Lap Joint Stub End Specification

Performance Characteristics:

Convenient Connection: by cooperating with loose-set flange and adopting bolt connection, it is convenient to install and dismantle, which facilitates the maintenance and replacement of pipeline.

Good sealing: Utilizing the flange sealing structure, it can effectively prevent medium leakage and guarantee the safe operation of the pipeline system.

Strong adaptability: it can be applied to pipeline systems with a variety of media and temperature conditions, and can be used under different working conditions in petroleum, chemical, natural gas and other industries.

Types of Lap Joint Stub End

Type A

Type A stub ends are used for standard lap joint flanges. The lap thickness at the stub end is greater than or equal to the nominal thickness of the pipe wall. In addition, Type A has an outside corner radius to accept lap flanges. The inside corners are square. The lap usually has a machined serrated face.

Type B

Type B short ends are used as lap joint flanges for standard slip on flanges. The lap thickness of these short ends is greater than or equal to the nominal thickness of the pipe wall. In addition, the outside corner radius of Type B is small enough to accommodate a slip-on flange that can be used as a backup flange. The inside corners are square. The lap usually has a machined serrated face.

Type C

Type C stumps are available for standard lap joint flanges and slip-on flanges. It is flared with a rounded edge at the lap ID. If necessary, the radius can be squared. The lap thickness is 75% of the pipe wall. type C pipe is short enough to accommodate any spare flanges. type C laps are smooth and do not require machining.

You can view the exact specifications on our [Stub End Type A] product detail page.

Long Pattern Stub End and Short Pattern Stub End

1. Long Pattern Stub End

The Long Pattern Stub End usually has a long straight section, which makes it excellent in applications where a long connection length is required or where there are special requirements for pipe support. It provides better stability and reduces the effects of pipe vibration or displacement.

Advantage:

Smoother Fluid Paths: Longer straight sections of pipe help reduce turbulence in the transition to the flanged connection, providing a smoother fluid flow. This is especially important for systems with stringent requirements for fluid resistance or pressure loss.

Better welding conditions: Longer lengths provide more maneuvering space for welding, especially when welding in the field.

2. Short Pattern Stub End

Short Pattern Stub Ends are relatively compact, with short straight sections that are advantageous in space-constrained installations, allowing greater flexibility in adapting to pipe connections in confined spaces.

Advantage:

Space-saving: Due to their compact construction, short flanged short sections are very popular in piping layouts where space is limited.

Lighter weight: Shorter lengths mean less material is used, reducing weight and costs.

Wider applicability: In applications with less demanding hydrodynamic requirements, the Short Flap is a more economical and practical choice.

Material & Grades of Buttweld Lap Joint Stub End :

Stainless Steel Buttweld Lap Joint Stub End :
A403 WP304/304L/304H – WP316/316L – WP317 – WP310S – WP321 – WP347 – WP904L  

Duplex & Super Duplex Steel Buttweld Lap Joint Stub End :
A815 WPS32205/32750/31803/32760

Carbon Steel Buttweld Lap Joint Stub End :
ASTM A234 WPB / WPC, ASTM 420 WPL 3 / 6 / 9, A860 WPHY 42 / 46 / 52 / 56 / 65 / 70   

Alloy Steel Buttweld Lap Joint Stub End :
A234 WP5 / WP9 / WP11 / WP12 / WP22 /WP 91 / WP92

Nickel Alloy Buttweld Lap Joint Stub End :
ASTM B336, ASME SB336, Nickel 200 (UNS No. No2200), Nickel 201 (UNS No. N02201), Monel 400 (UNS No.N04400), Monel 500 (UNS No. N05500), Inconel 800 (UNS No. N08800), Inconel 825 (UNS No. N08825), Inconel600 (UNS No. N06600), Inconel 625 (UNS No. N06625), Inconel 601 (UNS No. N06601), Hastelloy C 276 (UNS No.N10276), Alloy 20 (UNS No. N08020), Titanium (Grade I & II), Cupro-Nickel 70/30, CuNi10Fe1Mn, CuNi30Mn1Fe.

Dimensions of ASME B16.9 Lap Joint Stub End

Advantages of Stub Ends

Cost-effective: Where expensive, corrosion-resistant materials (e.g. stainless steel, nickel alloys) are used in the piping system, they can be used only in the part of the stub end that comes into contact with the fluid, whereas the more economical carbon steel can be used for the loose-fitting flange. This significantly reduces the cost of the overall flanged connection.

Ease of installation and maintenance: The free rotation of the flanged stub makes alignment of the bolt holes extremely simple, greatly simplifying the installation process. It is also easier to disassemble and reassemble when equipment needs to be inspected or replaced, eliminating the need for cutting or rewelding.

Adaptable: It is easy to connect pipes made of different materials. For example, corrosion-resistant flanged short sections are used for corrosive fluids, while ordinary carbon steel pipes are used for other sections.

Stress Reduction: The flexibility of the loose flange helps to relieve stresses in the piping system due to thermal expansion or vibration, thereby extending the life of the piping system.

Applications

Equipment connections that require frequent disassembly: heat exchangers, vessels, pumps, valves

Corrosive media piping systems: in pipelines handling corrosive fluids such as acids, alkalis, brines, etc.

Oil and gas industry: oil and gas transportation, refinery equipment.

Chemical industry: various chemical production lines.

Power industry: especially in nuclear power plants and other occasions with strict material requirements.

Food and pharmaceutical industry: piping systems with high requirements for hygiene and cleanliness.

The post Lap Joint Stub End appeared first on Quality Manufacturer of Industrial Pipe Fittings.

What are Buttweld fittings?

Buttweld fittings are pipe fittings used to connect, change direction, branch, or reduce the pipe size in a permanent, welded connection. These fittings are welded to the pipe by butt welding, ensuring a strong, leak-proof joint that enhances durability and pressure resistance.

Types of Buttweld Fittings

Incoloy Buttweld Fittings: Overview

Incoloy buttweld fittings are pipe fittings made from Incoloy alloys, designed for high-temperature, high-corrosion, and high-pressure environments. These fittings are welded to pipes, ensuring a strong, leak-proof, and durable connection in critical industrial applications.

What is Incoloy?

Incoloy is a nickel-iron-chromium alloy with excellent corrosion resistance, oxidation resistance, and high-temperature strength. It is commonly used in chemical, marine, power, and aerospace industries.

Common Grades of Incoloy Buttweld Fittings

Chemical Composition of Grade Incoloy Butt weld Fittings

Mechanical Properties of Incoloy Butt weld Pipe Fittings

Incoloy Buttweld Fittings Equivalent Grades

Types of Incoloy Buttweld Fittings

Elbows (90° & 45°) – Changes pipeline direction.

Tees (Equal & Reducing) – Splits or merges fluid flow.

Reducers (Concentric & Eccentric) – Reduces pipe size.

Caps – Closes pipeline ends.

Stub Ends – Works with lap joint flanges.

Crosses – Connects four pipelines.

Step-by-Step Manufacturing Process of Incoloy Buttweld Fittings

Incoloy buttweld fittings are manufactured using precision engineering and high-quality Incoloy alloys to ensure durability, strength, and corrosion resistance. The process involves seamless or welded pipe formation, cutting, shaping, heat treatment, machining, and quality testing.

1. Raw Material Selection

Material: High-quality Incoloy alloys (800, 800H, 825, 925, etc.) in the form of seamless pipes, welded pipes, or plates.

Standard Compliance: The material must meet ASTM B366, ASTM B564, and ASME SB366 specifications.

2. Cutting & Preparation

The pipes or plates are cut to the required lengths based on the fitting design.

Plasma cutting, saw cutting, or water jet cutting is used for precision.

3. Welding (For Welded Buttweld Fittings)

If using welded pipe, TIG/MIG welding is performed.

Automatic welding processes ensure precision and uniformity.

Welded fittings undergo post-weld heat treatment (PWHT) to restore mechanical properties.

4. Heat Treatment (Annealing & Normalizing)

The fittings undergo annealing (1050-1150°C) followed by rapid cooling to:
✔ Enhance corrosion resistance
✔ Improve ductility and strength
✔ Remove internal stresses

5. Inspection & Quality Testing

All Incoloy buttweld fittings undergo strict quality checks to ensure reliability:

✅ Dimensional Inspection – Ensures compliance with ASME B16.9, B16.28, MSS-SP-43.
✅ Visual & Surface Inspection – Checks for defects, cracks, and porosity.
✅ Mechanical Testing – Hardness, tensile, and impact testing.
✅ Non-Destructive Testing (NDT) – Ultrasonic Testing (UT), Radiographic Testing (RT).
✅ Corrosion Resistance Testing – ASTM A262 (Intergranular Corrosion Test).
✅ Hydrostatic & Pneumatic Testing – Pressure and leak resistance test.

6. Marking & Packaging

Marking includes size, material grade (Incoloy 800, 825, etc.), ASTM standard, heat number, and manufacturer details.

Protective packaging ensures safe transportation and prevents surface damage.

Final Product:

✔ High-strength, corrosion-resistant Incoloy buttweld fittings suitable for oil & gas, petrochemicals, power plants, and marine applications.

What is the difference between socket weld and Butt weld fittings?

Socket weld and buttweld fittings are both used in piping systems to connect pipes, but they have distinct welding methods, applications, and pressure ratings.

Typical Applications

Socket Weld Fittings

✅ Used in high-pressure, small-diameter piping systems in:

Oil & gas pipelines

Steam & hydraulic lines

Chemical processing plants

Butt weld Fittings

✅ Used in large-diameter, high-temperature, high-pressure applications like:

Power plants (boilers, heat exchangers)

Petrochemical & refinery piping

Water treatment plants

Standards for Socket Weld & Buttweld Fittings

Welded Pipe Fittings

✅ Used in general industrial applications like:

Water distribution, HVAC, and plumbing

Structural and construction projects

Food, dairy, and pharmaceutical industries

Low-to-moderate pressure pipelines

Advantages of Incoloy Buttweld Fittings

✔ High-Temperature Strength – Performs well in extreme heat (>1100°F/593°C).
✔ Corrosion Resistance – Resists oxidation, carburization, and acid attacks.
✔ Acid & Chemical Resistance – Suitable for sulfuric, phosphoric, and nitric acids.
✔ Durability – Long lifespan in harsh industrial environments.
✔ Weldability – Easily welded using standard techniques.

Applications of Incoloy Buttweld Fittings

Petrochemical & Refinery Pipelines

Marine & Offshore Oil and Gas Industry

Heat Exchangers & Boilers

Power Plants (Nuclear, Thermal, Renewable Energy)

Aerospace & Jet Engine Components

Chemical Processing Plants

You can get an offer for products in below material forms:

-Pipe and Tube (EN 10216-5, ASTM A213, ASTM A249, A312, A790,)

-Forged Fitting and Flange (ASTM A182 , ASTM A105,ASTM B564 )

-Butt Weld Fittings (ASTM A234, ASTM A403,ASTM A815)

-Round bar , Billet (ASTM A276, ASTM A479)

– Plate, Sheet, Strip(ASTM A240, EN 10028-7, A480)

-Bolting, Nuts（ASTM A193, A194, A320）

Incoloy Buttweld Fittings Exported Countries

We Export  Incoloy Buttweld Fittings to Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Turkey, Egypt, Yemen , Syria, Jordan, Cyprus, Singapore, Malaysia, Indonesia, Thailand, Vietnam, South Korea, Japan, Sri Lanka, Maldives, Bangladesh, Cambodia, Argentina, Bolivia, Brazil, Venezuela, Colombia, Ecuador, Guyana, Paraguay, Uruguay, United States Of America, Canada, Mexico, Panama, Jamaica, Bahamas, Denmark, Norway, Germany, France,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Libya, Egypt, Sudan,  Europe, Africa, Asia, North America, South America, Middle East.etc

The post The Manufacturing Process of Incoloy Buttweld Fittings appeared first on Quality Manufacturer of Industrial Pipe Fittings.

What is ASME B16.9 Fittings?

ASME B16.9 Standard covers dimensions, tolerances, pressure ratings, testing, and markings for butt welding fittings in sizes NPS 1 ∕ 2 to NPS 48 (DN 15 to DN 1200). It covers fittings of any producible wall thickness.

What is ASME B16.5 Flanges?

ASME B16.5 standard covers Steel Pipe Flanges from NPS 1/2 to NPS 24 Inch in pressure class 150 to class 2500. It covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges.

ANSI FLANGE FITTINGS

A lot of major Chemical, Petrochemical and offshore companies choose our steel pipe flanges and fittings for corrosive and high temperature application.

We can make sure all alloy flanges and fittings in various types

• Flanges

Weld Neck, Slip-on, Blind, Socket Weld, Screwed, Lap Joint.

• Pipe Elbow Fittings

90, 60, 45, 180 Degree, Long radius and short radius;

• Pipe Reducer

Concentric and Eccentric Reducer

• Pipe Tee Fittings

Straight and Reducer Tee

• Cap

Pipe Cap and End Cap

All of them are supplied by reputable manufacturers in China. They can be provided in either seamless or welded construction and covered by specifications.

What Makes Nigeria Client buy Pipe Flanges and Elbows in so Short Time? 

We are shocked that our regular client from Nigeria placed the order in short 3 days. From the first mail of inquiry to the last mail of purchase order, there is no other needless words between us. In private communication between our sales and Robert  , he told that our immediate response, the perfect price, the safe package and friendly suggestion have made successful cooperation once by once.

How About Order Size of Alloy Flanges and Fittings

All together 100 pieces of alloy flange and elbows have been provided for our customer.

Package of Butt Weld Fittings and Flanges

We pay more attention on pipe fittings to insure that they can be received safely and intact by our customer. Packing details are as bellows:

Our staff wrapped flanges fittings with plastic foam individually, put them into cartons and wooden cases, bundled wooden cases with nylon rope.

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