | 215 | 180 | 18 | 130 | 110 | 96 | 17 | 50 | 8 | 4,90 |
125 | 245 | 210 | 18 | 156 | 135 | 121 | 19 | 57 | 8 | 6,75 |
150 | 280 | 240 | 22 | 180 | 161 | 146 | 19 | 57 | 8 | 8,30 |
200 | 335 | 295 | 22 | 240 | 222 | 202 | 21 | 58 | 12 | 11,79 |
250 | 405 | 355 | 26 | 292 | 278 | 254 | 23 | 65 | 12 | 17,36 |
300 | 460 | 410 | 26 | 346 | 330 | 303 | 24 | 66 | 12 | 22,76 |
350 | 520 | 470 | 26 | 400 | 382 | 351 | 28 | 70 | 16 | 32,04 |
400 | 580 | 525 | 30 | 450 | 432 | 398 | 32 | 75 | 16 | 43,00 |
500 | 710 | 650 | 33 | 559 | 535 | 501 | 38 | 90 | 20 | 70,97 |
600 | 840 | 770 | 39 | 660 | 636 | 602 | 41 | 90 | 20 | 99,30 |
800 | 1020 | 950 | 39 | 850 | 826 | 792 | 45 | 95 | 24 | 130,57 |
1 000 | 1255 | 1170 | 45 | 1060 | 1 028 | 992 | 49 | 110 | 28 | 203,39 |
1200 | 1485 | 1390 | 52 | 1268 | 1228 | 1192 | 51 | 125 | 32 | 284,94 |
Dimension of GOST / ГОСТ 12820-80 Blind Flanges (1.6mpa)
Normal Pipe Size | Weight In Kilogram | D | D1 | Number OF Holes | h | D4 | b | D3 | D2 | h1 |
15 | 95 | 65 | 45 | 12 | 10 | 14 | 2 | 2 | 4 | 0.43 |
20 | 105 | 75 | 58 | 12 | 16 | 14 | 2 | 2 | 4 | 0.55 |
25 | 115 | 85 | 68 | 12 | 22 | 14 | 2 | 2 | 4 | 0.67 |
32 | 135 | 100 | 78 | 12 | 28 | 18 | 2 | 2 | 4 | 0.91 |
40 | 145 | 110 | 88 | 14 | 36 | 18 | 3 | 2 | 4 | 1.24 |
50 | 160 | 125 | 102 | 14 | 46 | 18 | 3 | 2 | 4 | 1.55 |
65 | 180 | 145 | 122 | 14 | 60 | 18 | 3 | 2 | 4 | 2.04 |
80 | 195 | 160 | 138 | 14 | 76 | 18 | 3 | 2 | 4 | 2.44 |
100 | 215 | 180 | 158 | 16 | 94 | 18 | 3 | 2 | 8 | 3.51 |
125 | 245 | 210 | 188 | 16 | 118 | 18 | 3 | 2 | 8 | 4.69 |
150 | 280 | 240 | 212 | 18 | 142 | 23 | 3 | 2 | 8 | 6.99 |
200 | 335 | 295 | 268 | 20 | 196 | 23 | 3 | 2 | 12 | 11.49 |
250 | 390 | 355 | 320 | 24 | 244 | 27 | 3 | 2 | 12 | 19.74 |
300 | 405 | 410 | 378 | 28 | 294 | 27 | 4 | 3 | 12 | 29.58 |
350 | 460 | 470 | 438 | 32 | 344 | 27 | 4 | 3 | 16 | 44.22 |
400 | 520 | 525 | 490 | 34 | 390 | 30 | 4 | 3 | 16 | 59.86 |
500 | 580 | 650 | 610 | 40 | 490 | 33 | 4 | 3 | 20 | 102.69 |
600 | 710 | 770 | 720 | 45 | 590 | 40 | 5 | 4 | 20 | 161.98 |
800 | 840 | 950 | 900 | 52 | 780 | 40 | 5 | 4 | 24 | 300.6 |
1000 | 1020 | 1170 | 1110 | 63 | 980 | 46 | 5 | 4 | 28 | 542.16 |
1200 | 1485 | 1390 | 1325 | 75 | 1180 | 52 | 5 | 4 | 32 | 922.18 |
GOST / ГОСТ 12820-80 Flanges Pressure Ratings
Gost 12820 Flange Pressure Pressure | |||||||
---|---|---|---|---|---|---|---|
Temperature (°C) | Class | ||||||
Class 150 | Class 300 | Class 400 | Class 600 | Class 900 | Class 1500 | Class 2500 | |
-29 – 38 | 19.8 | 51.7 | 68.9 | 103.4 | 155 | 259 | 431 |
50 | 19.5 | 51.7 | 68.9 | 103.4 | 155 | 259 | 431 |
100 | 17.7 | 51.5 | 68.7 | 103.0 | 155 | 258 | 429 |
150 | 15.8 | 50.2 | 66.8 | 100.3 | 151 | 251 | 418 |
200 | 13.8 | 48.6 | 64.8 | 97.2 | 146 | 243 | 405 |
250 | 12.1 | 46.3 | 61.7 | 92.7 | 139 | 232 | 386 |
300 | 10.2 | 42.9 | 57.0 | 85.7 | 129 | 214 | 357 |
325 | 9.3 | 41.4 | 55.0 | 82.6 | 124 | 207 | 344 |
350 | 8.4 | 40.0 | 53.4 | 80.0 | 120 | 200 | 334 |
375 | 7.4 | 37.8 | 50.4 | 75.7 | 114 | 189 | 315 |
400 | 6.5 | 34.7 | 46.3 | 69.4 | 104 | 174 | 290 |
425 | 5.5 | 28.8 | 38.4 | 57.5 | 86.3 | 144 | 240 |
450 | 4.6 | 23.0 | 30.7 | 46.0 | 69.0 | 115 | 192 |
475 | 3.7 | 17.1 | 22.8 | 34.2 | 51.3 | 85.4 | 142 |
500 | 2.8 | 11.6 | 15.4 | 23.2 | 34.7 | 57.9 | 96.5 |
538 | 1.4 | 5.9 | 7.9 | 11.8 | 17.7 | 29.5 | 49.2 |
GOST / ГОСТ 12820-80 Flanges Weight Chart
Standard | Class | Diameter | Bolt Circle Diameter | Number of Bolts | Bolt Size | Diameter of Bolt Hole |
---|---|---|---|---|---|---|
AS4087 Flanges | PN14 | 95 | 67 | 4 | M12 | 14 |
AS 2129 Flange | Table C | 95 | 67 | 4 | 13 | 14 |
Table D | 95 | 67 | 4 | 13 | 14 | |
Table E | 95 | 67 | 4 | 13 | 14 | |
Table F | 95 | 67 | 4 | 13 | 14 | |
Table H | 114 | 83 | 4 | 16 | 17 | |
Table J | 114 | 83 | 4 | 16 | 17 | |
ANSI B16.5 Flanges | ANSI 150 | 89 | 60 | 4 | 13 | 16 |
ANSI 300 | 95 | 67 | 4 | 13 | 16 | |
ANSI 600 | 95 | 67 | 4 | 13 | 16 | |
ANSI 900 | 121 | 83 | 4 | 19 | 22 | |
ANSI 1500 | 121 | 83 | 4 | 19 | 22 | |
ISO 7005 (DIN) Flange | PN6 | 80 | 55 | 4 | M10 | 11 |
PN10 | 95 | 65 | 4 | M12 | 14 | |
PN16 | 95 | 65 | 4 | M12 | 14 | |
PN20 | 90 | 60.5 | 4 | M14 | 16 | |
PN25 | 95 | 65 | 4 | M12 | 14 | |
PN40 | 95 | 65 | 4 | M12 | 14 |
GOST / ГОСТ 12820-80 Flanges Material
Carbon Steel GOST / ГОСТ 12820-80 Flanges | ASTM/ASME A/SA105 A/SA105N & A/SA216-WCB, DIN 1.0402, DIN 1.0460, DIN 1.0619, Die Steel, ASTM A105 / ASME SA105, A105N, ASTM A350 LF2 / ASME SA350, High Yield CS ASTM A694 / A694 (F52 F56 F60 F65 F70 F80) |
Stainless Steel GOST / ГОСТ 12820-80 Flanges | ASTM/ASME A/SA182 F304, F304L, F316, F316L, ASTM/ASME A/SA351 CF8, CF3, CF8M, CF3M, DIN 1.4301, DIN 1.4306, DIN 1.4401, DIN 1.4404, DIN 1.4308, DIN 1.4408, DIN 1.4306, DIN 1.4409 |
Alloy Steel GOST / ГОСТ 12820-80 Flanges | ASTM A182 / ASME SA182 F5, F9, F11, F12, F22, F91 |
Titanium GOST / ГОСТ 12820-80 Flanges | ASTM B381 / ASME SB381, Titanium Gr. 1, Titanium Gr. 2, Titanium Gr. 4, Titanium Gr. 5, Titanium Gr. 7 ASTM R50250/GR.1 | R50400/GR.2 | R50550/GR.3 | R50700/GR.4 | GR.6 |R52400/GR.7 | R53400/GR.12 | R56320/GR.9 |R56400/GR.5 |
Copper GOST / ГОСТ 12820-80 Flanges | T1, T2, C10100, C10200, C10300, C10400, C10500, C10700, C10800, C10910,C10920, TP1, TP2, C10930, C11000, C11300, C11400, C11500, C11600, C12000,C12200, C12300, TU1, TU2, C12500, C14200, C14420, C14500, C14510, C14520, C14530, C17200, C19200, C21000, C23000, C26000, C27000, C27400, C28000, C33000, C33200, C37000, C44300, C44400, C44500, C60800, C63020, C68700, C70400, C70600, C70620, C71000, C71500, C71520, C71640, etc |
Copper Nickel GOST / ГОСТ 12820-80 Flanges | ASTM / ASME SB 61 / 62 / 151 / 152, Copper Nickel 90/10 (C70600 ), Cupro Nickel 70/30 (C71500), UNS C71640 |
Brass GOST / ГОСТ 12820-80 Flanges | 3602 / 2604 / H59 / H62 / etc. |
Inconel GOST / ГОСТ 12820-80 Flanges | ASTM B564 / ASME SB564, Inconel 600, 601, 625, 718, 783, 690, x750 GOST / ГОСТ 12820-80 Flanges |
Hastelloy GOST / ГОСТ 12820-80 Flanges | ASTM B564 / ASME SB564, Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X Flanges |
Monel GOST / ГОСТ 12820-80 Flanges | ASTM B564 / ASME SB564, Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500) |
Alloy 20 GOST / ГОСТ 12820-80 Flanges | ASTM B462 / ASME SB462, Carpenter® 20 Alloy, Alloy 20Cb-3 |
Aluminium GOST / ГОСТ 12820-80 Flanges | 5052 /6061/ 6063 / 2017 / 7075 / etc. |
Nickel GOST / ГОСТ 12820-80 Flanges | ASTM B564 / ASME SB564, Nickel 200, Nickel 201, Nickel 205, Nickel 205LC |
Duplex GOST / ГОСТ 12820-80 Flanges | S31803 / S32205 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61 |
Super Duplex GOST / ГОСТ 12820-80 Flanges | S32750 / S32760 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61 |
Incoloy GOST / ГОСТ 12820-80 Flanges | ASTM B564 / ASME SB564, Incoloy 800, 800H, 800HT (UNS N08800), 825 (UNS N08825), 925 Flanges |
254 Smo GOST / ГОСТ 12820-80 Flanges | ASTM A182 / ASME SA182, SMO 254/6Mo, UNS S31254, DIN 1.4547 |
Nimonic GOST / ГОСТ 12820-80 Flanges | Nimonic 75, Nimonic 80A, Nimonic 90 |
Other GOST / ГОСТ 12820-80 Flanges material | Tin bronze, Alumunum bronze, Lead bronze |
Types of GOST / ГОСТ 12820-80 Flanges We Supply
904L Stainless Steel GOST / ГОСТ 12820-80 Weld Neck Flanges | Cupro Nickel 90-10 GOST / ГОСТ 12820-80 Flanges Facing Type & Finish |
UNS C70600 GOST / ГОСТ 12820-80 SORF Flanges | SS GOST / ГОСТ 12820-80 Groove & Tongue Flanges |
ASTM A105 CS GOST / ГОСТ 12820-80 SWRF Flanges Supplier | Alloy Steel F5 GOST / ГОСТ 12820-80 Square Flanges |
Stainless Steel GOST / ГОСТ 12820-80 Threaded Flanges | GOST / ГОСТ 12820-80 Flanges Supplier |
Stainless Steel 317 GOST / ГОСТ 12820-80 BLFF Flange | Industrial GOST / ГОСТ 12820-80 Flanges Manufacturer |
Monel 400 GOST / ГОСТ 12820-80 Flanges | UNS K41545 GOST / ГОСТ 12820-80 Weld Neck Flanges Series A or B |