GOST 12820-80 Steel Plate Flanges Flat flange for pipes

Manufacturer of GOST 12820-80 Flat flange for pipes

We are a trusted manufacturer and global supplier of GOST 12820-80 flanges, designed in accordance with the Russian standard for flat welded steel flanges. These flanges are widely used in pipeline systems for oil, gas, chemical, power, and industrial plants across CIS countries and international markets.

GOST 12820-80 steel plate flanges are flat flanges for pipes (slip-on type) manufactured in accordance with the Russian standard GOST 12820-80. These flanges are widely used in oil & gas, petrochemical, power generation, water supply, and industrial piping systems, especially in projects following GOST or Russian standards.

What is GOST 12820-80 Flat Flange?

GOST 12820-80 is a Russian standard that specifies flat welding flanges (also known as flat plate flanges) used for pipelines, valves, and pressure vessels. These flanges are typically welded to the end of a pipe and used in low- and medium-pressure systems. The sealing face is flat, making it ideal for connections that use a flat gasket between two flanges.

These flanges are typically welded directly to pipes and are designed to handle working pressures up to 2.5 MPa (25 kgf/cm²).

⬇️ Download GOST 12820-80 standard Now (PDF)

1. This standard applies to steel flat welded flanges for pipelines and connecting parts, as well as to connecting flanges for fittings, connecting parts of machines, devices, nozzles of apparatuses and reservoirs, with a nominal pressure Py​ from 0.1 to 2.5 MPa (from 1 to 25 kgf/cm²) and a medium temperature from 203 to 573 K (from minus 70 to plus 300 °C). The requirements of paragraphs 1; 2 (excluding the “Mass” indicator); 3; 6; 10; 11 of this standard are mandatory, and the remaining requirements are recommendatory. (Revised edition, Rev. No. 4).

GOST 12820-80 Flat flange specification

Type: Flat welding flange (плоский приварной фланец) — also called a slip-on flange in international terminology

Connection method: Welded directly to the pipe (typically with a fillet weld)

Pressure ratings:

• PN 0.6 MPa to 2.5 MPa (6 to 25 kgf/cm²)
• Typically for low- to medium-pressure systems

Nominal diameters (DN):

• Ranges from DN 10 to DN 1600 (and sometimes larger)

Sealing surface types:

• Smooth (plain face)
• Raised face (type “B”)
• Grooved face (for gaskets)

Material for GOST-12820-80 flange

• Common carbon steel grades (e.g., Сt20, 09Г2С)
• Stainless steel:12Х18Н10Т; 10Х17Н13М2Т,ASTM A182 F304L, F316/316L, F316H, F310, F321 F44
• Alloy steel:ASTM A182 F1, F5a, F9, F11, F12, F22, F91,15Х5М

Dimension of GOST 12820-80 Flat flange

⬇️ Download GOST 12820-80 Flat Weld flange Dimension and Weight (PDF)

Dimension of GOST 12820-80 PN6 Flat flange

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	d1 (mm)	b (mm)	h (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-6	75	50	35	15	10	2	4	11	0.31
1 – 15 – 6	80	55	40	19	10	2	4	11	0.33
1 – 20 – 6	90	65	50	26	12	2	4	11	0.53
1 – 25 – 6	100	75	60	33	12	2	4	11	0.64
1 – 32 – 6	120	90	70	39	13	2	4	14	1.01
1 – 40 – 6	130	100	80	46	13	3	4	14	1.21
1 – 50 – 6	140	110	90	59	13	3	4	14	1.33
1 – 65 – 6	160	130	110	78	13	3	4	14	1.63
1 – 80 – 6	185	150	128	91	15	3	4	18	2.44
1 – 100 – 6	205	170	148	110	15	3	4	18	2.85
1 – 125 – 6	235	200	178	135	17	3	8	18	3.88
1 – 150 – 6	260	225	202	161	17	3	8	18	4.39
1 – 175 – 6	290	255	232	196	19	3	8	18	5.36
1 – 200 – 6	315	280	258	222	19	3	8	18	5.89
1 – 225 – 6	340	305	282	245	19	3	8	18	6.6
1 – 250 – 6	370	335	312	273	20	3	12	18	7.67
1 – 300 – 6	435	395	365	325	20	4	12	22	10.28
1 – 350 – 6	485	445	415	377	22	4	12	22	12.58
1 – 400 – 6	535	495	465	426	24	4	16	22	15.2
1 – 450 – 6	590	550	520	480	24	4	16	22	17.25
1 – 500 – 6	640	600	570	530	25	4	16	22	19.72
1 – 600 – 6	755	705	670	630	25	5	20	26	26.24
1 – 700 – 6	860	810	775	720	27	5	24	26	36.68
1 – 800 – 6	975	920	880	820	27	5	24	30	46.14
1 – 900 – 6	1075	1020	980	920	29	5	24	30	55.1
1 – 1000 – 6	1175	1120	1080	1020	31	5	28	30	64.36
1 – 1200 – 6	1400	1340	1295	1220	34	5	32	33	99.03

Dimension of GOST 12820-80 PN10 Flat flange

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	d1 (mm)	b (mm)	h (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-15-10	90	60	42	15	10	2	4	14	0.46
1 – 15 – 10	95	65	47	19	10	2	4	14	0.51
1 – 20 – 10	105	75	58	26	12	2	4	14	0.74
1 – 25 – 10	115	85	68	33	12	2	4	14	0.89
1 – 32 – 10	135	100	78	39	14	2	4	18	1.4
1 – 40 – 10	145	110	88	46	15	3	4	18	1.71
1 – 50 – 10	160	125	102	59	15	3	4	18	2.06
1 – 65 – 10	180	145	122	78	17	3	4	18	2.8
1 – 80 – 10	195	160	133	91	17	3	4	18	3.19
1 – 100 – 10	215	180	158	110	19	3	8	18	3.96
1 – 125 – 10	245	210	184	135	21	3	8	18	5.4
1 – 150 – 10	280	240	212	161	21	3	8	22	6.62
1 – 175 – 10	310	270	242	196	21	3	8	22	7.32
1 – 200 – 10	335	295	268	222	21	3	8	22	8.05
1 – 225 – 10	365	325	295	245	21	3	8	22	9.3
1 – 250 – 10	390	350	320	273	23	3	12	22	10.65
1 – 300 – 10	440	400	370	325	24	4	12	22	12.9
1 – 350 – 10	500	460	430	377	24	4	16	22	15.85
1 – 400 – 10	565	515	482	426	26	4	16	26	21.56
1 – 450 – 10	615	565	532	480	26	4	20	26	22.76
1 – 500 – 10	670	620	585	530	28	4	20	26	27.7
1 – 600 – 10	780	725	685	630	31	5	20	30	39.4
1 – 700 – 10	895	840	800	720	34	5	24	30	59.46
1 – 800 – 10	1010	950	905	820	37	5	24	33	79.16
1 – 900 – 10	1110	1050	1005	920	40	5	28	33	94.13
1 – 1000 – 10	1220	1160	1110	1020	43	5	28	33	118.4
1 – 1200 – 10	1455	1380	1330	1222	51	5	32	39	197.4
1 – 1400 – 10	1675	1590	1530	1420	60	5	36	45	278.9

Dimension of GOST 12820-80 PN16 Flat flange

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	d1 (mm)	b (mm)	h (mm)	Number of holes (n)	d (mm)	Weight, Kg
1 – 15 – 10	90	60	42	15	12	2	4	14	0.54
1 – 15 – 16	95	65	47	19	12	2	4	14	0.61
1 – 20 – 16	105	75	58	26	14	2	4	14	0.86
1 – 25 – 16	115	85	68	33	16	2	4	14	1.17
1 – 32 – 16	135	100	78	39	16	2	4	18	1.58
1 – 40 – 16	145	110	88	46	17	3	4	18	1.96
1 – 50 – 16	160	125	102	59	19	3	4	18	2.58
1 – 65 – 16	180	145	122	78	21	3	4	18	3.42
1 – 80 – 16	195	160	133	91	21	3	4	18	3.71
1 – 100 – 16	215	180	158	110	23	3	8	18	4.73
1 – 125 – 16	245	210	184	135	25	3	8	18	6.38
1 – 150 – 16	280	240	212	161	25	3	8	22	7.81
1 – 175 – 16	310	270	242	196	25	3	8	22	8.64
1 – 200 – 16	335	395	268	222	27	3	12	22	10.1
1 – 225 – 16	365	325	295	245	27	3	12	22	11.7
1 – 250 – 16	405	355	320	273	28	3	12	26	14.49
1 – 300 – 16	460	410	370	325	28	4	12	26	17.78
1 – 350 – 16	520	470	430	377	30	4	16	26	22.88
1 – 400 – 16	580	525	482	426	34	4	16	30	31
1 – 450 – 16	640	585	532	480	38	4	20	30	39.64
1 – 500 – 16	710	650	585	530	44	4	20	33	57.01
1 – 600 – 16	840	770	685	630	45	5	20	39	80.03
1 – 700 – 16	910	840	800	720	47	5	24	39	84.21
1 – 800 – 16	1020	950	905	820	49	5	24	39	104.4
1 – 900 – 16	1120	1050	1005	920	54	5	28	39	128.6
1 – 1000 – 16	1255	1170	1110	1020	58	5	28	45	179.4
1 – 1200 – 16	1485	1390	1330	1220	71	5	32	52	297.8

Dimension of GOST 12820-80 P25 Flat flange

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	d1 (mm)	b (mm)	h (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-25	90	60	42	15	14	2	4	14	0.63
1 – 15 – 25	105	65	47	19	14	2	4	14	0.7
1 – 20 – 25	105	75	58	26	16	2	4	14	0.98
1 – 25 – 25	115	85	68	33	16	2	4	14	1.17
1 – 32 – 25	135	100	78	39	18	2	4	18	1.77
1 – 40 – 25	115	110	88	46	19	3	4	18	2.18
1 – 50 – 25	160	125	102	59	21	3	4	18	2.71
1 – 65 – 25	180	145	122	78	21	3	8	18	3.22
1 – 80 – 25	195	160	133	91	23	3	8	18	4.06
1 – 100 – 25	230	190	158	110	25	3	8	22	5.92
1 – 125 – 25	270	220	184	135	27	3	8	26	8.26
1 – 150 – 25	300	250	212	161	27	3	8	26	10.12
1 – 175 – 25	330	280	242	196	29	3	12	26	11.49
1 – 200 – 25	360	310	278	222	29	3	12	26	13.34
1 – 225 – 25	395	340	305	245	31	3	12	30	16.93
1 – 250 – 25	425	370	335	273	31	3	12	30	18.9
1 – 300 – 25	485	430	390	325	32	4	16	30	23.95
1 – 350 – 25	550	490	450	377	38	4	16	33	34.35
1 – 400 – 25	610	550	505	426	40	4	16	33	44.62
1 – 450 – 25	660	600	555	480	44	4	20	33	51.8
1 – 500 – 25	730	660	615	530	48	4	20	39	67.3
1 – 600 – 25	840	770	720	630	49	5	20	39	90.87
1 – 700 – 25	960	875	820	720	55	5	24	45	126.8
1 – 800 – 25	1075	990	930	820	63	5	24	45	181.4

Looking for a reliable GOST 12820-80 flange manufacturer? Contact today for pricing and delivery

⬇️ Download GOST /ГОСТ 12820 PN6 0.6Mpa Plane flange / Flat flange Dimensions Now (PDF)

⬇️ Download GOST /ГОСТ 12820 PN10 1.0Mpa Plane flange / Flat flange Dimensions Now (PDF)

⬇️ Download GOST /ГОСТ 12820 PN16 1.6 Plane flange / Flat flange Dimensions Now (PDF)

⬇️ Download GOST /ГОСТ 12820 PN25 2.5 Plane flange / Flat flange Dimensions Now (PDF)

Related Products

• GOST 12821-80 Weld Neck Flanges
• GOST 12822-80 Loose Flanges
• GOST 33259 type 01 Flat Weld Flanges
• EN 1092-1 Type 01 Plate Flanges
• ASME B16.5 Slip On Flanges

GOST 12820-80 steel plate flat flanges for pipes provide a reliable and cost-effective solution for piping systems designed to GOST standards. With a wide DN range, multiple pressure ratings, and various material options, these flat flanges are suitable for a broad range of industrial applications.
For technical support, drawings, pricing, and fast delivery, contact us for GOST 12820-80 flange today.