Stainless Steel Lap Joint Flange Manufacturer with Superior Corrosion Resistance

• Customization: Available
• Standard: ANSI, DIN, GB, JIS, GOST, BSW
• Type: Lap Joint
• Model NO.: 6"
• Material: Carbon 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

ASME/ANSI B16.5 FORGING FLANGE -- LAP JOINT FLANGE Class 900

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)

Threaded Flange (TH)	Lap Joint Flange (LJ)	Blind Flange (BL)

 

Nominal Pipe Size	Outside Diam.	Diam at Base of Hub	0.D.of Raised Face	Thickness	BORE					LENGTH  THRU  HUB			Diam. of   Hub at   Bevel
					Welding Neck		Slip-on	Lap Joint	Counter Bore MIn. Threaded Min.	Welding Neck	Slip-on Threaded	Lap Joint
	D	X	G	t	B1		B2	B3	B	T1	T2	T3	A
1/2	121	38.1	35.1	22.4	See Nole(1) To be specified by purchaser		22.4	22.9	23.6	60.5	31.8	31.8	21.3
3/4	130	44.5	42.9	25.4			27.7	28.2	29.0	69.9	35.1	35.1	26.7
1	149	52.3	50.8	28.4			34.5	35.1	35.8	73.2	41.1	41.1	33.5
1 1/4	159	63.5	63.5	28.4			43.2	43.7	44.5	73.2	41.1	41.1	42.2
1 1/2	178	69.9	73.2	31.8			49.5	50.0	50.5	82.6	44.5	44.5	48.3
2	216	104.6	91.9	38.1			62.0	62.5	63.5	101.6	57.2	57.2	60.5
2 1/2	244	124.0	104.6	41.1			74.7	75.4	76.2	104.6	63.5	63.5	73.2
3	241	127.0	127.0	38.1			90.7	91.4	92.2	101.6	53.8	53.8	88.9
4	292	158.8	157.2	44.5			116.1	116.8	117.6	114.3	69.9	69.9	114.3
5	349	190.5	185.7	50.8			143.8	144.5	144.5	127.0	79.2	79.2	141.2
6	381	235.0	215.9	55.6			170.7	171.5	171.5	139.7	85.9	85.9	168.4
8	470	298.5	269.7	63.5			221.5	222.3	222.3	162.1	101.6	114.3	219.2
10	546	368.3	323.9	69.9			276.4	277.4	276.4	184.2	108.0	127.0	273.1
12	610	419.1	381.0	79.2			327.2	328.2	328.7	200.2	117.3	142.7	323.9
14	641	450.9	412.8	85.9			359.2	360.2	360.4	212.9	130.0	155.4	355.6
16	705	508.0	469.9	88.9			410.5	411.2	411.2	215.9	133.4	165.1	406.4
18	787	565.2	533.4	101.6			461.8	462.3	462.0	228.6	152.4	190.5	457.2
20	857	622.3	584.2	108.0			513.1	514.4	512.8	247.7	158.8	209.6	508.0
24	1041	749.3	692.2	139.7			616.0	616.0	614.4	292.1	203.2	266.7	609.6

 

Nominal Pipe Sze	Radlus of FIllet	Thread Length	DRILLING			BOLTING				APPROXIMATE     WEIGHT
						Diam of Boits (inch)	Stud Bolt Length
			Bolt Circle Diam.	Number of Holes	Dlam of Holes		0.25" Raised Face	Male- Female Tongue- Groove	RIng Jolnt	Welding Neck		Slip-on and Threaded		Lap Joint		Blind
	R	Q								Kg	Ib	Kg	Ib	Kg	lb	Kg	Ib
1/2	3.0	22.4	82.6	4	22.4	3/4	108.0	101.6	108.0	2.10	4.60	1.81	4.00	1.81	4.00	1.90	4.20
3/4	3.0	25.4	88.9	4	22.4	3/4	114.3	108.0	114.3	2.72	6.00	2.40	5.30	2.30	5.00	2.70	6.00
1	3.0	28.4	101.6	4	25.4	7/8	127.0	120.7	127.0	3.86	8.50	3.41	7.50	3.40	7.50	4.09	9.00
1 1/4	4.8	30.2	111.3	4	25.4	7/8	127.0	120.7	127.0	4.54	10.00	4.10	9.00	4.09	9.00	4.54	10.00
1 1/2	6.4	31.8	124.0	4	28.4	1	139.7	133.4	139.7	5.90	13.00	5.45	12.00	5.40	11.90	5.90	13.00
2	7.9	38.1	165.1	8	25.4	7/8	146.1	139.7	146.1	10.89	24.00	9.98	22.00	9.53	21.00	11.34	25.00
2 1/2	7.9	47.8	190.5	8	28.4	1	158.8	152.4	158.8	16.33	36.00	15.80	34.80	13.15	29.00	16.00	35.30
3	9.7	41.1	190.5	8	25.4	7/8	146.1	139.7	146.1	15.00	33.00	11.80	26.00	11.34	25.00	13.17	29.00
4	11.2	47.8	235.0	8	31.8	1 1/8	171.5	165.1	171.5	23.13	51.00	23.20	51.00	22.60	48.50	24.50	54.00
5	11.2	53.8	279.4	8	35.1	1 1/4	190.6	184.2	190.5	38.50	84.90	37.65	83.00	36.74	81.00	39.46	87.00
6	12.7	57.2	317.5	12	31.8	1 1/8	190.5	184.2	196.9	49.89	110.00	48.30	106.50	47.50	104.70	51.50	113.50
8	12.7	63.6	393.7	12	38.1	1 3/8	222.3	215.9	222.3	79.45	175.00	75.00	166.30	86.00	189.60	89.00	106.20
10	12.7	71.4	469.9	16	38.1	1 3/8	235.0	228.6	235.0	118.04	260.00	111.13	245.00	125.64	277.00	131.54	290.00
12	12.7	76.2	533.4	20	38.1	1 3/8	254.0	247.7	254.0	157.00	346.00	146.00	321.80	167.00	368.00	187.00	412.30
14	12.7	82.6	558.8	20	41.1	1 1/2	273.1	266.7	292.1	181.60	400.40	172.36	380.00	180.07	397.00	224.07	494.00
16	12.7	85.9	616.0	20	44.5	1 5/8	285.8	279.4	298.5	224.73	495.50	192.95	425.40	211.11	465.40	272.40	600.50
18	12.7	88.9	685.8	20	50.8	1 7/8	323.9	317.5	333.6	308.72	680.60	272.40	600.50	295.10	650.60	385.90	850.80
20	12.7	91.9	749.3	20	53.8	2	349.3	342.9	362.0	376.82	830.70	331.42	730.60	367.74	810.70	488.00	1076.00
24	12.7	101.6	901.7	20	66.5	2 1/2	438.2	431.8	457.2	685.00	1510.00	632.00	1393.30	700.00	1543.00	905.00	1995.00

Notes:
(1) For the inside diameter of pipes(corresponding to 'Bore'(B1)of Welding Neck Flanges), refer to page 60.                                                                    
(2) Class 900 flanges except Lap Joint will be furnished with a 0.25"(6.35mm) raised face, which is not included in 'Thickness'(t) and Length through Hub' (T1), (T2).
(3) For Slip-on, Threaded, and Lap Joint Flanges, the hubs can be shaped vertically from base to top or tapered within the limits of 7 degrees.
(4) Bllnd Flanges may be made with the same hub as that used for Sllp-on Flanges or without a hub.                                                                    
(5) The gasket surace and backslde(bearlng surace for boltlng)are made parall withln 1 degree. Spot facing is carried out according to MSS SP-9, without reducing thickness(t) to accomplish parcels.                                                                    
(6) Dimensionsof sizes 1/2" through 2 1/2" are the same as for Class 1500 Flanges. 
                                                                 
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.