Inconel 625 Lap Joint Flange Features and Specifications

This article details the properties and ASME B16.5 specifications of Inconel 625 lap joint flanges.

Corrosion Resistance

Inconel 625 is virtually immune to chloride-ion stress corrosion cracking. The high molybdenum content provides exceptional resistance to pitting and crevice corrosion, while the nickel content ensures stability in both oxidizing and reducing environments.

Mechanical Properties

Tensile Strength: 827 MPa (120 ksi)

Yield Strength (0.2% Offset): 414 MPa (60 ksi)

Density: 8.44 g/cm³ (0.305 lb/in³)

Temperature Range

Inconel 625 maintains its mechanical properties from cryogenic temperatures up to 982°C (1800°F), making it one of the most versatile alloys in our production lineup.

Tables below detail dimensions in millimeters, with weights in kilograms. For custom configurations or RTJ facing, contact us.

ASME B165 Inconel 625 Lap Joint Flange Dimensions

Class 150

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	90	30	22.9	22.9	11.2	22.9	3	4	5/8	1/2	60.3	0.9
3/4	20	100	38	28.2	28.2	12.7	28.2	3	4	5/8	1/2	69.9	1.0
1	25	110	49	34.9	34.9	14.3	34.9	3	4	5/8	1/2	79.4	1.0
1 1/4	32	115	59	43.7	43.7	15.9	43.7	5	4	5/8	1/2	88.9	1.5
1 1/2	40	125	65	50	50	17.5	50	6	4	5/8	1/2	98.4	1.5
2	50	150	78	62.5	62.5	19.1	62.5	8	4	3/4	5/8	120.7	2.5
2 1/2	65	180	90	75.4	75.4	22.3	75.4	8	4	3/4	5/8	139.7	3.4
3	80	190	108	91.4	91.4	23.9	91.4	10	4	3/4	5/8	152.4	4.0
3 1/2	90	215	122	104.1	104.1	23.9	104.1	11	8	3/4	5/8	177.8	5.4
4	100	230	135	116.8	116.8	23.9	116.8	11	8	3/4	5/8	190.5	6.4
5	125	255	164	144.4	144.4	23.9	144.4	11	8	7/8	3/4	215.9	7.3
6	150	280	192	171.4	171.4	25.4	171.4	13	8	7/8	3/4	241.3	9.3
8	200	345	246	222.2	222.2	28.6	222.2	13	8	7/8	3/4	298.5	14.8
10	250	405	305	277.4	277.4	30.2	277.4	13	12	1	7/8	362	21.0
12	300	485	365	328.2	328.2	31.8	328.2	13	12	1	7/8	431.8	31.3
14	350	535	400	360.2	360.2	35	360.2	13	12	1 1/8	1	476.3	44.3
16	400	595	457	411.2	411.2	36.6	411.2	13	16	1 1/8	1	539.8	58.3
18	450	635	505	462.3	462.3	39.7	462.3	13	16	1 1/4	1 1/8	577.9	63.7
20	500	700	559	514.4	514.4	42.9	514.4	13	20	1 1/4	1 1/8	635	81.0
24	600	815	663	616	616	47.9	616	13	20	1 3/8	1 1/4	749.3	108

Class 300

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	95	38	22.9	22.9	14.3	22.9	3	4	5/8	1/2	66.7	1.3
3/4	20	115	48	28.2	28.2	15.9	28.2	3	4	3/4	5/8	82.6	1.5
1	25	125	54	34.9	34.9	17.5	34.9	3	4	3/4	5/8	88.9	1.5
1 1/4	32	135	64	43.7	43.7	19.1	43.7	5	4	3/4	5/8	98.4	1.9
1 1/2	40	155	70	50	50	20.7	50	6	4	7/8	3/4	114.3	2.9
2	50	165	84	62.5	62.5	22.3	62.5	8	8	3/4	5/8	127	3.5
2 1/2	65	190	100	75.4	75.4	25.4	75.4	8	8	7/8	3/4	149.2	5.0
3	80	210	117	91.4	91.4	28.6	91.4	10	8	7/8	3/4	168.3	6.4
3 1/2	90	230	133	104.1	104.1	30.2	104.1	11	8	7/8	3/4	184.2	8.3
4	100	255	146	116.8	116.8	31.8	116.8	11	8	7/8	3/4	200	10.8
5	125	280	178	144.4	144.4	35	144.4	11	8	7/8	3/4	235	13.7
6	150	320	206	171.4	171.4	36.6	171.4	13	12	7/8	3/4	269.9	19.1
8	200	380	260	222.2	222.2	41.3	222.2	13	12	1	7/8	330.2	28.1
10	250	445	321	277.4	277.4	47.7	277.4	13	16	1 1/8	1	387.4	38.9
12	300	520	375	328.2	328.2	50.8	328.2	13	16	1 1/4	1 1/8	450.8	56.2
14	350	585	425	360.2	360.2	54	360.2	13	20	1 1/4	1 1/8	514.4	81.0
16	400	650	483	411.2	411.2	57.2	411.2	13	20	1 3/8	1 1/4	571.5	92.9
18	450	710	533	462.3	462.3	60.4	462.3	13	24	1 3/8	1 1/4	628.6	122
20	500	775	587	514.4	514.4	63.5	514.4	13	24	1 3/8	1 1/4	685.8	154
24	600	915	702	616	616	69.9	616	13	24	1 5/8	1 1/2	812.8	233

Class 400

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	95	38	22.9	22.9	14.3	22.9	3	4	5/8	1/2	66.7	1.4
3/4	20	115	48	28.2	28.2	15.9	28.2	3	4	3/4	5/8	82.6	1.6
1	25	125	54	34.9	34.9	17.5	34.9	3	4	3/4	5/8	88.9	1.9
1 1/4	32	135	64	43.7	43.7	20.7	43.7	5	4	3/4	5/8	98.4	2.5
1 1/2	40	155	70	50	50	22.3	50	6	4	7/8	3/4	114.3	3.5
2	50	165	84	62.5	62.5	25.4	62.5	8	8	3/4	5/8	127	4.4
2 1/2	65	190	100	75.4	75.4	28.6	75.4	8	8	7/8	3/4	149.2	6.4
3	80	210	117	91.4	91.4	31.8	91.4	10	8	7/8	3/4	168.3	7.9
3 1/2	90	230	133	104.1	104.1	35	104.1	10	8	1	7/8	184.2	10.4
4	100	255	146	116.8	116.8	35	116.8	11	8	1	7/8	200	12.7
5	125	280	178	144.4	144.4	38.1	144.4	11	8	1	7/8	235	15.2
6	150	320	206	171.4	171.4	41.3	171.4	13	12	1	7/8	269.9	21.6
8	200	380	260	222.2	222.2	47.7	222.2	13	12	1 1/8	1	330	33.5
10	250	445	321	277.4	277.4	54	277.4	13	16	1 1/4	1 1/8	387.4	46.4
12	300	520	375	328.2	328.2	57.2	328.2	13	16	1 3/8	1 1/4	450.8	63.7
14	350	585	425	360.2	360.2	60.4	360.2	13	20	1 3/8	1 1/4	514.4	88.6
16	400	650	483	411.2	411.2	63.5	411.2	13	20	1 1/2	1 3/8	571.5	116
18	450	710	533	462.3	462.3	66.7	462.3	13	24	1 1/2	1 3/8	628.6	140
20	500	775	587	514.4	514.4	69.9	514.4	13	24	1 5/8	1 1/2	685.8	169
24	600	915	702	616	616	76.2	616	13	24	1 7/8	1 3/4	812.8	250

Class 600

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	95	38	22.9	22.9	14.3	22.9	3	4	5/8	1/2	66.7	1.4
3/4	20	115	48	28.2	28.2	15.9	28.2	3	4	3/4	5/8	82.6	1.5
1	25	125	54	34.9	34.9	17.5	34.9	3	4	3/4	5/8	88.9	1.9
1 1/4	32	135	64	43.7	43.7	20.7	43.7	5	4	3/4	5/8	98.4	2.5
1 1/2	40	155	70	50	50	22.3	50	6	4	7/8	3/4	114.3	3.5
2	50	165	84	62.5	62.5	25.4	62.5	8	8	3/4	5/8	127	4.4
2 1/2	65	190	100	75.4	75.4	28.6	75.4	8	8	7/8	3/4	149.2	6.4
3	80	210	117	91.4	91.4	31.8	91.4	10	8	7/8	3/4	168.3	7.9
3 1/2	90	230	133	104.1	104.1	35	104.1	11	8	1	7/8	184.2	10.4
4	100	275	152	116.8	116.8	38.1	116.8	11	8	1	7/8	215.9	18.1
5	125	330	189	144.4	144.4	44.5	144.4	11	8	1 1/8	1	266.7	31.3
6	150	355	222	171.4	171.4	47.7	171.4	13	12	1 1/8	1	292.1	38.9
8	200	420	273	222.2	222.2	55.6	222.2	13	12	1 1/4	1 1/8	349.2	56.2
10	250	510	343	277.4	277.4	63.5	277.4	13	16	1 3/8	1 1/4	431.8	83.2
12	300	560	400	328.2	328.2	66.7	328.2	13	20	1 3/8	1 1/4	489	98.3
14	350	605	432	360.2	360.2	69.9	360.2	13	20	1 1/2	1 3/8	527	113
16	400	705	495	411.2	411.2	76.2	411.2	13	20	1 5/8	1 1/2	603.2	162
18	450	745	546	462.3	462.3	82.6	462.3	13	20	1 3/4	1 5/8	654	196
20	500	815	610	514.4	514.4	88.9	514.4	13	24	1 3/4	1 5/8	723.9	251
24	600	940	718	616	616	101.6	616	13	24	2	1 7/8	838.2	358

Class 900

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	120	38	22.9	22.9	22.3	22.9	3	4	7/8	3/4	82.6	1.9
3/4	20	130	44	28.2	28.2	25.4	28.2	3	4	7/8	3/4	88.9	2.5
1	25	150	52	34.9	34.9	28.6	34.9	3	4	1	7/8	101.6	3.9
1 1/4	32	160	64	43.7	43.7	28.6	43.7	5	4	1	7/8	111.1	4.4
1 1/2	40	180	70	50	50	31.8	50	6	4	1 1/8	1	123.8	5.9
2	50	215	105	62.5	62.5	38.1	62.5	8	8	1	7/8	165.1	12.4
2 1/2	65	245	124	75.4	75.4	41.3	75.4	8	8	1 1/8	1	190.5	17.8
3	80	240	127	91.4	91.4	38.1	91.4	10	8	1	7/8	190.5	12.9
4	100	290	159	116.8	116.8	44.5	116.8	11	8	1 1/4	1 1/8	235	25.9
5	125	350	190	144.4	144.4	50.8	144.4	11	8	1 3/8	1 1/4	279.4	41.0
6	150	380	235	171.4	171.4	55.6	171.4	13	12	1 1/4	1 1/8	317.5	54.0
8	200	470	298	222.2	222.2	63.5	222.2	13	12	1 1/2	1 3/8	393.7	84.2
10	250	545	368	277.4	277.4	69.9	277.4	13	16	1 1/2	1 3/8	469.9	121
12	300	610	419	328.2	328.2	79.4	328.2	13	20	1 1/2	1 3/8	533.4	160
14	350	640	451	360.2	360.2	85.8	360.2	13	20	1 5/8	1 1/2	558.8	196
16	400	705	508	411.2	411.2	88.9	411.2	13	20	1 3/4	1 5/8	616	208
18	450	785	565	462.3	462.3	101.6	462.3	13	20	2	1 7/8	685.8	278
20	500	855	622	514.4	514.4	108	514.4	13	20	2 1/8	2	749.3	342
24	600	1040	749	616	616	139.7	616	13	20	2 1/2	2 1/4	901.7	656

Class 1500

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	120	38	22.9	22.9	22.3	22.9	3	4	7/8	3/4	82.6	1.9
3/4	20	130	44	28.2	28.2	25.4	28.2	3	4	7/8	3/4	88.9	2.5
1	25	150	52	34.9	34.9	28.6	34.9	3	4	1	7/8	101.6	4.0
1 1/4	32	160	64	43.7	43.7	28.6	43.7	5	4	1	7/8	111.1	4.4
1 1/2	40	180	70	50	50	31.8	50	6	4	1 1/8	1	123.8	5.9
2	50	215	105	62.5	62.5	38.1	62.5	8	8	1	7/8	165.1	10.6
2 1/2	65	245	124	75.4	75.4	41.3	75.4	8	8	1 1/8	1	190.5	17.7
3	80	265	133	91.4	91.4	47.7	91.4	10	8	1 1/4	1 1/8	203.2	23.5
4	100	310	162	116.8	116.8	54	116.8	11	8	1 3/8	1 1/4	241.3	35.6
5	125	375	197	144.4	144.4	73.1	144.4	11	8	1 5/8	1 1/2	292.1	63.7
6	150	395	229	171.4	171.4	82.6	171.4	13	12	1 1/2	1 3/8	317.5	81.0
8	200	485	292	222.2	222.2	92.1	222.2	13	12	1 3/4	1 5/8	393.7	127
10	250	585	368	277.4	277.4	108	277.4	13	12	2	1 7/8	482.6	214
12	300	675	451	328.2	328.2	123.9	328.2	13	16	2	1 7/8	571.5	285
14	350	750	495	360.2	360.2	133.4	360.2	13	16	2 1/4	2	635	368
16	400	825	552	411.2	411.2	146.1	411.2	13	16	2 1/2	2 1/4	704.8	490
18	450	915	597	462.3	462.3	162	462.3	13	16	2 3/4	2 1/2	774.7	637
20	500	985	641	514.4	514.4	177.8	514.4	13	16	3	2 3/4	831.8	854
24	600	1170	762	616	616	203.2	616	13	16	3 1/2	3 1/4	990.6	1347

Class 2500

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Hub Dia. Begin	Hub Dia. Top	Length Hub	Bore Dia.	Fillet Radius	No. of Holes	Dia. of Holes	Dia. of Bolts	Dia. of Bolt Circle	Approx. Weight Kg
1/2	15	135	43	22.9	22.9	30.2	22.9	3	4	7/8	3/4	88.9	3.5
3/4	20	140	51	28.2	28.2	31.8	28.2	3	4	7/8	3/4	95.2	4.0
1	25	160	57	34.9	34.9	35	34.9	3	4	1	7/8	108	5.4
1 1/4	32	185	73	43.7	43.7	38.1	43.7	5	4	1 1/8	1	130.2	8.1
1 1/2	40	205	79	50	50	44.5	50	6	4	1 1/4	1 1/8	146	10.8
2	50	235	95	62.5	62.5	50.9	62.5	8	8	1 1/8	1	171.4	18.9
2 1/2	65	265	114	75.4	75.4	57.2	75.4	8	8	1 1/4	1 1/8	196.8	24.8
3	80	305	133	91.4	91.4	66.7	91.4	10	8	1 3/8	1 1/4	228.6	40.8
4	100	355	165	116.8	116.8	76.2	116.8	11	8	1 5/8	1 1/2	273	61.6
5	125	420	203	144.4	144.4	92.1	144.4	11	8	1 7/8	1 3/4	323.8	102
6	150	485	235	171.4	171.4	108	171.4	13	8	2 1/8	2	368.3	160
8	200	550	305	222.2	222.2	127	222.2	13	12	2 1/8	2	438.2	239
10	250	675	375	277.4	277.4	165.1	277.4	13	12	2 5/8	2 1/2	539.8	459
12	300	760	441	328.2	328.2	184.2	328.2	13	12	2 7/8	2 3/4	619.1	540

Using Inconel 625 density (8.44 g/cm³), theoretical weights for backing flanges (RF facing) are:

NPS	Class 150 (kg)	Class 300 (kg)	Class 600 (kg)	Class 900 (kg)	Class 1500 (kg)	Class 2500 (kg)
2	2.1	3.6	3.6	6.4	6.4	10.2
4	7.2	13.4	13.4	25.8	25.8	45.6
6	17.3	33.5	33.5	64.1	64.1	113
8	32.5	64.8	64.8	131	131	233
12	84.5	176	176	382	382	688
24	572	1,235.00	1,235.00	2,940.00	2,940.00	5,520.00

The use of Inconel 625 lap joint flanges is an investment in system longevity. By following the ASME B16.5 specifications provided above, engineers can ensure that their piping assemblies are robust, maintainable, and compliant with international safety standards.

Genuine Manufacturing: In-house forging, no subcontracting.

Expertise: Years of alloy processing for optimal fatigue resistance.

Quality Control: ISO 9001; full documentation, NDT included.

Superior to Alternatives: Outperforms 316SS in chloride stress cracking.

Fast Turnaround: Stock for NPS ½"–6" Classes 150/300; custom in 4–6 weeks.

For quotations, contact our team.