GOST 12821-80 Steel butt welded flange,weld neck flanges

GOST 12821-80 Weld Neck Flanges Manufacturer – Premium Quality Flanges for Industrial Applications

We are a leading manufacturer and supplier of GOST 12821-80 flanges, specializing in high-quality weld neck flanges for high-pressure applications. Designed in accordance with Russian standards, GOST 12821-80 flanges are widely used in oil & gas, petrochemical, power generation, and heavy industrial sectors.

GOST 12821-80 Weld Neck Flanges are widely used in various industries due to their robust performance and long-lasting durability. As a trusted manufacturer, we provide high-quality weld neck flanges that meet international standards, ensuring reliability and safety in critical applications.

What Is GOST 12821-80?

GOST 12821-80 is a Russian standard that specifies the dimensions and tolerances for steel high-pressure weld neck flanges (Class PN 6 to PN 250). These flanges are typically used in pipeline systems where high strength and resistance to pressure and temperature are required.

GOST 12821-80 is a Russian standard that defines the dimensions and technical requirements for steel butt-welded flanges used in high-pressure piping systems. Free download GOST 12821-80 standard in PDF

GOST 12821-80 Flange specification

Type: Butt-welded flange (приварной встык) — equivalent to weld neck flanges in international standards (EN 109201 type 11)

Connection method: Welded to the pipe end by butt welding (not fillet weld)

Purpose: Ensures high strength, leak-proof, and stress-resistant connections

Pressure ratings:

PN 0.6 to PN 20.0 MPa (6 to 200 kgf/cm²)

Nominal diameter (DN):

Typically DN 10 to DN 1600

Sealing face types (per GOST 12815-80):

Type 1 – smooth face
Type 2 – protruding face
Type 3 – groove
Type 4 – tongue
Type 5 – ring joint
Type 6 – male face

Material:

Carbon steel :СТ20; СТ.3, 09Т2С
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

GOST 12821-80 Flange Dimensions

GOST 12821-80 Flange PN6 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-6	75	50	35	2	8	10	27	22	15	4	11	0.34
1 – 15 – 6	80	55	40	2	12	10	28	28	19	4	11	0.4
1 – 20 – 6	90	65	50	2	18	10	30	36	26	4	11	0.53
1 – 25 – 6	100	75	60	2	25	12	30	42	33	4	11	0.76
1 – 32 – 6	120	90	70	2	31	12	33	50	39	4	14	1.1
1 – 40 – 6	130	100	80	3	38	12	35	60	46	4	14	1.36
1 – 50 – 6	140	110	90	3	49	12	35	70	58	4	14	1.53
1 – 65 – 6	160	130	110	3	66	12	35	88	77	4	14	1.97
1 – 80 – 6	185	150	128	3	78	13	37	102	90	4	18	2.76
1 – 100 – 6	205	170	148	3	96	13	38	122	110	4	18	3.35
1 – 125 – 6	235	200	178	3	121	15	40	148	135	8	18	4.66
1 – 150 – 6	260	225	202	3	146	15	43	172	161	8	18	5.37
1 – 175 – 6	290	255	232	3	177	17	47	210	196	8	18	7.32
1 – 200 – 6	315	280	258	3	202	17	50	235	222	8	18	8.37
1 – 225 – 6	340	305	282	3	226	17	50	260	248	8	18	9.45
1 – 250 – 6	370	335	312	3	254	18	50	288	278	12	18	10.99
1 – 300 – 6	435	395	365	4	303	18	50	340	330	12	22	14.82
1 – 350 – 6	485	445	415	4	351	18	50	390	382	12	22	17.69
1 – 400 – 6	535	495	465	4	398	18	50	440	432	16	22	20.55
1 – 450 – 6	590	550	520	4	450	18	50	494	484	16	22	23.63
1 – 500 – 6	640	600	570	4	501	19	50	545	535	16	22	26.63
1 – 600 – 6	755	705	670	5	602	19	55	650	636	20	26	35.79
1 – 700 – 6	860	810	775	5	692	19	55	740	726	24	26	44.31
1 – 800 – 6	975	920	880	5	792	19	60	844	826	24	30	56.17
1 – 900 – 6	1075	1020	980	5	792	21	60	944	926	24	30	66.79
1 – 1000 – 6	1175	1120	1080	5	992	21	60	1044	1028	28	30	73.51
1 – 1200 – 6	1375	1340	1295	5	1192	23	70	1248	1228	32	33	111.4

GOST 12821-80 Flange PN10 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-10	90	60	42	2	8	10	33	25	15	4	14	0.5
1 – 15 – 10	95	65	47	2	12	10	33	33	19	4	14	0.58
1 – 20 – 10	105	75	58	2	18	12	38	30	26	4	14	0.87
1 – 25 – 10	115	85	68	2	25	12	38	45	33	4	14	1.05
1 – 32 – 10	135	100	78	2	31	13	40	55	39	4	18	1.54
1 – 40 – 10	145	110	88	3	38	13	42	62	46	4	18	1.83
1 – 50 – 10	160	125	102	3	49	13	42	76	58	4	18	2.26
1 – 65 – 10	180	145	122	3	66	15	45	94	77	4	18	3.17
1 – 80 – 10	195	160	133	3	78	15	47	105	90	4	18	3.67
1 – 100 – 10	215	180	158	3	96	17	48	126	110	8	18	4.7
1 – 125 – 10	245	210	184	3	121	19	57	158	135	8	18	6.71
1 – 150 – 10	280	240	212	3	146	19	57	180	161	8	22	8.17
1 – 175 – 10	310	270	242	3	177	19	57	210	196	8	22	9.71
1 – 200 – 10	335	295	268	3	202	19	58	240	222	8	22	11.35
1 – 225 – 10	365	325	295	3	226	19	60	268	248	8	22	13.24
1 – 250 – 10	390	350	320	3	254	21	60	290	278	12	22	14.64
1 – 300 – 10	440	400	370	4	303	22	60	345	330	12	22	18.66
1 – 350 – 10	500	460	430	4	351	22	60	400	382	16	22	24
1 – 400 – 10	565	515	482	4	398	22	60	445	432	16	26	30
1 – 450 – 10	615	565	532	4	450	22	65	500	484	20	26	33.33
1 – 500 – 10	670	620	585	4	501	24	65	550	535	20	26	39.2
1 – 600 – 10	780	725	685	5	602	24	65	650	636	20	30	48.8
1 – 700 – 10	895	840	800	5	692	25	65	744	726	24	30	65.26
1 – 800 – 10	1010	950	905	5	792	27	75	850	826	24	33	87.24
1 – 900 – 10	1110	1050	1005	5	892	29	80	950	926	28	33	103
1 – 1000 – 10	1220	1160	110	5	992	29	80	1050	1028	28	33	119.2
1 – 1200 – 10	1455	1380	1330	5	1192	33	90	1256	1228	32	39	179.9

GOST 12821-80 Flange PN16 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-16	90	60	42	2	8	12	33	26	15	4	14	0.59
1 – 15 – 16	95	65	47	2	12	12	33	33	19	4	14	0.68
1 – 20 – 16	105	75	58	2	18	12	36	30	26	4	14	0.87
1 – 25 – 16	115	85	68	2	25	12	38	45	33	4	14	1.05
1 – 32 – 16	135	100	78	2	31	13	40	55	39	4	18	1.54
1 – 40 – 16	145	110	88	3	38	13	42	64	46	4	18	1.85
1 – 50 – 16	160	125	102	3	49	13	45	76	58	4	18	2.28
1 – 65 – 16	180	145	122	3	66	15	47	94	77	4	18	3.19
1 – 80 – 16	195	160	133	3	78	17	50	110	90	4	18	4.21
1 – 100 – 16	215	180	158	3	96	17	50	130	110	8	18	4.9
1 – 125 – 16	245	210	184	3	121	19	57	156	135	8	18	6.75
1 – 150 – 16	280	240	212	3	146	19	57	180	161	8	22	8.3
1 – 175 – 16	310	270	242	3	177	21	57	210	196	8	22	10.37
1 – 200 – 16	335	395	268	3	202	21	58	240	222	12	22	11.79
1 – 225 – 16	365	325	295	3	226	21	65	268	248	12	22	14.12
1 – 250 – 16	405	355	320	3	254	23	65	292	278	12	26	17.36
1 – 300 – 16	460	410	370	4	303	24	66	346	330	12	26	22.76
1 – 350 – 16	520	470	430	4	351	28	70	400	382	16	26	32.04
1 – 400 – 16	580	525	482	4	398	32	75	450	432	16	30	43
1 – 450 – 16	640	585	532	4	450	34	85	506	484	20	30	54
1 – 500 – 16	710	650	585	4	501	38	90	559	535	20	33	70.97
1 – 600 – 16	840	770	685	5	602	41	90	660	636	20	33	99.3
1 – 700 – 16	910	840	800	5	692	43	95	750	726	24	39	105.9
1 – 800 – 16	1020	950	905	5	792	45	95	850	826	24	39	130.6
1 – 900 – 16	1120	1050	1005	5	892	47	110	958	926	28	39	157.8
1 – 1000 – 16	1255	1170	1110	5	992	49	110	1060	1028	28	45	203.4
1 – 1200 – 16	1485	1390	1330	5	1192	51	125	1268	1228	32	52	284.9

GOST 12821-80 Flange PN25 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1-10-25	90	60	42	2	8	14	33	26	15	4	14	0.68
1 – 15 – 25	105	65	47	2	12	14	33	30	19	4	14	0.79
1 – 20 – 25	105	75	58	2	18	14	34	38	26	4	14	0.97
1 – 25 – 25	115	85	68	2	25	14	36	45	33	4	14	1.18
1 – 32 – 25	135	100	78	2	31	16	43	56	39	4	18	1.83
1 – 40 – 25	115	110	88	3	38	16	45	64	46	4	18	2.19
1 – 50 – 25	160	125	102	3	49	17	45	76	58	4	18	2.78
1 – 65 – 25	180	145	122	3	66	19	50	96	77	8	18	3.71
1 – 80 – 25	195	160	133	3	78	19	52	110	90	8	18	4.44
1 – 100 – 25	230	190	158	3	96	21	58	132	110	8	22	6.51
1 – 125 – 25	270	220	184	3	121	23	65	160	135	8	26	9.41
1 – 150 – 25	300	250	212	3	146	25	68	186	161	8	26	12.52
1 – 175 – 25	330	280	242	3	177	25	70	216	196	12	26	13.88
1 – 200 – 25	360	310	278	3	202	27	75	245	222	12	26	17.44
1 – 225 – 25	395	340	305	3	226	29	75	270	248	12	30	21.56
1 – 250 – 25	425	370	335	3	254	29	75	300	278	12	30	24.4
1 – 300 – 25	485	430	390	4	303	32	80	352	330	16	30	33.29
1 – 350 – 25	550	490	450	4	351	36	85	406	382	16	33	46.57
1 – 400 – 25	610	550	505	4	398	40	100	464	432	16	33	64.81
1 – 450 – 25	660	600	555	4	450	42	100	515	484	20	33	72.26
1 – 500 – 25	730	660	615	4	500	44	105	570	535	20	39	88.91
1 – 600 – 25	840	770	720	5	600	49	115	670	636	20	39	123.7
1 – 700 – 25	960	875	820	5	690	53	125	766	726	24	45	166.8
1 – 800 – 25	1075	990	930	5	790	55	135	874	826	24	45	213.9
1 – 900 – 25	1185	1090	1030	5	892	57	145	980	926	28	52	252.9
1 – 1000 – 25	1315	1210	1140	5	992	59	150	1084	1028	28	56	312.1
1 – 1200 – 25	1525	1420	1350	5	1192	62	160	1288	1228	32	56	387.5

GOST 12821-80 Flange PN40 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1 – 10 – 40	90	60	42	2	8	14	33	26	15	4	14	0.68
1 – 15 – 40	95	65	47	2	12	14	33	30	19	4	14	0.79
1 – 20 – 40	105	75	58	2	18	14	34	38	26	4	14	0.97
1 – 25 – 40	115	85	68	2	25	14	36	45	33	4	14	1.18
1 – 32 – 40	135	100	78	2	31	16	43	56	39	4	18	1.83
1 – 40 – 40	145	110	88	3	38	16	45	64	46	4	18	2.19
1 – 50 – 40	160	125	102	3	48	17	45	76	58	4	18	2.81
1 – 65 – 40	180	145	122	3	66	19	50	96	77	8	18	3.71
1 – 80 – 40	195	160	133	3	78	21	55	112	90	8	18	4.8
1 – 100 – 40	230	190	158	3	96	23	65	138	110	8	22	7.4
1 – 125 – 40	270	220	184	3	120	25	65	160	135	8	26	10
1 – 150 – 40	300	250	212	3	145	27	68	186	161	8	26	13.03
1 – 175 – 40	350	295	242	3	177	33	85	226	196	12	30	20.75
1 – 200 – 40	375	320	285	3	200	35	85	250	222	12	30	24.44
1 – 225 – 40	415	355	315	3	226	37	95	280	248	12	33	31.33
1 – 250 – 40	445	385	345	3	252	39	98	310	278	12	33	37.59
1 – 300 – 40	510	450	410	4	301	42	112	368	330	16	33	57.1
1 – 350 – 40	570	510	465	4	351	48	116	418	382	16	33	70.34
1 – 400 – 40	655	585	535	4	398	54	135	480	432	16	39	106.8
1 – 450 – 40	680	610	560	4	448	56	135	530	484	20	39	107
1 – 500 – 40	755	670	615	4	495	58	140	580	535	20	45	132.3
1 – 600 – 40	890	795	735	5	595	58	140	686	636	20	52	181
1 – 700 – 40	995	900	810	5	695	63	160	790	726	24	52	228.3
1 – 800 – 40	1135	1030	960	5	795	71	190	908	826	24	56	343.7
1 – 900 – 40	1250	1140	1070	5	895	74	215	1024	926	28	56	436.5
1 – 1000 – 40	1360	1250	1180	5	995	77	235	1140	1028	28	56	540.8
1 – 1200 – 40	1575	1460	1380	5	1195	80	250	1350	1228	32	62	690.6

GOST 12821-80 Flange PN63 Dimensions

Nomenclature	D (mm)	D1 (mm)	D2 (mm)	h (mm)	d1 (mm)	b (mm)	h4 (mm)	Dm (mm)	Dn (mm)	Number of holes (n)	d (mm)	Weight, Kg
1 – 10 – 63	100	70	42	2	8	16	46	34	15	4	14	1.03
1 – 15 – 63	105	75	47	2	12	16	46	38	19	4	14	1.15
1 – 20 – 63	125	90	58	2	18	18	54	48	26	4	18	1.8
1 – 25 – 63	135	100	68	2	25	20	56	52	33	4	18	2.3
1 – 32 – 63	150	110	78	2	31	21	60	64	39	4	22	2.94
1 – 40 – 63	165	125	88	3	37	21	65	74	46	4	22	3.75
1 – 50 – 63	175	135	102	3	47	23	67	86	58	4	22	4.63
1 – 65 – 63	200	160	122	3	64	25	72	106	77	8	22	6.29
1 – 80 – 63	210	170	133	3	77	27	72	120	90	8	22	7.22
1 – 100 – 63	250	200	158	3	94	29	77	140	110	8	26	10.71
1 – 125 – 63	295	240	184	3	118	33	95	172	135	8	30	17.13
1 – 150 – 63	340	280	212	3	142	35	105	206	161	8	33	24.6
1 – 175 – 63	370	310	212	3	174	39	105	232	196	12	33	28.61
1 – 200 – 63	405	345	285	3	198	41	110	264	222	12	33	36.6
1 – 225 – 63	430	370	315	3	222	43	115	290	248	12	33	42.54
1 – 250 – 63	470	400	345	3	246	45	115	316	278	12	39	50.89
1 – 300 – 63	530	460	410	4	294	50	120	370	330	16	39	68.15
1 – 350 – 63	595	525	465	4	342	56	140	430	382	16	39	98.68
1 – 400 – 63	670	585	535	4	386	62	155	484	432	16	45	135.8
1 – 500 – 63	800	705	615	4	485	66	165	594	535	20	52	192.7
1 – 600 – 63	925	825	735	5	585	71	180	704	636	20	52	269.3
1 – 700 – 63	1045	930	840	5	685	76	225	820	726	24	56	300.9
1 – 800 – 63	1165	1050	960	5	785	85	225	920	826	24	62	463.9
1 – 900 – 63	1285	1170	1070	5	885	88	265	1050	926	28	62	954.4
1 – 1000 – 63	1415	1290	1180	5	985	92	280	1160	1028	28	70	980.6
1 – 1200 – 63	1665	1530	1380	5	1185	95	315	1386	1228	32	78	1264

Marking for Gost `12821-80` flanges

A flange marked:

Фланец 10-100-1 ГОСТ 12821-80

Means:

PN 10 MPa
DN 100
Sealing face type 1 (smooth)
Butt-welded flange per GOST 12821-80

GOST 12821-80 Standard English

⬇️ Download GOST 12821-80 Standard in English now (PDF)

And Gost `12821-80` flanges Dimension chart

⬇️ Download GOST 12821-80 Weld neck Flange PN6 Dimensions now (PDF)

⬇️ Download GOST 12821-80 Weld neck Flange PN10 Dimensions now (PDF)

⬇️ Download GOST 12821-80 Weld neck Flange PN16 Dimensions now (PDF)

⬇️ Download GOST 12821-80 Weld neck Flange PN25 Dimensions now (PDF)

⬇️ Download GOST 12821-80 Weld neck Flange PN40 Dimensions now (PDF)

⬇️ Download GOST 12821-80 Weld neck Flange PN63 Dimensions now (PDF)

Gost flat Flange

GOST /ГОСТ 12820 Plane flange / Flat flange Dimensions PN6 0.6Mpa

GOST /ГОСТ 12820 Plane flange / Flat flange Dimensions PN10 1.0Mpa

GOST /ГОСТ 12820 Plane flange / Flat flange Dimensions PN16 1.6Mpa

GOST /ГОСТ 12820 Plane flange / Flat flange Dimensions PN25 2.5Mpa

Gost 12821 Weld neck Flange

GOST /ГОСТ 12821 Welding neck flange Dimensions PN10 1.0Mpa

GOST /ГОСТ 12821 Welding neck flange Dimensions PN16 1.6Mpa

GOST /ГОСТ 12821 Welding neck flange Dimensions PN25 2.5Mpa

GOST /ГОСТ 12821 Welding neck flange Dimensions PN40 4.0Mpa

GOST /ГОСТ 12821 Welding neck flange Dimensions PN63 6.3Mpa

GOST /ГОСТ 12821 Welding neck flange Dimensions PN100 10Mpa

Gost Blind Flange

GOST /ГОСТ 12836 Blind Flange Dimensions PN10 1.0Mpa

GOST /ГОСТ 12836 Blind Flange Dimensions PN16 1.6Mpa

GOST /ГОСТ 12836 Blind Flange Dimensions PN25 2.5Mpa

GOST /ГОСТ 12836 Blind Flange Dimensions PN40 4.0Mpa

Gost 33259 Flange

Gost 33259 type 01 Plate Flange

Gost 33259 type 11 Weld Neck Flange

GOST 12821-80 Flanges are weld neck (WN) steel flanges designed for high-pressure pipeline systems, manufactured in accordance with Russian Standard GOST 12821-80. These flanges are widely used in oil & gas, power generation, chemical, and shipbuilding industries for secure, leak-proof connections between pipes, valves, and pressure vessels.