Stainless Steel 316L Blind Flanges

zhao77jie — Tue, 16 Sep 2025 02:00:00 +0000

In early September 2025, we received another order from a long-term customer in the UK. This was their second order from us, again for Stainless Steel 316L blind flanges. Their requirements were very specific: not only did they prioritize on-time delivery, but they also placed particular emphasis on the flange’s appearance and the accompanying EN 10204 3.1 Material Test Certificate (MTC).

After receiving the order, we immediately arranged a production schedule. During the production process, we rigorously implement dimensional inspections, outer diameter measurements, and bolt hole distribution checks to ensure that every flange complies with ASME/EN standards.

Because of the customer’s high expectations for product appearance, we pay particular attention to the surface treatment of the flanges. All flanges undergo a visual inspection before shipment to ensure a smooth, flat surface, free of scratches or burrs. Furthermore, each shipment includes a 3.1 MTC, which fully documents the material’s chemical composition and mechanical properties, ensuring traceability and reliability. For packaging, we use plastic film wrapping and moisture-proof wooden crates to ensure safety during transportation while enhancing the overall aesthetics.

If you’re looking for a reliable stainless steel flange manufacturer, please feel free to contact us.

Outside Diameter Inspection

Use a caliper or specialized measuring tool to measure the flange’s outside diameter to ensure it conforms to the standard size.

Thickness Inspection

Measure the overall flange thickness and the sealing surface thickness to prevent deviations that could lead to insufficient strength or seal failure.

Bolt Hole Inspection

Check whether the number, diameter, and distribution of bolt holes meet standards.

Measure the bolt circle diameter (BCD).

Facing Inspection

According to customer requirements, inspect the sealing surface type (RF, FF, RTJ) and measure the roughness and surface flatness.

Marking Inspection

Confirm that the flange surface markings (material, specification, pressure rating, standard number, heat number) are complete and legible for traceability.

Other Visual Inspections

Inspect the flange surface for defects such as cracks, burrs, scratches, and rust.

Sealing Face	RF, FF, FTJ
Size Range	1/2” – 48” / DN15 – DN1200
Pressure Rating	Class 150, 300, 600, 900, 1500, 2500lb
Standard	ASME / ANSI 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

ASTM A182 F316L Flange Chemical Composition

CHEMICAL	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo	N
ASTM A182 F316	MIN						10.0	16.0	2.00
ASTM A182 F316	MAX	0.08	2.00	0.045	0.030	1.00	14.0	18.0	3.00	0.10
ASTM A182 F316L	MIN						10.00	16.0	2.00
ASTM A182 F316L	MAX	0.03	2.00	0.045	0.030	1.00	15.00	18.0	3.00	0.10

ASTM A182 F316L Flange Mechanical Property

MATERIAL	ASTM A182 F316	ASTM A182 F316L
T.S (MPA)	515 min	485 min
Y.S (MPA)	205 min	170 min
EL %	30 min	30 min
R/A %	50 min	50 min

Nominal Pipe Size		A	C	G	H	I	J	Weight
Nominal Pipe Size	mm	mm	mm	mm	Number of Holes	mm	mm	kg/piece
1/2	21.3	95.2	14.2	35.1	4	15.7	66.55	0.64
3/4	26.7	117.3	15.7	42.9	4	19	82.5	1.11
1	33.4	123.9	17.5	50.8	4	19	88.9	1.39
11/4	42.2	133.3	19	63.5	4	19	98.5	1.79
11/2	48.3	155.4	20.6	73.15	4	22.3	114.3	2.66
2	60.3	165. 1	22.3	91.9	8	19. 10	127	3.18
21/2	73.0	190.5	25.4	104.6	8	22.3	1.493	4.85
3	88.9	209.5	28.4	127	8	22.3	168.1	6.81
31/2	101.6	228.6	30.2	139.7	8	22.3	184.1	8.71
4	114.3	254	31.7	157.2	8	22.3	200.1	11.5
5	141.3	279.4	35	185.7	8	22.3	234.9	15.6
6	168.3	317.5	36.5	215.9	12	22.3	269.7	20.9
8	219. 1	381	1.620 41.10	269.7	12	25.4	330.2	34.3
10	273.0	444.5	47.7	323.9	16	28.4	387.3	53.3
12	323.8	520.7	50.8	381	16	31.7	450.8	78.8
14	355.6	584.2	53.8	412.8	20	31.7	514.3	105
16	406.4	647.7	57.15	469.9	20	35	571.5	137
18	457.2	711.2	60.45	533.4	24	35	628.6	175
20	508.0	774.7	63.5	584.2	24	35	685.8	221
24	609.6	914.4	69.85	692.2	24	41. 10	812.8	339

Class 300 Stainless Steel Flange Weight

Pressure	Size	SO	TH	SW	LAPJ	BL	WN
300LB	1/2	0.68	0.68	1.36	0.68	0.91	0.91
	3/4	1.14	1.14	1.36	1.14	1.16	1.36
	1	1.36	1.36	1.36	1.36	1.82	1.82
	1 1/4	2.04	2.04	1.82	2.04	2.72	2.27
	1 1/2	2.95	2.95	2.72	2.95	3.18	3.18
	2	3.18	3.18	3.18	3.18	3.63	3.63
	2 1/2	4.54	4.54	4.54	4.54	5.45	5.45
	3	5.90	6.36	5.90	6.58	7.26	8.17
	3 1/2	7.20	7.26	7.72	7.26	9.53	9.10
	4	10.67	10.90	9.99	10.90	12.71	12.03
	5	13.17	14.07	–	11.80	16.80	16.34
	6	16.34	16.34	–	17.25	21.79	20.43
	8	25.42	25.42	–	24.97	35.87	31.33
	10	34.96	36.32	–	39.95	55.39	45.40
	12	51.30	49.94	–	63.11	83.48	64.47
	14	72.19	74.46	–	83.54	109.41	93.52
	16	95.34	99.88	–	106.24	143.01	113.05
	18	114.86	127.12	–	138.40	187.96	138.92
	20	139.38	147.55	–	170.25	233.81	167.53
	24	222.46	222.46	–	240.62	363.20	235.63

Different Face Types

Similar to other flanges, blind flanges can have different face types to match the mating flange and gasket:

Raised Face (RF): The most common type, featuring a raised ring around the bore to concentrate sealing pressure.

Flat Face (FF): Has a flat sealing surface, typically used with flat face mating flanges, often in low-pressure applications or with fragile flanges.

Ring Joint (RTJ): Features a groove to accommodate a metal ring gasket, designed for high-pressure and high-temperature service.

Applications

Offshore and Marine Piping

Chemical Processing Plants

Water Treatment Systems

Pharmaceutical and Food Processing

Heat Exchangers, Pumps, and Valve Ends

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