Complete Lap Joint Flange Solutions Manufacturer for Various Pipeline Systems

• Customization: Available
• Standard: ANSI, DIN, GB, JIS, GOST, BSW
• Type: Lap Joint
• Model NO.: 1/2"-24"
• Material: Stainless Steel
• Structure: Flanges
• Connection: Flanged
• Sealing Surface: RJ
• 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 30 Years Experience
• Transport Package: Customized
• Specification: 1/2"-24"
• Trademark: GUCHENG
• Origin: Dingxiang
• HS Code: 73079100
• Production Capacity: 50000 Pieces/Year

Product Description

ANSI B16.5 FORGING FLANGE -- LAP JOINT FLANGE Class 300

Lap joint flange is a type of flange that is designed for use with a stub end, allowing for easy alignment and disassembly in piping systems. The flange features a flat face that overlaps the stub end, enabling it to be easily rotated around the pipe, simplifying installation and maintenance, especially in applications requiring frequent access.

Lap joint flanges conforming to ASME/ANSI B16.5 in Class 150 through Class 2500 covering a comprehensive range of steel and alloy steel materials. Attachment of the lap joint flange to the piping system requires a lap-joint stub end. The stub end can be viewed as a length of pipe sleeve with one end butt welded and the other end flared at right angle to the pipe axis. The lap-joint flange and stub end compose a two-piece composite lap joint connection.

In this lapped connection, prior to the "pipe sleeve" being welded to the adjoining pipe, the loose-type lap joint flange slip over the straight length of the pipe sleeve and abuts against the back face of the stub end or its "flared shoulder". It is free to spin the flange for proper alignment of bolt holes, which is used to bolt the joint together subsequently. The lap joint flange is also known as a lapped "backing flange" and the flared end is also called as "lap" of the stub end.

Product Parameters

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

 

Nominal Pipe Size	Outside Diam.	Diam. at Base of Hub	O.D.of Raised Face	Thickness	BORE				LENGTH   THRU  HUB			Diam.of Hub at Bevel	Radius of Fillet	Thread Length
					Welding Neck Socket Welding	Slip-on Socket Welding	Lap Joint	Counter Bore MIn. Threaded Min.	Welding Neck	Slip-on Threaded Socket Welding	Lap Joint
	D	X	G	t	B1	B2	B3	B	T1	T2	T3	A	R	Q
1/2	95	38.1	35.1	14.2	15.7	22.4	22.9	23.6	52.3	22.4	22.4	21.3	3.0	15.7
3/4	117	47.8	42.9	15.7	20.8	27.7	28.2	29.0	57.2	25.4	25.4	26.7	3.0	15.7
1	124	53.8	50.8	17.5	26.7	34.5	35.1	35.8	62.0	26.9	26.9	33.5	3.0	17.5
1 1/4	133	63.5	63.5	19.1	35.1	43.2	43.7	44.5	65.0	26.9	26.9	42.2	4.8	20.6
1 1/2	155	69.9	73.2	20.6	40.9	49.5	50.0	50.5	68.3	30.2	30.2	48.3	6.4	22.4
2	165	84.1	91.9	22.4	52.6	62.0	62.5	63.5	69.9	33.3	33.3	60.5	7.9	28.4
2 1/2	191	100.1	104.6	25.4	62.7	74.7	75.4	76.2	76.2	38.1	38.1	73.2	7.9	31.8
3	210	117.3	127.0	28.4	78.0	90.7	91.4	92.2	79.2	42.9	42.9	88.9	9.7	31.8
3 1/2	229	133.4	139.7	30.2	90.2	103.4	104.1	104.9	81.0	44.5	44.5	101.6	9.7	36.6
4	254	146.1	157.2	31.8	102.4	116.1	116.8	117.6	85.9	47.8	47.8	114.3	11.2	36.6
5	279	177.8	185.7	35.1	128.3	143.8	144.5	144.5	98.6	50.8	50.8	141.2	11.2	42.9
6	318	206.2	215.9	36.6	154.2	170.7	171.5	171.5	98.6	52.3	52.3	168.4	12.7	46.0
8	381	260.4	269.7	41.1	202.7	221.5	222.3	222.3	111.3	62.0	62.0	219.2	12.7	50.8
10	445	320.5	323.9	47.8	254.5	276.4	277.4	276.4	117.3	66.5	95.3	273.1	12.7	55.6
12	521	374.7	381.0	50.8	304.8	327.2	328.2	328.7	130.0	73.2	101.6	323.9	12.7	605
14	584	425.5	412.8	53.8	336.6	359.2	360.2	360.4	142.7	76.2	111.3	355.6	12.7	63.5
16	648	482.6	469.9	57.2	387.4	410.5	411.2	411.2	146.1	82.6	120.7	406.4	12.7	68.3
18	711	533.4	533.4	60.5	438.2	461.8	462.3	462.0	158.8	88.9	130.0	457.2	12.7	69.9
20	775	587.2	584.2	63.5	489.0	513.1	5,144	512.8	162.1	95.3	139.7	508.0	12.7	73.2
24	914	701.5	692.2	69.9	590.6	616.0	616.0	614.4	168.1	106.4	152.4	609.6	12.7	82.6

 

Nominal Pipe Sze	Depth of Socket	DRILLING			BOLTING				APPROXIMATE    WEIGHT
		Bolt Circle Diam	Number of Holes	Diam. of Holes	Diam. of Bolt (inch)	Machine Bolt Length	Stud Bolt Length		Welding Neck		Slip-on   and Threaded		Lap Joint		Blind		Socket Welding
						Raised Face	Raised Face	Ring Joint
	Y								Kg	Ib	Kg	Ib	Kg	Ib	Kg	Ib	Kg	Ib
1/2	9.7	66.5	4	15.7	1/2	57.2	63.5	76.2	0.78	1.70	0.62	1.40	0.61	1.30	0.62	1.40	0.62	1.40
3/4	11.2	82.6	4	19.1	5/8	63.5	76.2	88.9	1.34	3.00	1.15	2.50	1.15	2.50	1.16	2.50	1.19	2.60
1	12.7	88.9	4	19.1	5/8	63.5	76.2	88.9	1.64	3.60	1.39	3.10	1.38	3.00	1.42	3.00	1.44	3.2
1 1/4	14.2	98.6	4	19.1	5/8	69.9	82.6	95.3	2.06	4.50	1.67	3.70	1.66	3.70	1.79	3.90	1.73	3.80
1 1/2	15.7	114.3	4	22.4	3/4	76.2	88.9	101.6	3.06	6.70	2.53	5.60	2.52	5.60	2.68	5.90	2.62	5.80
2	17.5	127.0	8	19.1	5/8	76.2	88.9	101.6	3.40	7.50	2.80	6.20	2.79	6.20	3.09	6.80	2.94	6.50
2 1/2	19.1	149.4	8	22.4	3/4	82.6	101.6	114.3	5.31	11.70	4.25	9.40	4.22	9.30	4.75	10.50	4.49	9.90
3	20.6	168.1	8	22.4	3/4	88.9	108.0	120.7	7.32	16.10	5.81	12.80	5.78	12.70	6.79	14.90	6.20	13.70
3 1/2	22.4	184.2	8	22.4	3/4	95.3	108.0	127.0	8.17	18.00	7.72	17.00	7.72	17.00	9.53	21.00
4	23.9	200.2	8	22.4	3/4	95.3	114.3	127.0	11.30	24.90	10.13	22.30	10.07	22.20	12.00	26.50
5	23.9	235.0	8	22.4	3/4	108.0	120.7	133.4	15.12	33.30	12.58	27.70	12.52	27.60	15.96	35.20
6	26.9	269.7	12	22.4	3/4	108.0	120.7	139.7	19.68	43.40	16.04	35.40	15.95	35.20	21.20	46.70
8	31.8	330.2	12	25.4	7/8	120.7	139.7	152.4	30.48	67.20	24.50	54.00	24.37	53.70	34.60	76.30
10	33.3	387.4	16	28.4	1	139.7	158.8	171.5	43.74	96.40	34.16	75.30	39.92	88.00	55.34	122.00
12	39.6	450.9	16	31.8	1 1/8	146.1	171.5	184.2	64.41	142.00	51.26	113.00	58.70	129.40	78.90	174.00
14	41.4	514.4	20	31.8	1 1/8	158.8	177.8	190.5	88.30	194.70	72.12	159.00	83.46	184.00	107.05	236.00
16	44.5	571.5	20	35.1	1 1/4	165.1	190.5	203.2	112.94	249.00	90.40	199.30	106.14	234.00	139.25	307.00
18	49.3	628.7	24	35.1	1 1/4	171.5	196.9	209.6	138.34	305.00	109.00	240.30	133.95	295.30	176.90	396.00
20	54.1	685.8	24	35.1	1 1/4	184.2	203.2	222.3	167.37	369.00	136.00	300.00	157.65	347.60	223.17	492.00
24	63.5	812.8	24	41.1	1 1/2	203.2	228.6	254.0	235.41	519.00	204.00	449.70	240.40	530.00	342.00	754.00

Notes:
(1) For the 'Bore'(B1) other than Standard Wall Thickness, refer to the bellow.
(2) Class 300 flanges except the Lap Joint will be furnished with 0.06" (1.6mm) raised face, which is included in Thickness'(t) and 'Length through Hub'(T1), (T2).
(3) For Slip-on, Threaded, Socket Welding, and Lap Joint Flanges, the hubs can be shaped either vertically from base to top or tapered within the limits of 7 degrees.
(4) Blind Flanges may be made with the same hub as that used for Slip-on Flanges or without a hub.
(5) Thegasket surface and backside(bearing suface for bolting)are made parallel within 1 degree.To accomplish parallelism, spot-facing is carried out according to MSS SP-9, without reducing thickness(t).
(6) Depth of Socket (Y) is covered by ANSI B16.5 only in sizes through 3 inch, over 3 inch is at the manufacturer's option.

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.