Class 2500 Spectacle Blind Figure 8 Flanges

• Customization: Available
• Standard: ANSI, DIN, GB, JIS, GOST, BSW
• Type: Spectacle Blind Flange
• Model NO.: 1/2" - 12"
• Structure: Flanges
• Connection: Flanged
• Sealing Surface: RF
• Manufacturing Way: Forging
• Certificate: ISO9001
• Pressure: 150# 300# 400# 600# 900# 1500# 2500#
• Usage: Suitable for Water, Oil and Gas Industrial
• Connection Endstsocket Weld or Threaded: NPT, Bsp, BSPT etc
• Factory: Over 25 Years Experience
• Transport Package: Customized
• Specification: 1/2"-12"
• Trademark: GUCHENG
• Origin: Dingxiang
• HS Code: 73079100
• Production Capacity: 50000 Pieces/Year

Product Description

FORGING FLANGE -- Class 2500 Spectacle Blind Flange

Spectacle Blind Flange resembles like a pair of glasses; two metal discs are joined together by a section of metal to form the flange. These flanges are also called as 'figure8' flanges. The primary role of Spectacle Blind Flange is to curb any leakages from the pipeline when it is under maintenance. These Flanges are pressure-retaining plates used in high-pressure piping networks.

Our ASME B16.5 Spectacle Blind Flanges can be easily rotated to open and close the flow from pipes. They are used in applications that operate at sub-zero temperatures, and are volatile and toxic.

Standard Specification For Spectacle Blind Flanges

Dimensions: ANSI B16.5, ANSI B16.47 Series A & B, MSS SP44, ASA, API-605, AWWA, Custom Drawings
Size: 1/2" (15 NB) to 48" (1200NB)
Class: 150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS, DIN Standard ND-6,10, 16, 25, 40 Etc.
BS: BS4504 , BS4504, BS1560, BS10
Flange Face Type: Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)
Material: Stainless Steel, Carbon Steel, Low Temperature Carbon Steel, Alloy Steel, Etc.
Surface treatment: Anti-rust oil, transparent/yellow/black, Anti-rust paint, Zinc, Hot dipped galvanized
Usage: Oil field, Offshore, Water system, Shipbuilding, Natural gas, Electric power, Pipe projects,etc. 

Size in In.	Size in mm	Internal Diameter	Outer Diameter	Center to Center	Thickness	Web Width	Web Thickness	Hole Dia
1/2	15	16	67	90	9.7	38	5	22.225
3/4	20	21	73	95	9.7	41	5	22.225
1	25	27	83	110	9.7	64	5	25.4
1 1/4	32	35	102	130	12.7	64	7	28.575
1 1/2	40	41	114	145	15.7	70	8	31.75
2	50	53	143	170	15.7	70	8	28.575
2 1/2	65	63	165	195	19.1	76	10	31.75
3	80	78	194	230	22.4	76	12	34.925
4	100	102	232	275	28.4	89	22	41.275
5	130	128	276	325	35.1	89	27	47.625
6	150	154	314	370	41.1	89	31	53.975
8	200	198	384	440	53.8	102	41	53.975
10	250	248	473	540	66.5	114	50	66.675
12	300	289	546	620	79.2	114	60	73.025

ANSI B16.5 FORGED FLANGES TOLERANCE

THREAD,SOCKET-WELDING,                                                          SLIP-ON,LAP JOINT AND BLIND.			WELDING NECK
Outside Diameter	When O.D.is 24"or less	±1/16"(1.6mm)	Outside Diameter	When O.D.is 24"or less	±1/16"(1.6mm)*
	When O.D.is Over  24"	±1/8"(3.2mm)*		When O.D.is Over  24"	±18"(3.2mm)
Inside Diameter	Threaded	Within limits on boring gauge	Inside Diameter	10"and Smaller	±1/32"(0.8mm)
				20"thru 18"	±1/16"(1.6mm)
	Socket-Welding Slip-on and Lap joint	10"&Smaller +1/32"(0.8mm).0" 12"&Larger +1/16"(1.6mm).O"		20"and Larger	+1/8"(3.2mm) -1/16"(1.6mm)
Outside Diameter of Hub	5"and Smaller	+3/32"(2.4mm) -1/32"(0.8mm)	Diameter of Hub at Base	When Hub Base is 24"or Smaller	±1/16"(1.6mm)*
	6"and Larger	+5/32"(4.0mm) -1/32"(0.8mm)		When Hub Base is Over  24"	±1/8"(3.2mm)*
Diameter of Contact Face	1/16"Raised Face	±1/32"(0.8mm)	Diameter of Contact Face	116"Raised Face	±1/32"(0.8mm)
	1/4"Raised Face Tongue & Groove Male,Female	±1/64"(0.4mm)		14"Raised Face Tongue &Groove Male,Female	±1/64"(0.4mm)
Diameter of Counterbore	Same as for Inside Diameter		Diameter of Hub at Point of Welding	5"and Smaller	+3/32"(2.4mm)* -1/32"(0.8mm)
				6"and Larger	+5/32"(4.0mm) -1/32"(0.8mm)
Drilling	Bolt Circle	±1/16"(1.6mm)	Drilling	Bolt Circle	±1/16"(1.6mm)
	Bolt Hole Spacing	±1/32"(0.8mm)		Bolt Hole Spacing	±1/32"(0.8mm)
	Eccentricity of Bolt Circle with Respect to Facing	21/2"Smaller 1/32"(0.8mm)Max. 3"&Larger 1/16"(1.6mm)Max		Eccentricity of Bolt Circle with Respect to Facing	21/2"Smaller 1/32"(0.8mm)Max. 3"&Larger 1/16"(1.6mm)Max.
	Eccentricity of Bolt Circle with Respect to Bore	1/32"(0.8mm)Max.*		Eccentricity of Bolt Circle with Respect to Bore	1/32"(0.8mm)Max.*
	Eccentricity of Facing with Respect to Bore	1/32"(0.8mm)Max.*		Eccentricity of Facing with Respect to Bore	1/32"(0.8mm)Max.*
Thickness	18"and Smaller	+1/8"(3.2mm).0^	Thickness	18"and Smaller	+1/8"(3.2mm),0"
	20"and Larger	+3/16"(4.8mm).04		20"and Larger	+3/16"(4.8mm).O
Length Thru Hub	10"and Smaller	±1/16"(1.6mm)	Length Thru Hub	10"and Smaller	±1/16"(1.6mm)
	12"and Larger	±1/8"(3.2mm)		12"and Larger	±1/8"(3.2mm)

Notes:
This tolerance is not covered in ANSI B16.5, but maker's option.

STANDARD FINISHES for Face of Flange (ANSI  B16.5)
STOCK FINISH:
The most widely used gasket finish.because practically is suitable for all ordinary service conditions. This is a continuous spiral groove. Flanges size 12" (304.8mm)and smaller are produced with a 1/16" round-nosed tool at a feed of 1/32" per revolution. For sizes 14" (355.6mm)and larger. the finish is made with a 1/8" round-nosed tool at a feed of 3/64" per revolution.
SPIRAL SERRATED OR PHONOGRAPHIC:
This finish is produced by using a 90°round-nosed tool.
CONCENTRIC SERRATED:
This finish is produced by using a 90°round-nosed tool.
SMOOTH  FINISH:
The cutting tool employed shall have an approximate 0.06"radius.
The resultant surface finish shall have a 125μ inch to 250μ inch(ANSI B16.5 para 6.4;4.1)
1. RAISED FACE AND LARGE MALE AND FEMALE
    A serrated-concentric or serrated-spiral finish with 34 to 64 grooves per inch is used.
    The cutting tool employed has an approximate 0.06 in.radius.The resultant surface finish shall have a 125μ inch(3.2m)to 500μ inch(12.5μm) approximate roughness.
2. TONGUE AND GROOVE AND SMALL MALE AND FEMALE
    The gasket contact surface does not exceed 125μ in. (3.2μm)roughness
3. RING JOINT
    The inside wall surface of the gasket groove does not exceed 63μin.(1.6μm)roughness,
4. BLIND
    Blind flanges need not be faced in the center if, when this center part is raised, its diameter is at least 1 in. smaller than the inside diameter of the corresponding pressure class fittings. When the center part is depressed, its diameter is not greater than the inside diameter of the corresponding pressure class fittings. Machining of the depressed center is not required.

The manufacturing process of forged flanges begins with the selection of high-quality steel, which is heated and shaped under high pressure in forging dies to enhance its strength and durability. After forging, the flanges are trimmed, heat-treated to relieve internal stresses, and precisely machined to meet the required dimensions. They undergo rigorous inspection and testing for quality assurance, followed by surface treatments for enhanced corrosion resistance. This process results in flanges that are strong, reliable, and suitable for demanding industrial environments.

Company Profile

Dingxiang Country Gu Cheng Forging Company Ltd.  is a leading manufacturer in Dingxiang County, Shanxi Province, known as the "Forging Capital of China." Established with a deep-rooted history in forging, we specialize in producing high-quality flanges and forged components for a wide range of industrial applications. Our extensive product line includes ANSI, DIN, JIS, and EN standard flanges and customized forged parts designed to meet specific customer requirements.

Gu Cheng Forging with over 30 years of experience in producing high-quality forged flanges. Including Weld Neck Flange (WN), Slip-On Flange (SO), Blind Flange (BL), Socket Weld Flange (SW), Lap Joint Flange, Plate Flange, and Customized forged flange.

At Gu Cheng Forging, we serve a global market, providing flanges and forged components for industries such as oil and gas, chemical processing, power generation, shipbuilding, and more. We pride ourselves on our ability to deliver tailored solutions, meeting the highest standard of safety, performance, and efficiency.

As a factory, we can tailor flanges based on your specific requirements for size, material, pressure rating, and surface treatment (galvanization, black paint, etc.). By preventing rust and deterioration, the coating enhances the flange's performance, offering long-term resilience and reducing maintenance needs over time.

Dingxiang Country Gu Cheng Forging Company Ltd,  strives to be a trusted partner for all your forging needs, ensuring long-term cooperation and mutual success.

Q1: Are you a manufacturer or a trading company?
A1: We are a professional manufacturer with over 30 years of experience in forging flanges. Our factory is located in Dingxiang, China, known as the "Forging Capital." We produce high-quality, customized forged flanges, offering factory-direct pricing and ensuring top-notch quality.

Q2: What types of flanges do you produce?
A2: We manufacture a wide range of forged flanges, including:

• Weld Neck Flange (WN)
• Slip-On Flange (SO)
• Blind Flange (BL)
• Socket Weld Flange (SW)
• Threaded Flange (TH)
• Lap Joint Flange
• Plate Flange

All our flanges comply with international standards such as ASME, DIN, JIS, and BS.

Q3: What materials do you use?
A3: We offer flanges in a variety of materials, including:

• Carbon Steel
• Stainless Steel
• Alloy Steel

Each material is sourced from certified suppliers, ensuring durability and performance in diverse industrial applications.

Q4: Can you provide customized flanges?
A4: Absolutely! As a factory, we specialize in customization. We can tailor flanges based on your specific requirements for size, material, pressure rating, and surface treatment (galvanization, black paint, etc.).

Q5: How do you ensure the quality of your products?
A5: Quality is our top priority. Every flange undergoes a strict inspection process, including:

• Material analysis
• Dimensional checks
• Pressure testing
• Surface treatment inspections

Our CNC machining ensures precise dimensions, and we adhere to strict international standards throughout the manufacturing process.