Large Diameter Weld Neck Flange

Size Range: DN650-DN1500 (26″- 60″)
Pressure Class: PN20-PN420 (Class 150 – Class 2500)
Sealing Faces: RF, FF, MFM, TG, RJ
Standards: ASME B16.5, ASME B16.47 Series A/B, EN1092-1, HG/T20592, HG/T20615, HG/T20623, JIS B2220
Materials: 20#, A105, LF2, F11/F22, 304, 316L, 2205, 2507, Alloy20, Hastelloy C, TA2
Media: Steam, oil, gas, acid/alkali, seawater, organic solvent, cryogenic medium
Temperature: -196℃ ~ 1000℃
Application: Oil&gas, petrochemical, power plant, marine, municipal water, metallurgy, environmental protection

Product details

Large Diameter Weld Neck Flange, also known as Large High Neck Flange, is a heavy-duty forged weld neck flange designed for large-diameter pressure piping systems.

In the industry, it is generally defined as DN650 and above (NPS 26 and larger). The flange is connected to the pipeline through a tapered long neck and full penetration butt welding, providing excellent mechanical strength, sealing reliability, and pressure-bearing capability.

It is widely recognized as the preferred flange solution for large-diameter pipelines operating under high temperature, high pressure, vibration, and corrosive conditions.

The flange adopts a long tapered hub design, which provides a smooth transition between the flange body and the pipeline. This structure effectively distributes stress, reduces stress concentration, and improves resistance to: “High-pressure service conditions，High-temperature operation，Pipeline vibration and mechanical loads，Thermal expansion and contraction cycles，Corrosive and demanding environments”.

The welded joint between the flange neck and pipe is achieved through full penetration butt welding, ensuring the weld strength is equivalent to the parent pipe material and providing superior structural integrity.

Product Specifications

Note: The flange inner diameter (B) is determined by the wall thickness of the steel pipe and shall be specified by the user at the time of ordering.（Unit: mm）

AWN-150LB-900LB（Flange Series A / Flange Series B )

DN	NPS	Type/Class	Part No	A	D	K	L	Th	n	C	B	N	R	H
650	26	AWN-150LB-SFT	XLXAWN150SFT26	660.4	870	806.4	36	M33	24	66.7	/	676	10	119
700	28	AWN-150LB-SFT	XLXAWN150SFT28	711.2	925	863.6	36	M33	28	69.9	/	727	11	124
750	30	AWN-150LB-SFT	XLXAWN150SFT30	762.0	985	914.4	36	M33	28	73.1	/	781	11	135
800	32	AWN-150LB-SFT	XLXAWN150SFT32	812.8	1060	977.9	42	M39	28	79.4	/	832	11	143
850	34	AWN-150LB-SFT	XLXAWN150SFT34	863.6	1110	1028.7	42	M39	32	81.0	/	883	13	148
900	36	AWN-150LB-SFT	XLXAWN150SFT36	914.4	1170	1085.8	42	M39	32	88.9	/	933	13	156
950	38	AWN-150LB-SFT	XLXAWN150SFT38	965.2	1240	1149.4	42	M39	32	85.8	/	991	13	156
1000	40	AWN-150LB-SFT	XLXAWN150SFT40	1016.0	1290	1200.2	42	M39	36	88.9	/	1041	13	162
1050	42	AWN-150LB-SFT	XLXAWN150SFT42	1066.8	1345	1257.3	42	M39	36	95.3	/	1092	13	170
1100	44	AWN-150LB-SFT	XLXAWN150SFT44	1117.6	1405	1314.4	42	M39	40	100.1	/	1143	13	176
1150	46	AWN-150LB-SFT	XLXAWN150SFT46	1168.4	1455	1365.2	42	M39	40	101.6	/	1197	13	184
1200	48	AWN-150LB-SFT	XLXAWN150SFT48	1219.2	1510	1422.4	42	M39	44	106.4	/	1248	13	191
1250	50	AWN-150LB-SFT	XLXAWN150SFT50	1270.0	1570	1479.6	48	M45	44	109.6	/	1302	13	202
1300	52	AWN-150LB-SFT	XLXAWN150SFT52	1320.8	1625	1536.7	48	M45	44	114.3	/	1353	13	208
1350	54	AWN-150LB-SFT	XLXAWN150SFT54	1371.6	1685	1593.8	48	M45	44	119.1	/	1403	13	214
1400	56	AWN-150LB-SFT	XLXAWN150SFT56	1422.4	1745	1651.0	48	M45	48	122.3	/	1457	13	227
1450	58	AWN-150LB-SFT	XLXAWN150SFT58	1473.2	1805	1708.2	48	M45	48	127.0	/	1508	13	233
1500	60	AWN-150LB-SFT	XLXAWN150SFT60	1524.0	1855	1759.0	48	M45	52	130.2	/	1559	13	238
650	26	BWN-150LB-SFT	XLXBWN150SFT26	661.9	785	744.5	22	M20	36	39.8	/	684	10	87
700	28	BWN-150LB-SFT	XLXBWN150SFT28	712.7	835	795.3	22	M20	40	43.0	/	735	10	94
750	30	BWN-150LB-SFT	XLXBWN150SFT30	763.5	885	846.1	22	M20	44	43.0	/	787	10	98
800	32	BWN-150LB-SFT	XLXBWN150SFT32	814.3	940	900.1	22	M20	48	44.6	/	840	10	106
850	34	BWN-150LB-SFT	XLXBWN150SFT34	865.1	1005	957.3	26	M24	40	47.7	/	892	10	109
900	36	BWN-150LB-SFT	XLXBWN150SFT36	915.9	1055	1009.6	26	M24	44	50.9	/	945	10	116
950	38	BWN-150LB-SFT	XLXBWN150SFT38	968.2	1125	1070.0	30	M27	40	52.5	/	997	10	122
1000	40	BWN-150LB-SFT	XLXBWN150SFT40	1019.0	1175	1120.8	30	M27	44	54.1	/	1049	10	127
1050	42	BWN-150LB-SFT	XLXBWN150SFT42	1069.8	1225	1171.6	30	M27	48	57.3	/	1102	11	132
1100	44	BWN-150LB-SFT	XLXBWN150SFT44	1120.6	1275	1222.4	30	M27	52	58.9	/	1153	11	135
1150	46	BWN-150LB-SFT	XLXBWN150SFT46	1171.4	1340	1284.3	33	M30	40	60.4	/	1205	11	143
1200	48	BWN-150LB-SFT	XLXBWN150SFT48	1222.2	1390	1335.1	33	M30	44	63.6	/	1257	11	148
1250	50	BWN-150LB-SFT	XLXBWN150SFT50	1273.0	1445	1385.9	33	M30	48	66.8	/	1308	11	152
1300	52	BWN-150LB-SFT	XLXBWN150SFT52	1323.8	1495	1436.7	33	M30	52	68.4	/	1360	11	156
1350	54	BWN-150LB-SFT	XLXBWN150SFT54	1374.6	1550	1492.2	33	M30	56	70.0	/	1413	11	160
1400	56	BWN-150LB-SFT	XLXBWN150SFT56	1425.4	1600	1543.0	33	M30	60	71.6	/	1465	14	165
1450	58	BWN-150LB-SFT	XLXBWN150SFT58	1476.2	1675	1611.3	36	M33	48	73.1	/	1516	14	173
1500	60	BWN-150LB-SFT	XLXBWN150SFT60	1527.0	1725	1662.1	36	M33	52	74.7	/	1570	14	178
650	26	AWN-300LB-SFT	XLXAWN300SFT26	660.4	970	876.3	45	M42	28	77.8	/	721	10	183
700	28	AWN-300LB-SFT	XLXAWN300SFT28	711.2	1035	939.8	45	M42	28	84.2	/	775	11	195
750	30	AWN-300LB-SFT	XLXAWN300SFT30	762.0	1090	997.0	48	M45	28	90.5	/	827	11	208
800	32	AWN-300LB-SFT	XLXAWN300SFT32	812.8	1150	1054.1	51	M48	28	96.9	/	881	11	221
850	34	AWN-300LB-SFT	XLXAWN300SFT34	863.6	1205	1104.9	51	M48	28	100.1	/	937	13	230
900	36	AWN-300LB-SFT	XLXAWN300SFT36	914.4	1270	1168.4	55	M52	32	103.2	/	991	13	240
950	38	AWN-300LB-SFT	XLXAWN300SFT38	965.2	1170	1092.2	42	M39	32	106.4	/	994	13	179
1000	40	AWN-300LB-SFT	XLXAWN300SFT40	1016.0	1240	1155.7	45	M42	32	112.8	/	1048	13	192
1050	42	AWN-300LB-SFT	XLXAWN300SFT42	1066.8	1290	1206.5	45	M42	32	117.5	/	1099	13	198
1100	44	AWN-300LB-SFT	XLXAWN300SFT44	1117.6	1355	1263.6	48	M45	32	122.3	/	1149	13	205
1150	46	AWN-300LB-SFT	XLXAWN300SFT46	1168.4	1415	1320.8	51	M48	28	127.0	/	1203	13	214
1200	48	AWN-300LB-SFT	XLXAWN300SFT48	1219.2	1465	1371.6	51	M48	32	131.8	/	1254	13	222
1250	50	AWN-300LB-SFT	XLXAWN300SFT50	1270.0	1530	1428.8	55	M52	32	138.2	/	1305	13	230
1300	52	AWN-300LB-SFT	XLXAWN300SFT52	1320.8	1580	1479.6	55	M52	32	142.9	/	1356	13	237
1350	54	AWN-300LB-SFT	XLXAWN300SFT54	1371.6	1660	1549.4	60	M56	28	150.9	/	1410	13	251
1400	56	AWN-300LB-SFT	XLXAWN300SFT56	1422.4	1710	1600.2	60	M56	28	152.4	/	1464	13	259
1450	58	AWN-300LB-SFT	XLXAWN300SFT58	1473.2	1760	1651.0	60	M56	32	157.2	/	1514	13	265
1500	60	AWN-300LB-SFT	XLXAWN300SFT60	1524.0	1810	1701.8	60	M56	32	162.0	/	1565	13	271
650	26	BWN-300LB-SFT	XLXBWN300SFT26	665.2	865	803.3	36	M33	32	87.4	/	702	14	143
700	28	BWN-300LB-SFT	XLXBWN300SFT28	716.0	920	857.2	36	M33	36	87.4	/	756	14	148
750	30	BWN-300LB-SFT	XLXBWN300SFT30	768.4	990	920.8	39	M36×3	36	92.1	/	813	14	156
800	32	BWN-300LB-SFT	XLXBWN300SFT32	819.2	1055	977.9	42	M39×3	32	101.6	/	864	16	167
850	34	BWN-300LB-SFT	XLXBWN300SFT34	870.0	1110	1031.9	42	M39×3	36	101.6	/	918	16	171
900	36	BWN-300LB-SFT	XLXBWN300SFT36	920.8	1170	1089.0	45	M42x3	32	101.6	/	965	16	179
950	38	BWN-300LB-SFT	XLXBWN300SFT38	971.6	1220	1139.8	45	M42×3	36	109.6	/	1016	16	191
1000	40	BWN-300LB-SFT	XLXBWN300SFT40	1022.4	1275	1190.6	45	M42×3	40	114.3	/	1067	16	197
1050	42	BWN-300LB-SFT	XLXBWN300SFT42	1074.7	1335	1244.6	48	M45×3	36	117.5	/	1118	16	203
1100	44	BWN-300LB-SFT	XLXBWN300SFT44	1125.5	1385	1295.4	48	M45×3	40	125.5	/	1173	16	213
1150	46	BWN-300LB-SFT	XLXBWN300SFT46	1176.3	1460	1365.2	51	M48×3	36	127.0	/	1229	16	221
1200	48	BWN-300LB-SFT	XLXBWN300SFT48	1227.1	1510	1416.0	51	M48×3	40	127.0	/	1278	16	222
1250	50	BWN-300LB-SFT	XLXBWN300SFT50	1277.9	1560	1466.8	51	M48×3	44	136.6	/	1330	16	233
1300	52	BWN-300LB-SFT	XLXBWN300SFT52	1328.7	1615	1517.6	51	M48×3	48	141.3	/	1383	16	241
1350	54	BWN-300LB-SFT	XLXBWN300SFT54	1379.5	1675	1578.0	51	M48×3	48	145.0	/	1435	16	238
1400	56	BWN-300LB-SFT	XLXBWN300SFT56	1430.3	1765	1651.0	60	M56×3	36	152.4	/	1494	17	267
1450	58	BWN-300LB-SFT	XLXBWN300SFT58	1481.1	1825	1712.9	60	M56×3	40	152.4	/	1548	17	273
1500	60	BWN-300LB-SFT	XLXBWN300SFT60	1557.3	1880	1763.7	60	M56×3	40	149.3	/	1599	17	270
650	26	AWN-600LB-SFT	XLXAWN600SFT26	660.4	1015	914.4	51	M48	28	108.0	/	748	13	222
700	28	AWN-600LB-SFT	XLXAWN600SFT28	711.2	1075	965.2	55	M52	28	111.2	/	803	13	235
750	30	AWN-600LB-SFT	XLXAWN600SFT30	762.0	1130	1022.4	55	M52	28	114.3	/	862	13	248
800	32	AWN-600LB-SFT	XLXAWN600SFT32	812.8	1195	1079.5	60	M56	28	117.5	/	918	13	260
850	34	AWN-600LB-SFT	XLXAWN600SFT34	863.6	1245	1130.3	60	M56	28	120.7	/	973	14	270
900	36	AWN-600LB-SFT	XLXAWN600SFT36	914.4	1315	1193.8	68	M64	28	123.9	/	1032	14	283
950	38	AWN-600LB-SFT	XLXAWN600SFT38	965.2	1270	1162.0	60	M56	28	152.4	/	1022	14	254
1000	40	AWN-600LB-SFT	XLXAWN600SFT40	1016.0	1320	1212.8	60	M56	32	158.8	/	1073	14	264
1050	42	AWN-600LB-SFT	XLXAWN600SFT42	1066.8	1405	1283.7	68	M64	28	168.3	/	1127	14	279
1100	44	AWN-600LB-SFT	XLXAWN600SFT44	1117.6	1455	1333.5	68	M64	32	173.1	/	1181	14	289
1150	46	AWN-600LB-SFT	XLXAWN600SFT46	1168	1510	1391	68	M64	32	179	/	1235	14	300
1200	48	AWN-600LB-SFT	XLXAWN600SFT48	1219	1595	1461	74	M70	32	189	/	1289	14	316
1250	50	AWN-600LB-SFT	XLXAWN600SFT50	1270	1670	1524	80	M76	28	197	/	1343	14	329
1300	52	AWN-600LB-SFT	XLXAWN600SFT52	1321	1720	1575	80	M76	32	203	/	1394	14	337
1350	54	AWN-600LB-SFT	XLXAWN600SFT54	1372	1780	1632	80	M76	32	210	/	1448	14	349
1400	56	AWN-600LB-SFT	XLXAWN600SFT56	1422	1855	1695	86	M82	32	218	/	1502	16	362
1450	58	AWN-600LB-SFT	XLXAWN600SFT58	1473	1905	1746	86	M82	32	222	/	1553	16	370
1500	60	AWN-600LB-SFT	XLXAWN600SFT60	1524	1995	1822	94	M90	28	233	/	1610	17	389
650	26	BWN-600LB-SFT	XLXBWN600SFT26	660.4	890	806.4	48	M42×3	28	111.2	/	698	13	181
700	28	BWN-600LB-SFT	XLXBWN600SFT28	711.2	950	863.6	48	M45×3	28	115.9	/	752	13	190
750	30	BWN-600LB-SFT	XLXBWN600SFT30	762.0	1020	927.1	51	M48×3	28	125.5	/	806	13	205
800	32	BWN-600LB-SFT	XLXBWN600SFT32	812.8	1085	984.2	55	M52×3	28	130.2	/	860	13	216
850	34	BWN-600LB-SFT	XLXBWN600SFT34	863.6	1160	1054.1	60	M56×3	24	141.3	/	914	14	233
900	36	BWN-600LB-SFT	XLXBWN600SFT36	914.4	1215	1104.9	60	M56×3	28	146.1	/	968	14	243
650	26	AWN-900LB-SFT	XLXAWN900SFT26	660.4	1085	952.5	74	M70	20	139.7	/	775	11	286
700	28	AWN-900LB-SFT	XLXAWN900SFT28	711.2	1170	1022.4	80	M76	20	142.9	/	832	13	298
750	30	AWN-900LB-SFT	XLXAWN900SFT30	762.0	1230	1085.9	80	M76	20	149.3	/	889	13	311
800	32	AWN-900LB-SFT	XLXAWN900SFT32	812.8	1315	1155.7	86	M82	20	158.8	/	946	13	330
850	34	AWN-900LB-SFT	XLXAWN900SFT34	863.6	1395	1225.6	94	M90	20	165.1	/	1006	14	349
900	36	AWN-900LB-SFT	XLXAWN900SFT36	914.4	1460	1289.1	94	M90	20	171.5	/	1064	14	362
950	38	AWN-900LB-SFT	XLXAWN900SFT38	965.2	1460	1289.1	94	M90	20	190.5	/	1073	19	352
1000	40	AWN-900LB-SFT	XLXAWN900SFT40	1016.0	1510	1339.9	94	M90	24	196.9	/	1127	21	364
650	26	BWN-900LB-SFT	XLXBWN900SFT26	660.4	1020	901.7	68	M64×3	20	135.0	/	743	11	259
700	28	BWN-900LB-SFT	XLXBWN900SFT28	711.2	1105	971.6	74	M70×3	20	147.7	/	797	13	276
750	30	BWN-900LB-SFT	XLXBWN900SFT30	762.0	1180	1035.0	80	M76×3	20	155.6	/	851	13	289
800	32	BWN-900LB-SFT	XLXBWN900SFT32	812.8	1240	1092.2	80	M76×3	20	160.4	/	908	13	303
850	34	BWN-900LB-SFT	XLXBWN900SFT34	863.6	1315	1155.7	86	M82×3	20	171.5	/	962	14	319
900	36	BWN-900LB-SFT	XLXBWN900SFT36	914.4	1345	1200.2	80	M76×3	24	173.1	/	1016	14	325

Manufactured by integral forging process for high strength and material consistency. Designed for heavy-duty pressure piping applications.

Provides excellent resistance to fatigue, vibration, and pressure fluctuations. Available in various materials and pressure classes according to international standards.

It delivers the best pressure-bearing performance across all working conditions. Among all flange types, it boasts top-tier resistance to vibration, pressure fluctuation, and thermal fatigue. It serves as the only reliable option for large pipelines connected to pump outlets, compressors and reciprocating units.

The weld joints allow 100% non-destructive testing via RT radiographic inspection and UT ultrasonic inspection, meeting the NDT acceptance criteria for special equipment on high-pressure hazardous chemical pipelines. Such full weld inspection is not feasible for slip-on flanges and threaded flanges.

Large Diameter Weld Neck Flange

Product details

Product Specifications

AWN-150LB-900LB（Flange Series A / Flange Series B )

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