ASME B16.5 CLASS 300 Flange

ASME B16.5 is a standard developed by the American Society of Mechanical Engineers for pipe flanges and flange connections. This standard provides detailed specifications for flanges of various sizes, pressure levels, materials, and surface types to meet the needs of various industrial applications. ASME B16.5 Class 300 flange, as an important type, is widely used in industries such as petroleum, chemical, natural gas, power, pharmaceuticals, and food.

Types & Material

ASME B16.5 Class 300 flanges have a variety of types and can be classified according to the connection method:welding neck flange,slip on flange,socket welding flange,threaded flange,lap joint flange,blind flange。

According to material:carbon steel flange,alloy steel flange,stainless steel flange,duplex stainless steel flange etc.

Sealing Face	RF, FF, FTJ
Size Range	1/2" - 48"/ DN15 - DN1200
Pressure Rating	Class 150, 300, 600, 900, 1500, 2500lb
Standard	ASME B16.5, ASME B16.47 Series A/B
Carbon Steel	ASTM A105 / A105N
Low Temp Carbon Steel	ASTM A350 LF2/LF3
Pipeline Steel	ASTM A694 F42 / 46 / 56 / 60 / 65
Alloy Steel	ASTM A182 F11 / 12 / 5 / 9 / 91 / 92
Stainless Steel	ASTM A182 F304/304L/304H, 316/316L, 310S, 317,347,904L
Duplex Stainless Steel	ASTM A182 F51, F53, F44

Chemical Composition

Carbon steel

CHEMICAL	LIMITS	C	Mn	P	S	Si	Cu	Ni	Cr	Mo	V
ASTM A105	MIN		0.60			0.10
	MAX	0.35	1.05	0.035	0.040	0.35	0.40	0.40	0.30	0.12	0.08

Stainless Steel

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 F316	MIN						10.0	16.0	2.00
	MAX	0.08	2.00	0.045	0.030	1.00	14.0	18.0	3.00	0.01

Alloy Steel

CHEMICAL	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo
ASTM A182 F5	MIN		0.30					4.00	0.44
	MAX	0.15	0.60	0.030	0.030	0.50	0.50	6.00	0.65
ASTM A182 F9	MIN		0.30			0.50		8.00	0.90
	MAX	0.15	0.60	0.030	0.030	1.00		10.00	1.10
ASTM A182 F11 CL1	MIN	0.05	0.30			0.50		1.00	0.44
	MAX	0.15	0.60	0.03	0.03	1.00		1.50	0.65

Duplex Stainless Steel

CHEMICAL	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo	N
ASTM A182 F51	MIN						4.50	21.00	2.50	0.08
	MAX	0.03	2.00	0.030	0.020	1.00	6.50	23.00	3.50	0.20

Mechanical Properties

Carbon steel

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %	HARDNESS
ASTM A105	485 min	250 min	22 min	30 min	197 max

Stainless Steel

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %
ASTM A182 F304	515 min	205 min	30 min	50 min
ASTM A182 F316	515 min	205 min	30 min	50 min

Alloy Steel

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %	HARDNESS
ASTM A182 F5	485 min	275 min	20 min	35 min	143-217
ASTM A182 F9	585 min	380 min	20 min	40 min	179-217
ASTM A182 F11 CL1	415 min	205 min	20 min	45 min	121-174

Duplex Stainless Steel

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %
ASTM A182 F51	620 min	450 min	25 min	45 min

Dimension of ASME B16.5 CLASS 300 Flange 

1	2	3	4	5		6		7	8	9	10		11	12	13	14	15	16
Nominal Pipe Size NPS	Outside Diamter        of Flange,         O	Minimum Thickness of Flange, tf (2)–(4)	Minimum Thickness Lap Joint, tf	Diameter of Hub, X		Hub Diameter Beginning of Chamfer Welding Neck, Ah  (4)		Length Through Hub			Minimum Thread Length Threaded, T (5)		Bore			Corner Radius of Bore of Lapped Flange and Pipe, r	Minimum Counter-        bore Threaded      Flange,           Q	Depth of Socket, D
								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 (6)
1/2	95	12.7	14.2	38		21.3		21	22	51	16		22.4	22.9	15.7	3	23.6	10
3/4	117	14.2	15.7	48		26.7		24	25	56	16		27.7	28.2	20.8	3	29.0	11
1	124	15.7	17.5	54		33.5		25	27	60	18		34.5	35.1	26.7	3	35.8	13
1 1/4	133	17.5	19.0	64		42.2		25	27	64	21		43.2	43.7	35.1	5	44.4	14
1 1/2	155	19.0	20.6	70		48.3		29	30	67	22		49.5	50.0	40.9	6	50.3	16

Table 11 Dimensions of Class 300 Flanges (Cont’d)
1	2	3	4	5	6		7	8	9	10	11	12	13	14	15	16
Nominal Pipe Size NPS	Outside Diamter of Flange, O	Minimum Thickness of Flange, tf (2)–(4)	Minimum Thickness Lap Joint, tf	Diameter of Hub, X	Hub    Diameter Beginning            of     Chamfer     Welding Neck, Ah  (4)		Length Through Hub			Minimum Thread Length Threaded, T (5)	Bore			Corner Radius of Bore of Lapped Flange and Pipe, r	Minimum Counter-        bore Threaded      Flange,           Q	Depth of Socket, D
							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 (6)
2	165	20.6	22.4	84	60.5		32	33	68	28	62.0	62.5	52.6	8	63.5	17
21∕2	190	23.9	25.4	100	73.2		37	38	75	32	74.7	75.4	62.7	8	76.2	19
3	210	26.9	28.4	117	88.9		41	43	78	32	90.7	91.4	78.0	10	92.2	21
31∕2	229	28.4	30.2	133	101.6		43	44	80	37	103.4	104.1	90.2	10	104.9	…
4	254	30.2	31.8	146	114.3		46	48	84	37	116.1	116.8	102.4	11	117.6	…
5	279	33.3	35.1	178	141.2		49	51	97	43	143.8	144.5	128.3	11	144.5	…
6	318	35.1	36.6	206	168.4		51	52	97	46	170.7	171.4	154.2	13	171.4	…
8	381	39.6	41.1	260	219.2		60	62	110	51	221.5	222.2	202.7	13	222.2	…
10	444	46.0	47.8	321	273.0		65	95	116	56	276.4	277.4	254.5	13	276.4	…
12	521	49.3	50.8	375	323.8		72	102	129	60	327.2	328.2	304.8	13	328.7	…
14	584	52.3	53.8	425	355.6		75	111	141	64	359.2	360.2	(7)	13	360.4	…
16	648	55.6	57.2	483	406.4		81	121	145	68	410.5	411.2	(7)	13	411.2	…
18	711	58.7	60.5	533	457.2		87	130	157	70	461.8	462.3	(7)	13	462.0	…
20	775	62.0	63.5	587	508.0		94	140	161	73	513.1	514.4	(7)	13	512.8	…
22	838	65.0	66.5	641	558.8		100	145	164	…	564.4	565.2	(7)	13	…	…
24	914	68.3	68.8	702	609.6		105	152	167	83	616.0	616.0	(7)	13	614.4	…

GENERAL NOTES:

(a)  Dimensions are in millimeters.

(b)  For tolerances, see section 7.

(c)  For facings, see para. 6.4.

(d)  For flange bolt holes, see para. 6.5 and Table 10.

(e)  For spot facing, see para. 6.6.

(f)   For reducing threaded and slip-on flanges, see Table 6.

(g)  Blind flanges may be made with or without hubs at the manufacturer’s option.

(h)  For reducing welding neck flanges, see para. 6.8.

NOTES:

(1)  This dimension is for the large end of the hub, which maybe straight or tapered. Tapershall not exceed 7 deg on threaded, slip-on, socket-welding, and lapped flanges. This dimension is defined

as the diameter at the intersection between the hub taper and back face of the flange.

(2)  These flanges maybe supplied with a flat face. The flat face maybe either the full tf dimension thickness plus 1.5 mm or the tf dimension thickness without the raised face height. See para. 6.3.2

for additional restrictions.

(3)  The flange dimensions illustrated are for regularly furnished 1.5-mm raised face (except lapped); for requirements of other facings, see Figure 6.

ASME B16.5 Class 300 flange is a common pipe fitting with the following characteristics:

1. Moderate pressure rating: Class 300 flanges are suitable for medium pressure rating pipeline systems and typically can withstand working pressures of 150 to 300 psi (pounds per square inch).

2. Diversified materials and sealing surfaces: Class 300 flanges can be made of various materials, such as carbon steel, stainless steel, etc., to meet the needs of different media and environments. In addition, the flange also has various surface types, such as raised face (RF), concave face (FM), tenon face (M), and ring connection face (RJ), to meet various connection requirements.

3. Excellent sealing performance: Class 300 flanges focus on improving sealing performance during the design and manufacturing process. By adopting a reasonable sealing structure and high-quality sealing materials, it is ensured that the flange connection has good sealing performance and prevents medium leakage.

4. Easy to install and maintain: The Class 300 flange adopts standard dimensions and connection methods, making installation and maintenance simple and convenient. Meanwhile, the flange also has good interchangeability, reducing maintenance and replacement costs.

ASME B16.5 Class 300 flanges are widely used in industries such as petroleum, chemical, natural gas, electricity, pharmaceuticals, and food. In these fields, Class 300 flanges play an important connecting role, ensuring the safe and stable operation of pipeline systems.