Stainless steel 304 flanges play a crucial role in piping systems, providing a means for connecting pipes, valves, pumps, and other equipment. Stainless Steel Flanges are designed to withstand high-temperature and corrosive environments, making them suitable for applications in industries such as petrochemical, chemical processing, oil and gas, and power generation.

Specification of ASTM A182 Flange

Sealing Face	RF, FF, FTJ
Size Range	1/2″ – 24″ / DN15 – DN600
Pressure Rating	Class 150, 300, 600, 900, 1500, 2500lb
Standard	ANSI / ASME B16.5, EN1092-1
Flange Types	Welding Neck Flange, Slip On Flange, Socket Weld Flange, Lap Joint Flange, Threaded Flange, Blind Flange,
Stainless Steel	ASTM A182 F304/304L/304H, 316/316L, 310S, 317,347,904L

Chemical Composition for ASTM A182 F304 SS Flange

CHEMICAL	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo	N
ASTM A182 F304	MIN						8.0	18.0
	MAX	0.08	2.00	0.045	0.030	1.00	11.0	20.0		0.10
ASTM A182 F304H	MIN	0.04					8.00	18.00
	MAX	0.10	2.00	0.045	0.030	1.00	11.00	20.00
ASTM A182 F304L	MIN						8.00	18.00
	MAX	0.03	2.00	0.045	0.030	1.00	13.00	20.00		0.10

Stainless Steel 304 Flange Mechanical Properties

MATERIAL	ASTM A182 F304	ASTM A182 F304H	ASTM A182 F304L
T.S (MPA)	515 min	515 min	485 min
Y.S (MPA)	205 min	205 min	170 min
EL %	30 min	30 min	30 min
R/A %	50 min	50 min	50 min

Stainless Steel 304 Flange Physical Properties

Grade	Density(kg/m3)	Elastic Modulus (GPa)	Mean Coefficient of Thermal Expansion (μm/m/°C)			Thermal Conductivity (W/m.K)		Specific Heat 0-100°C(J/kg.K)	Electrical Resistivity (nΩ.m)
			0-100°C	0-315°C	0-538°C	at 100°C	at 500°C
304/L/H	8000	193	17.2	17.8	18.4	16.2	21.5	500	720

Stainless Steel 304 Flanges Equivalent

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
SS 304	1.4301	S30400	SUS 304	304S31	08Х18Н10	Z7CN18‐09	X5CrNi18-10

Stainless Steel 304 Types of Flanges

Weld Neck flange

The weld neck flange has a structure with a neck and a round tube transition, which can be butt weld to the pipe to form a firm pipe connection point.

Socket weld flange

 Socket Weld Flange designed in accordance with ASME B16.5 standards, is a high-integrity flange used for creating a secure pipe connection in high-pressure systems.

Threaded flange

The threaded flange uses a screw thread to connect the flange onto pipe. A male thread is cut onto a pipe end while a female thread is cut into the bore of the flange. The male threaded pipe is then screwed into the female threaded flange.

Lap joint flange

The main structural feature of the lap joint flange is the loose connection. It consists of a flange body, a flange nipple and connecting bolts. The flange body and the flange nipple are loose fitting, and this structure allows the pipeline to expand and contract freely within a certain range.

Blind flange

Blind flanges help to terminate the ends of piping systems. The main purpose of using blind flanges is to close off the unused portion of pipe or nozzle.

Slip on flange

Slip on flange is mainly used for low-pressure fluids that have minimal risk of leakage. Stainless Steel Slip On Flange is commonly used in water lines, low-pressure compressed airlines, etc.

Class 150 Stainless Steel Flange Dimension

Nominal Pipe Size, NPS	Outside Diameter of Flange, O	Minimum Thickness of  Flange, tf [Notes(2)-(4)]	Minimum Thickness Lap Joint, tf	Diameter of  Hub, X	Hub Diameter Beginning of Chamfer Welding Neck, Ah [Note (5)]	Length Through Hub			Minimum Thread Length Threaded, T [Note (6)]	Bore
						Threaded/ Slip-on/ Socket Welding,              Y	Lapped,           Y	Welding Neck, Y		Minimum Slip-on/ Socket      Welding,                 B	Minimum Lapped, B	Welding Neck/ Socket Welding, B [Note (7)]
1/2	90	9.6	11.2	30	21.3	14	16	46	16	22.2	22.9	15.8
3/4	100	11.2	12.7	38	26.7	14	16	51	16	27.7	28.2	20.9
1	110	12.7	14.3	49	33.4	16	17	54	17	34.5	34.9	26.6
1 1/4	115	14.3	15.9	59	42.2	19	21	56	21	43.2	43.7	35.1
1 1/2	125	15.9	17.5	65	48.3	21	22	60	22	49.5	50.0	40.9
2	150	17.5	19.1	78	60.3	24	25	62	25	61.9	62.5	52.5
2 1/2	180	20.7	22.3	90	73.0	27	29	68	29	74.6	75.4	62.7
3	190	22.3	23.9	108	88.9	29	30	68	30	90.7	91.4	77.9
3 1/2	215	22.3	23.9	122	101.6	30	32	70	32	103.4	104.1	90.1
4	230	22.3	23.9	135	114.3	32	33	75	33	116.1	116.8	102.3
5	255	22.3	23.9	164	141.3	35	36	87	36	143.8	144.4	128.2
6	280	23.9	25.4	192	168.3	38	40	87	40	170.7	171.4	154.1
8	345	27.0	28.6	246	219.1	43	44	100	44	221.5	222.2	202.7
10	405	28.6	30.2	305	273.0	48	49	100	49	276.2	277.4	254.6
12	485	30.2	31.8	365	323.8	54	56	113	56	327.0	328.2	304.8
14	535	33.4	35.0	400	355.6	56	79	125	57	359.2	360.2	Note(8)
16	595	35.0	36.6	457	406.4	62	87	125	64	410.5	411.2	Note(8)
18	635	38.1	39.7	505	457.0	67	97	138	68	461.8	462.3	Note(8)
20	700	41.3	42.9	559	508.0	71	103	143	73	513.1	514.4	Note(8)
24	815	46.1	47.7	663	610.0	81	111	151	83	616.0	616.0	Note(8)

A182 Gr.F304 Pressure-Temperature Ratings

Working Pressures by Classes,psig
Class
Temp.,F	150	300	400	600	900	1500	2500
-20 to 100	275	720	960	1440	2160	3600	6000
200	230	600	800	1200	1800	3000	5000
300	205	540	715	1075	1615	2690	4480
400	190	495	660	995	1490	2485	4140
500	170	465	620	930	1395	2330	3880
600	140	440	590	885	1325	2210	3.68
650	125	430	575	865	1295	2160	3600
700	110	420	565	845	1265	2110	3520
750	95	415	550	825	1240	2065	3440
800	80	405	540	810	1215	2030	3380
850	65	395	530	790	1190	1980	3300
900	50	390	520	780	1165	1945	3240
950	35	380	510	765	1.145	1910	3180
1000	20	355	470	710	1065	1770	2950
1050		325	435	650	975	1630	2715
1100		255	345	515	770	1285	2145
1150		205	275	410	615	1030	1715
1200		165	220	330	495	825	1370
1250		135	180	265	400	670	1115
1300		115	150	225	340	565	945
1350		95	125	185	280	465	770
1400		75	100	150	225	380	630
1450		60	80	115	175	290	485
1500		40	55	85	125	205	345

Advantages of Stainless Steel 304 Flanges

• Excellent Corrosion Resistance

Resistant to corrosion from water, steam, and acid-alkali solutions, suitable for a variety of mild to moderate corrosive environments.

• Good Mechanical Properties

High tensile strength and good toughness, suitable for welding and processing.

• High Temperature Oxidation Resistance

Can withstand temperatures up to 870°C, and up to 925°C for short periods.

• High cost-effectiveness

Offers superior performance at a cost significantly lower than high-nickel alloys and duplex steel flanges.

Application Areas

Chemical/petrochemical equipment

Food processing and brewing industry

Water supply and drainage systems

Pharmaceutical piping systems

Shipbuilding and marine engineering

Fire protection and HVAC systems