Lap Joint Flanges

What are Lap Joint Flanges?

Lap joint flanges, also known as loose flanges, are a type of flange that is commonly used in piping systems. Lap-joint flanges consist of two parts: a stub end and a backing lap joint flange. The stub end is the portion of the flange that is welded to the pipe, while the backing lap joint flange is the portion that is bolted to the other flange. Lap joint flange shape is similar to slip on flange, it has a curved radius at the bore, which can connect with a stub end and slide over the pipe. In this form, the pipe is usually welded to this stub end so the lap joint flange can rotate freely around the stub end.

What are Stub Ends?

Stub Ends also match both pipe material and wall schedule to maintain both inside and outside diameters of your piping system. This style is typically used in engineered piping systems with critical wall thickness requirements.

Lengths

Stub Ends are also available in two different lengths.

• MSS or Short lengths
• ASA or Long lengths

Face Finishes

Stub ends are available in different face finishes. Example is Serrated finish which can help to increase gasket adherence.

Types of Stub End  

A stub end is always used with a lap joint flange as a backing flange. There are three different types of stub ends, type A, B and C.

• Type A stub end can be machined to fit the standard lap joint support flange.
• Type B stub end is designed to be used with standard slip on flange.
• Either a lap joint flange or slip on flange, the type C stub end can be used

Stub end include long or short pattern length. The end of long pattern is also known as ASA Stub Ends. The short end is used with the larger flanges of ANSI 300 and 600. They are commonly used in most sizes ANSI 900 and above.

 

Lap joint flange consists of two parts namely The first piece of a lap flange is a sleeve called a “stub end”, which is shaped like a short section of pipe with a narrow shoulder at one end and a butt-weld end called a hub at the other end. The narrow shoulder is similar in size to the convex side of the flange and the butt weld end of the stub end is similar to the neck of a weld neck flange, depending on the diameter and thickness of the connecting pipe. The back of the hub has a circular transition that connects the hub to the sleeve.

The other piece of a lap joint flange is the backing flange.Backing flange dimensions are same with other common flanges(O.D. ,PCD,Bolt hole etc.),however it does not have a raised face (the stub end has the raised face).On One side of the lap joint flange,the backside,has a slight shoulder that is square cut at the center or pipe hole.The front side has flat face and at the center hole an outside fillet to match the fillet of the “Stub-end” piece.The flange part of the Lap-joint flange assembly is slipped on to the stub-end prior to the sleeve being welded to the pipe or fitting for connection.The flange itself is not welded or fixed in any way.It is free to spin for proper alignment with what ever it is joining to. Lap flange is an ideal solution for a wide range of industrial and pipeline applications. They are easy to install, widely used, cost-effective, durable and corrosion resistant, and are ideal for many industries. Whether you are engaged in oil and gas, power generation or chemical processing, lap flange is a reliable and effective solution to meet your pipeline needs.

Standard Specication For Lap Joint 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.
• DIN : DIN2527, DIN2566, DIN2573, DIN2576, DIN2641, DIN2642, DIN2655, DIN2656, DIN2627, DIN2628, DIN2629,
• DIN 2631, DIN2632, DIN2633, DIN2634, DIN2635, DIN2636,DIN2637, DIN2638, DIN2673
• BS : BS4504 , BS4504, BS1560, BS10
• Flange Face Type : Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)

Standard of lap joint flanges

Pipe Flange Standards mainly include three systems in the world, ANSI/ASME flange system(American), DIN flange system(European system), JIS flange system, other system made according to this three systems, like GB flange standard, which mainly made according to ANSI/ASME and DIN flange standard, Jihua supplies those flanges with top quality and soonest delivery time.

ASME standards

• ASME B16.1 – Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
• ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
• ASME B16.20 – Ring Joint Gaskets and Grooves for Steel Pipe Flanges
• ASME B16.21 – Nonmetallic Flat Gaskets for Pipe Flanges
• ASME B16.24 – Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500, and 2500
• ASME B16.34 – Large Diameter Steel Flanges (NPS 26 through NPS 60)
• ASME B16.36 – Orifice Flanges
• ASME B16.42 – Ductile Iron Pipe Flanges and Flanged Fittings: Classes 150 and 300
• ASME B16.47 – Large Diameter Steel Flanges (NPS 26 Through NPS 60)

ASTM standards

• ASTM A105 – Specification for Carbon Steel Forgings for Piping Applications
• ASTM A182 – Specification for Forged or Rolled Alloy Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service
• ASTM A193 – Specification for Alloy Steel and Stainless Steel Bolting Materials for High Temperature Service
• ASTM A194 – Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service
• ASTM A694 – Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service
• ASTM A707 – Specification for Flanges, Forged, Carbon and Allow Steel for Low Temperature Service

AWWA standards

• AWWA C115 – Standard for Flanged Ductile Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges
• ISO standards
• ISO 5251 – Stainless steel butt-welding fittings
• MSS standards
• MSS SP-6 – Standard Finishes for Contact Faces Pipe Flanges and Connecting End Flanges of Valves and Fittings
• MSS SP-9 – Spot Facing for Bronze, Iron and Steel Flanges
• MSS SP-25 – Standard Marking Systems for Valves, Fittings, Flanges, and Unions
• MSS SP-44 – Steel Pipeline Flanges
• MSS SP-53 – Quality Standards for Steel Castings and Forgings for Valves, Flanges and Fittings and Other Piping Components – Magnetic Particle
• MSS SP-54 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Radiographic
• MSS SP-55 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Visual
• MSS SP-75 – High Test Wrought Butt Welding Fittings
• MSS SP-106 – Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300

ASME B16.5 and ASME B16.47 cover pipe flanges up to NPS 60 (B16.5 from 1/2″ to 24″ and B16.47 from 26″ to 60″). ANSI B16.47 covers two series of flanges, Series A is equal to MSS SP-44-44, and Series B is equal to API 605 (API 605 has been canclled).

Advantages and disadvantage of Lap Joint Flanges

Lap joint flanges are designed to connect pipes and other equipment in a secure and reliable manner. We will explore the advantages and disadvantages of lap joint flanges to help you determine if they are the right choice for your specific needs.

Advantages of Lap Joint Flanges:

• Easy to install: Lap joint flanges are relatively easy to install, making them a popular choice for both industrial and residential applications. They can be easily attached to pipes using bolts, which makes them a convenient option for those who are not experienced in welding or other types of pipe installation.
• Flexibility: One of the main advantages of lap joint flanges is their flexibility. They can be easily adjusted to fit different pipe sizes and configurations, which makes them a versatile option for a wide range of industrial applications.
• Cost-effective: Lap joint flanges are generally less expensive than other types of flanges, which makes them a cost-effective option for many industrial applications. This is especially true for projects that require a large number of flanges.

Disadvantages of Lap Joint Flanges:

• Not as strong as other flanges: While lap joint flanges are a reliable option for many applications, they are not as strong as other types of flanges. This can be a concern for some industrial applications that require a high level of strength and durability.
• Not suitable for high-pressure applications: Lap joint flanges are not designed to handle high-pressure applications, which can be a concern for some industrial applications.
• Limited use in specific industry: Lap joint flanges are not suitable for use in certain industries, such as the oil and gas industry, where high-pressure and high-temperature applications are common.

Lap joint flanges have several advantages, including being easy to install, flexible, and cost-effective. However, they also have some disadvantages, such as not being as strong as other flanges, not suitable for high-pressure applications, and limited use in specific industries. Therefore, it is important to consider the specific requirements of your application before choosing lap joint flanges.

What are the different types of sealing faces used on lap joint flanges?

The different types of sealing faces used on lap joint flanges are raised face (RF), flat face (FF), and ring-joint face (RTJ). The raised face has a small raised ring around the circumference of the flange, the flat face is smooth and flat, and the ring-joint face has a circular groove with a precision-machined ring-shaped groove. The type of sealing face used will depend on the specific application and the type of gasket being used.

1. The first type of sealing face is the raised face. This type of face is created by machining a small raised surface on the flange. The raised surface provides a small area for the gasket to seal against, which helps to prevent leaks. The raised face is the most common type of sealing face and is used in a wide range of applications.
2. The second type of sealing face is the flat face. This type of face is created by machining the entire surface of the flange to be flat. The flat surface provides a large area for the gasket to seal against, which helps to prevent leaks. The flat face is typically used in low-pressure applications where a raised face is not necessary.
3. The third type of sealing face is the ring-joint face. This type of face is created by machining a small circular groove on the flange. The groove is designed to accept a ring-joint gasket, which is a specially designed gasket that is made to fit into the groove. The ring-joint gasket provides a tight seal, which helps to prevent leaks. The ring-joint face is typically used in high-pressure applications where a raised or flat face would not provide enough seal.

Each type of sealing face has its own unique advantages and is used in different types of applications. It is important to select the right type of sealing face for your specific application to ensure that your pipe system operates safely and efficiently.

Material of Lap Joint Flanges

Lap joint flanges are typically made from carbon steel, stainless steel, or alloy steel. They are also available in other materials such as plastic, aluminum, or bronze, depending on the application.  

Stainless Steel Lap Joint Flange	ASTM/ASME A/SA182:- F304, F304L, F316, F316L, ASTM/ASME A/SA351:- CF3, CF3M, CF8, CF8M, DIN 1.4306, DIN 1.4301, DIN 1.4404, DIN 1.4401, DIN 1.4408, DIN 1.4308, DIN 1.4306, DIN 1.4409
Duplex Lap Joint Flange	S31803 / S32205 A182:- Gr F51 / F52
Super Duplex Lap Joint Flange	S32750 / S32760 A182:- Gr F53 / F54 / F55 / F57 / F59 / F60 / F61
Copper Nickel Lap Joint Flange	ASTM / ASME SB 61 / 62 / 151 / 152, Copper Nickel 90/10 (C70600 ), Cupro Nickel 70/30 (C71500), UNS C71640
Titanium Lap Joint Flange	ASTM B381 / ASME SB381:- Titanium Gr. 1, Titanium Gr. 2, Titanium Gr. 4, Titanium Gr. 5, Titanium Gr. 7, ASTM  R50250/GR.1 | R50400/GR.2 | R50550/GR.3 | R50700/GR.4 | GR.6 |R52400/GR.7 | R53400/GR.12 | R56320/GR.9 | R56400/GR.5
Copper Lap Joint Flange	TP1, TP2, C10930, C11000, C11300, C11400, C11500, C11600, C12000, C12200, C12300, T1, T2, C10100, C10200, C10300, C10400, C10500, C10700, C10800, C10910, C10920, TU1, TU2, C12500, C14200, C14420, C14500, C14510, C14520, C14530, C17200, C19200, C21000, C23000, C26000, C27000, C27400, C28000, C33000, C33200, C37000, C44300, C44400, C44500, C60800, C63020, C68700, C70400, C70600, C70620, C71000, C71500, C71520, C71640, etc
Incoloy Lap Joint Flange	ASTM B564 / ASME SB564:- Incoloy 800, 800H, 800HT (UNS N08800), 825 (UNS N08825), 925
Inconel Lap Joint Flange	ASTM B564 / ASME SB564:- Inconel 600, 601, 625, 718, 783, 690, x750
Nickel Lap Joint Flange	ASTM B564 / ASME SB564:- Nickel 200, Nickel 201, Nickel 205, Nickel 205LC
Hastelloy Lap Joint Flange	ASTM B564 / ASME SB564:- Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X
Monel Lap Joint Flange	ASTM B564 / ASME SB564:- Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500)
Carbon Steel Lap Joint Flange	ASTM/ASME A/SA105 A/SA105N and A/SA216-WCB, DIN 1.0460, DIN 1.0402, DIN 1.0619, Die Steel, ASTM A105 / ASME SA105, A105N, ASTM A350 LF2 / ASME SA350, CS High Yield ASTM A694 / A694 (F52, F56, F60, F65, F70, F80)
Alloy Steel Lap Joint Flange	ASTM A182 / ASME SA182:- F5, F9, F11, F12, F22, F91
Alloy 20 Lap Joint Flange	ASTM B462 / ASME SB462:- Carpenter 20 Alloy, Alloy 20Cb-3
254 SMO Lap Joint Flange	ASTM A182 / ASME SA182:- SMO 254/6Mo, UNS S31254, DIN 1.4547
Aluminium Lap Joint Flange	5052 /6061/ 6063 / 2017 / 7075 / etc.
Brass Lap Joint Flange	3602 / 2604 / H59 / H62 / etc.
Other Lap Joint Flange material	Tin bronze, Alumunum bronze, Lead bronze, Nimonic 75, Nimonic 80A, Nimonic 90, AISI 4140, AISI 4130, Mild Steel, Al6XN

Size of Lap Joint Flanges

Lap joint flanges are typically smaller in size than other types of flanges, such as slip-on or weld neck flanges. The size of a lap joint flange is determined by the size of the pipe it is being used with, and the size is usually specified as the nominal pipe size (NPS), which is the inside diameter of the pipe. The outside diameter of a lap joint flange will be slightly larger than the inside diameter of the pipe it is being used with, and the flange will typically have a raised face or ring that is used to mate with a lap joint stub end.

Dimensions of Lap Joint Flanges

Lap joint flanges are typically available in sizes ranging from 1/2 inch to 24 inches in diameter, but can be custom made to accommodate larger sizes. The standard thickness for lap joint flanges is 1/4 inch, but can also be made in other thicknesses. The bolt circle diameter and number of bolt holes vary depending on the size of the flange.

Dimensions of ASME B16.5 Lap Joint Flange

ASME B16.5 lap joint flange dimensions from ½” to 24”. For sizes larger than this (ASME B16.47 Series A & B).  

Class
ANSI 150	Lap Joint, ANSI Class 150 (mm)
ANSI 300	Lap Joint, ANSI Class 300 (mm)
ANSI 400	Lap Joint, ANSI Class 400 (mm)
ANSI 600	Lap Joint, ANSI Class 600 (mm)
ANSI 900	Lap Joint, ANSI Class 900 (mm)
ANSI 1500	Lap Joint, ANSI Class 1500 (mm)
ANSI 2500	Lap Joint, ANSI Class 2500 (mm)

Dimensions of Class 150 ASME B16.5 Lap Joint Flanges

The dimensions are in millimeters Source : ASME B16.5 – 2007

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Lapped Thick.	Lapped ID	PCD	Lapped Thick.	Lapped Radius	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	G
1/2	15	90	30	16	22.9	60.3	11.2	3	4	1/2	50	55	5/8	M14	0.8
3/4	20	100	38	16	28.2	69.9	12.7	3	4	1/2	50	65	5/8	M14	0.9
1	25	110	49	17	34.9	79.4	14.3	3	4	1/2	55	65	5/8	M14	0.9
1 1/4	32	115	59	21	43.7	88.9	15.9	5	4	1/2	55	70	5/8	M14	1.4
1 1/2	40	125	65	22	50	98.4	17.5	6	4	1/2	65	70	5/8	M14	1.4
2	50	150	78	25	62.5	120.7	19.1	8	4	5/8	70	85	3/4	M16	2.3
2 1/2	65	180	90	29	75.4	139.7	22.3	8	4	5/8	75	90	3/4	M16	3.2
3	80	190	108	30	91.4	152.4	23.9	10	4	5/8	75	90	3/4	M16	3.7
3 1/2	90	215	122	32	104.1	177.8	23.9	11	8	5/8	75	90	3/4	M16	5
4	100	230	135	33	116.8	190.5	23.9	11	8	5/8	75	90	3/4	M16	5.9
5	125	255	164	36	144.4	215.9	23.9	11	8	3/4	85	95	7/8	M20	6.8
6	150	280	192	40	171.4	241.3	25.4	13	8	3/4	85	100	7/8	M20	8.6
8	200	345	246	44	222.2	298.5	28.6	13	8	3/4	90	110	7/8	M20	13.7
10	250	405	305	49	277.4	362	30.2	13	12	7/8	100	115	1	M24	19.5
12	300	485	365	56	328.2	431.8	31.8	13	12	7/8	100	120	1	M24	29
14	350	535	400	79	360.2	476.3	35	13	12	1	115	135	1 1/8	M27	41
16	400	595	457	87	411.2	539.8	36.6	13	16	1	115	135	1 1/8	M27	54
18	450	635	505	97	462.3	577.9	39.7	13	16	1 1/8	125	145	1 1/4	M30	59
20	500	700	559	103	514.4	635	42.9	13	20	1 1/8	140	160	1 1/4	M30	75
24	600	815	663	111	616	749.3	47.9	13	20	1 1/4	150	170	1 3/8	M33	100

Dimensions of Class 300 ASME B16.5 Lap Joint Flanges

Dimensions of Class 400 ASME B16.5 Lap Joint Flanges

Dimensions of Class 600 ASME B16.5 Lap Joint Flanges

Dimensions of Class 900 ASME B16.5 Lap Joint Flanges

Dimensions of Class 1500 ASME B16.5 Lap Joint Flanges

Dimensions of Class 2500 ASME B16.5 Lap Joint Flanges

Size in Inch	Size in mm	Outer Diameter	Flange Thick.	Lapped Thick.	Lapped ID	PCD	Lapped Thick.	Lapped Radius	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	G
1/2	15	135	43	40	22.9	88.9	30.2	3	4	3/4	120	7/8	M20	3.2
3/4	20	140	51	43	28.2	95.2	31.8	3	4	3/4	125	7/8	M20	3.7
1	25	160	57	48	34.9	108	35	3	4	7/8	140	1	M24	5
1 1/4	32	185	73	52	43.7	130.2	38.1	5	4	1	150	1 1/8	M27	7.5
1 1/2	40	205	79	60	50	146	44.5	6	4	1 1/8	170	1 1/4	M30	10
2	50	235	95	70	62.5	171.4	50.9	8	8	1	180	1 1/8	M27	17.5
2 1/2	65	265	114	79	75.4	196.8	57.2	8	8	1 1/8	195	1 1/4	M30	23
3	80	305	133	92	91.4	228.6	66.7	10	8	1 1/4	220	1 3/8	M33	37.8
4	100	355	165	108	116.8	273	76.2	11	8	1 1/2	255	1 5/8	M39	57
5	125	420	203	130	144.4	323.8	92.1	11	8	1 3/4	300	1 7/8	M45	95
6	150	485	235	152	171.4	368.3	108	13	8	2	345	2 1/8	M52	148
8	200	550	305	178	222.2	438.2	127	13	12	2	380	2 1/8	M52	221
10	250	675	375	229	277.4	539.8	165.1	13	12	2 1/2	490	2 5/8	M64	425
12	300	760	441	254	328.2	619.1	184.2	13	12	2 3/4	540	2 7/8	M72	500

Pressure Ratings of ASME B16.5 Lap Joint Flanges

Pressure rating of Flanges (in psig)
Temperature (F°)	150#	300#	400#	600#	900#	1500#	2500#
-20 to 100	285	740	985	1480	2220	3705	6170
200	260	680	905	1360	2035	3395	5655
300	230	655	870	1310	1965	3270	5450
400	200	635	845	1265	1900	3170	5280
500	170	605	805	1205	1810	3015	5025
600	140	570	755	1135	1705	2840	4730
650	125	550	730	1100	1650	2745	4575
700	110	530	710	1060	1590	2655	4425
750	95	505	675	1015	1520	2535	4230
800	80	410	550	825	1235	2055	3430
850	65	320	425	640	955	1595	2655
900	50	230	305	460	690	1150	1915
950	35	135	185	275	410	685	1145
1000	20	85	115	170	255	430	715

Dimensional Tolerances of ASME B16.5 Lap Joint Flanges

Notes

• 1. Dimensions are in millimeters unless otherwise indicated.
• 2. The length of the stud bolt does not include the height of the chamfers (points).

Manufacturing process of Lap Joint Flanges

Lap joint flanges are typically manufactured using a process called forging. This process involves heating a piece of steel to a high temperature, and then shaping it into the desired shape using a press or hammer. The steel is then cooled and the flange is cut and drilled to the appropriate size and shape. Other manufacturing process for lap joint flanges include casting, cutting and welding.

Production process of forged lap joint flange

The manufacturing process for forged lap joint flanges typically involves the following steps: Cutting the raw materials to size: The first step in the manufacturing process is to cut the raw materials to the required size and shape. This typically involves cutting sheets of metal, such as carbon steel or stainless steel, using a cutting machine. Forming the flange: Once the raw materials have been cut to size, the next step is to form the flange. This typically involves using a die-stamping machine to shape the metal into the desired flange shape. Heat treating the flange: Once the flange has been welded, it must be heat treated to improve its strength and durability. This typically involves heating the flange to a high temperature and then rapidly cooling it to harden the metal. Machining the flange: After the flange has been heat treated, it must be machined to achieve the desired level of precision and to create the necessary bolt holes and other features. This typically involves using a lathe or other machining equipment to shape the flange to the required specifications. Drilling holes in the flange for bolts to connect it to other components. Cleaning and preparing the surface of the flange for finishing. Applying a protective coating such as paint or galvanization to protect the flange from corrosion. Testing the flange to ensure it meets the required specifications and tolerances. Packaging the flange for shipping or storage. These steps may vary slightly depending on the specific type of flange being manufactured and the requirements of the application it will be used in.

Production process of casting lap joint flange

Casting lap joint flanges requires several steps. First, metal (usually iron or steel) is melted in a furnace and then poured into a mold. Moulds are usually made of sand and have the shape of the required flange, including the hole in the center. Once the metal cools and solidifies, the mold breaks and the flange is removed. They are then cleaned, inspected, and frequently machined to achieve the required dimensions and finish. Finally, the flange is ready for use.

Production process of cutting lap joint flange

The production process of cutting a lap joint flange typically involves the following steps: The raw materials, such as steel plates, are cut to size and shape using a cutting machine, such as a plasma cutter or laser cutter. The cut pieces are then machined to the desired dimensions and tolerances using a variety of machine tools, such as lathes, mills, and drills. The flange is then heat treated to improve its strength and durability. This can involve heating the flange to a high temperature and then quenching it in oil or water. The flange is then sandblasted to remove any surface imperfections and to improve its surface finish. Any holes or bolt holes are then drilled or punched into the flange using specialized machines. The flange is then inspected for quality and conformity to specifications. If necessary, the flange may be coated with a protective coating to prevent corrosion and improve its appearance. The flange is then packaged and shipped to the customer.

Process of lap joint flange machining with CNC lathe

Machining of flanges

Turning the inner and outer circle of the flange: (manhole cover only turning the outer circle). Put the flange or manhole cover blank on the turning bed chuck, find the correctness and then clamp it tightly to prevent it from falling off and injuring people. Choose a suitable tool and tighten the tool. After starting turning, in order to prevent over-turning, the diameter should be constantly measured with calipers. After turning qualified to check the turning surface is not allowed to have cracks, delamination, slag, impurities and other defects. Material mark and part number mark moved to the outer plane, confirmed by the inspector to hit the confirmation steel seal.

Turning the two end faces of the flange

After processing the inner and outer circle, one end face is processed first until it is completely processed and leveled, then the other end face is processed. Processing of the other end face to prevent over-processing should be constantly measured with calipers its thickness, qualified until. Check the processing surface shall not have cracks, delamination, slag, inclusions and other defects. Turning the sealing surface of the flange

Flange and manhole cover without lining ring can be directly processed after turning the two end faces sealing surface. With the liner ring flange and into the hole cover in the group welding liner ring, re-on the turning bed on the chuck, find the right after the card tight, and then the sealing surface processing. The roughness of the sealing surface is according to the design drawings.

Scribing and drilling of flange

According to the design drawings or flange and manhole cover standards given in the bolt hole center circle diameter and the number of bolt holes scribe the bolt hole center position, and hit the foreign punching eye one by one. Check the drilling surface shall not have cracks, delamination, slag, inclusions and other defects. Check the adjacent two bolt hole center distance deviation is not more than ± 0.6mm, any two bolt holes, the center distance deviation is not more than ± 1mm.

Marking of Lap Joint Flanges

Lap joint flanges are typically marked with the manufacturer’s name or trademark, the size of the flange, and the material grade. They may also include other markings such as pressure ratings, heat numbers, or serial numbers. The markings are typically stamped or engraved on the flange surface. It is important to note that the lap joint flange does not have a raised face, so these markings will typically be located on the flat surface of the flange. It is typically marked with the following information:

• Material grade (e.g. ASTM A105, A350 LF2)
• Size (e.g. 10″ x 4″ or DN 250 x 100)
• Pressure rating (e.g. 150#, 300#, 600#)
• Manufacturer’s name or logo
• Heat number (for traceability)
• Standard (e.g. ASME, ANSI, API)
• Optional: Additional markings like “RF” (raised face) “FF” (flat face)

Example:

ASTM A105 10″ x 4″ 150# RF, ABC Inc. Heat No. 123456, ANSI B16.5

Note that the above is an example and standard/requirement may vary by industry or country. Marking of lap joint flanges is an important aspect of their design and use. It helps to identify the flange, ensure that it is used correctly, and that it meets necessary safety and performance standards. Properly marked lap joint flanges are a crucial component of safe and efficient industrial piping systems.

Packing and transportation of lap joint flanges

When it comes to the packing and transportation of lap joint flanges, it’s important to take the necessary precautions to ensure that they arrive at their destination in good condition. These flanges, which are used in piping systems to connect sections of pipe together, are made of durable materials such as carbon steel and stainless steel. However, they can still be damaged during transport if not properly packed and handled. One of the first steps in packing lap joint flanges is to make sure they are clean and free of debris. Any dirt or debris on the flanges can cause scratches or other damage during transport. Once the flanges are clean, they should be wrapped in protective material such as bubble wrap or foam. This will help to cushion the flanges and prevent them from being damaged during transport. It’s also important to choose the right type of packaging for the flanges. Wooden crates are a popular choice for shipping lap joint flanges, as they provide a sturdy and secure environment for the flanges during transport. The crates should be properly sealed and labeled with the appropriate information, such as the destination and contents. When it comes to transportation, it’s important to choose a reputable and experienced shipping company. The company should have experience in handling and transporting industrial products such as lap joint flanges. They should also have proper equipment and personnel to ensure that the flanges are loaded and unloaded safely. In addition to the above, it is important to make sure the flanges are properly secured during transport to prevent them from shifting or moving around in the crate or truck. This can be done by using straps or other types of restraints to hold the flanges securely in place. In conclusion, the packing and transportation of lap joint flanges is an important process that requires care and attention to detail. By taking the necessary steps to properly clean, pack, and transport the flanges, you can ensure that they will arrive at their destination in good condition and ready for use.

Inspection and measurement of Lap Joint Flanges

In order to ensure that the lap joint flange works normally, it is very important to check and measure the lap joint flange regularly to ensure that it is in good condition and meets the necessary specifications. To inspect lap joint flanges, visually inspect for any signs of damage or defects, such as cracks, dents, or corrosion. The flanges should also be checked for correct alignment and any signs of leakage. To measure the lap joint flange, check several different dimensions. The first is the outer diameter of the flange, that is, the distance at the widest part of the flange. The second is the inner diameter of the flange, that is, the distance through the flange opening. The third is the thickness of the flange, that is, the distance from the outer surface of the flange to the inner surface. Other dimensions that can be measured include the bolt hole diameter of the flange and the distance between the bolt holes. When measuring lap joint flanges, be sure to use appropriate tools and techniques to ensure accurate results. This may include the use of a tape measure, caliper or micrometer, depending on the required accuracy. Special measuring equipment, such as bore gauges or flange alignment tools, may also be required to accurately measure flange dimensions. The inspection and measurement of lap joint flange is an important step to ensure its correct installation and safe operation in the pipeline or pressure vessel system.

Application of Lap joint flanges

The lap joint flange is commonly used in situations where the piping system needs to be disassembled or adjusted frequently, as the backing flange can be easily removed and reattached. They are also used in applications where a smooth bore is required. These Lap Joint Flange is use in various industries like:

• Lap Joint Flanges are used in Oil and Gas Pipeline;
• Lap Joint Flanges are used in Chemical Industry;
• Lap Joint Flanges are used in Plumbing;
• Lap Joint Flanges are used in Heating;
• Lap Joint Flanges are used in Water Supply Systems;
• Lap Joint Flanges are used in Power Plant;
• Lap Joint Flanges are used in Paper & Pulp Industry;
• Lap Joint Flanges are used in General Purpose Applications;
• Lap Joint Flanges are used in Fabrication Industry;
• Lap Joint Flanges are used in Food Processing Industry;
• Lap Joint Flanges are used in Structural Pipe.

What is the difference between a lap joint flange and a rolled angle ring?

Rolled angle rings (also known as Vanstone rings or Vanstone rolled angle rings) offer similar benefits to lapped short ends with similar design and installation requirements. Rolled angle rings are not a standard fitting. In most cases, there are minor differences between the two that make one side superior to the other. As with lap joint flanges, the two-part design means that the rolled angle ring and backing flange can be composed of different materials for added flexibility and cost optimization potential.  

Example of rolled angle ring: 316/L stainless steel rolled angle ring with carbon steel, galvanized backing flange.

Backing flanges can also be freely rotated on the pipe for easier alignment. Unlike lap joint flanges, rolled angle rings are available in two different mounting configurations.

• Butt-welded  

Slip-On Butt-welded rolled angle rings are installed similar to the short end of a lap joint and need to be welded to the end of the pipe and matched to the inside diameter of the pipe or fitting in use. Slip rolled angle rings slide over the pipe and attach to the outside of the pipe wall rather than the end. Rolled angle rings are also not manufactured to match the thickness of the pipe or fitting to which they are attached. They are mostly made from 11 gauge angle steel. Larger pipe sizes may use 7-gauge angle iron. Smaller rings are made by using a hydraulic press to cut a piece of plate to a specific inside and outside dimension. These are called pressed angle rings or inside diameter pressed Vanstone rings. They are seamless rings that are easy to produce and reproduce. However, it is difficult to obtain the exact 90 degree angle of a rolled angle ring using a hydraulic press.

Advantages and disadvantages of lap joint flanges and rolled angle rings.

After learning how these common flange types work, we will discuss why you should use them in your piping system.

Disadvantages

The biggest limitation on the use of lap joint flanges is the pressure rating. Similar to sliding flanges, lap joint flanges cannot be used in high pressure applications. It is necessary to consult with a piping materials engineer to determine the feasibility of lap joint flanges in certain high pressure applications. Butt weld flanges are typically used in high pressure applications.

Advantages

For lap joint flanges, we can use a different backing flange material than for short ends or angle rings. This means you can use a pipe material that is compatible with the fluid passing through the pipe for the short end, or you can use a more affordable or desirable material for a swivel flange that does not interact with the process fluid. A second advantage is the ability to realign and freely rotate flanges to ensure proper connection to valves and other flanged components of the piping system. It greatly speeds up the maintenance process for systems that require frequent maintenance. Overlap joint flanges do not require fillet welds on the plate. This fact reduces installation time and provides further upfront cost savings. In highly corrosive and erosive processes, frequent pipe replacement may be required. In such cases, only the short end portion of this flange needs to be replaced. The backing flange can be reused, saving on pipe replacement costs.

Differences between lap joint flange and slip on flange?

A lap joint flange is a type of flange that is designed to be used with a lap joint stub end. It is a two-piece design that allows for easy alignment and installation. A slip-on flange is a type of flange that is designed to be slipped over the end of a pipe and then welded in place. The main difference between the two is the way they connect to the pipe. A lap joint flange is connected to a stub end, while a slip-on flange is directly welded to the pipe. Additionally, the lap joint flange has a radius at the intersection of the bore and the flange face, which means that it can accommodate misalignment between the two pipes it is connecting.

Why choose lap joint flanges?

Lap joint flanges are typically used in low-pressure systems or systems that require frequent dismantling. The following are the main reasons for selecting loose flanges:

• 1. Due to the construction of the lap joint flange, it can be rotated around the short pipe end and pipe lining. When piping systems are assembled and disassembled frequently, it is best to use lap joint flanges. This means that the flange can work even if the two flange bolt holes are not aligned.
• 2. In corrosive situations, flange joints need to be replaced quickly. With lap joint flanges, only the stub end is in contact with the pipe and fluid; the backing flange does not need to be in contact. This means that only the stub end can be replaced without replacing the backing flange, so lap joint flanges can reduce the cost of the piping system.
• 3. The backing flange and the stub end are separate, so we can use two different materials for these two pieces. It can be used for more complex applications.

How to purchase the correct lap joint flanges?

Purchasing the correct lap joint flanges for your specific application can be a bit of a challenge. Here are some tips to help you make the right choice. First, it’s important to understand the different types of lap joint flanges available. There are two main types: standard and long pattern. Standard lap joint flanges have a shorter hub and are typically used in low-pressure applications. Long pattern lap joint flanges have a longer hub and are typically used in higher-pressure applications. Next, you’ll need to consider the size and pressure rating of the lap joint flanges. The size should match the size of the pipe or equipment you’re connecting to. The pressure rating should be equal to or greater than the maximum pressure that will be present in the system. You will also want to consider the material of the lap joint flanges. These flanges come in a variety of materials such as steel, stainless steel, and alloy. Make sure to choose a material that is compatible with the fluid or gas that will be flowing through the system and will withstand the temperature, pressure and corrosion of the environment. Finally, you’ll want to consider the connection type of the lap joint flanges. These flanges can be connected to pipes and equipment using a variety of methods such as welding, brazing, or using gaskets. Make sure to choose a connection type that is compatible with the other components in your system. Purchasing the correct lap joint flanges for your specific application involves considering the types, size, pressure rating, material, and connection type of the flanges. By following these tips, you can ensure that you select the best lap joint flanges for your needs and minimize the risk of leaks or other problems in your piping system.

How to select lap joint flange manufacturer?

When selecting a manufacturer for lap joint flanges, it is important to consider factors such as:

• Quality: Look for a manufacturer that uses high-quality materials and adheres to industry standards for manufacturing.
• Experience: Choose a manufacturer with experience in producing lap joint flanges. This will ensure that they have the knowledge and expertise to produce a high-quality product.
• Lead time: Consider the manufacturer’s lead time for delivering the flanges. Choose a manufacturer that can deliver the flanges in a timely manner to meet your project schedule.
• Cost: Compare prices from multiple manufacturers to ensure that you are getting the best value for your money.
• Customer service: Look for a manufacturer that offers good customer service. This will ensure that any issues or concerns can be addressed quickly and efficiently.
• Brand reputation: check for the manufacturer’s reputation in the market, it’s reliability and customer satisfaction.
• Certifications and compliance: Check if the manufacturer holds any relevant certifications and is compliant with industry regulations.
• Location: Choose a manufacturer that is geographically located close to your facility to minimize transportation costs and delivery time.

It is also recommended to visit the manufacturer’s facility and to inspect the production process and quality control measures in place.  

Export Country For Lap Joint Flanges

MIDDLE EAST	AFRICA	NORTH AMERICA	EUROPE	ASIA	SOUTH AMERICA
Saudi Arabia	Nigeria	Usa	Russia	India	Argentina
Iran	Algeria	Canada	Norway	Singapore	Bolivia
Iraq	Angola	Mexico	Germany	Malaysia	Brazil
Uae	South Africa	Panama	France	Indonesia	Chile
Qatar	Libya	Costa Rica	Italy	Thailand	Venezuela
Bahrain	Egypt	Puerto Rica	Uk	Vietnam	Colombia
Oman	Sudan	Trinidad And Tobago	Spain	South Korea	Ecuador
Kuwait	Equatorial Guinea	Jamaica	Ukraine	Japan	Guyana
Turkey	The Republic Of Congo	Bahamas	Netherland	Sri Lanka	Paraguay
Yemen	Gabon	Denmark	Belgium	Maldives	Uruguay
Syria			Greece	Bangladesh
Jordan			Czech Republic	Mayanmar
Cyprus			Portugal	Taiwan
			Hungary	Cambodia
			Albania
			Austria
			Switzerland
			Slovakia
			Finland
			Ireland
			Croatia
			Slovenia
			Malta